0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:C000006118Member 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:C000006121Member 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:C000038033Member 2026-06-30 2026-06-30 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:C000100249Member 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:C000100250Member 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:DebtSecuritiesRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:DerivativesRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:HighYieldBondsRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:IlliquidInvestmentsRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:LeverageRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:MarketRiskAndSelectionRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:MunicipalSecuritiesRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:OperationalAndTechnologyRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member oef:RiskLoseMoneyMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:TenderOptionBondsAndRelatedSecuritiesRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:VariableRateDemandObligationsRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:DebtSecuritiesRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:DerivativesRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:HighYieldBondsRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:IlliquidInvestmentsRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:LeverageRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:MarketRiskAndSelectionRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:MunicipalSecuritiesRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:OperationalAndTechnologyRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member oef:RiskLoseMoneyMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:TenderOptionBondsAndRelatedSecuritiesRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:VariableRateDemandObligationsRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member 2026-06-30 2026-06-30 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:DebtSecuritiesRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:DerivativesRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:HighYieldBondsRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:IlliquidInvestmentsRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:LeverageRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:MarketRiskAndSelectionRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:MunicipalSecuritiesRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:OperationalAndTechnologyRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member oef:RiskLoseMoneyMember 2026-06-30 2026-06-30 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:TenderOptionBondsAndRelatedSecuritiesRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:VariableRateDemandObligationsRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:C000006122Member 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:C000006124Member 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:C000006125Member 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:C000038034Member 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:C000038035Member 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:DebtSecuritiesRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:IlliquidInvestmentsRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:LeverageRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:MarketRiskAndSelectionRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:MunicipalSecuritiesRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:OperationalAndTechnologyRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member oef:RiskLoseMoneyMember 2026-06-30 2026-06-30 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:VariableRateDemandObligationsRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:DebtSecuritiesRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:IlliquidInvestmentsRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:LeverageRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:MarketRiskAndSelectionRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:MunicipalSecuritiesRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:OperationalAndTechnologyRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member oef:RiskLoseMoneyMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:VariableRateDemandObligationsRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:DebtSecuritiesRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:IlliquidInvestmentsRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:LeverageRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:MarketRiskAndSelectionRiskMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:MunicipalSecuritiesRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:OperationalAndTechnologyRisksMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member oef:RiskLoseMoneyMember 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:VariableRateDemandObligationsRisksMember 2026-06-30 2026-06-30 0000225635 2026-06-30 2026-06-30 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006118Member 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006118Member oef:AfterTaxesOnDistributionsAndSalesMember 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006118Member oef:AfterTaxesOnDistributionsMember 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006121Member 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:C000006122Member 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:C000006122Member oef:AfterTaxesOnDistributionsAndSalesMember 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:C000006122Member oef:AfterTaxesOnDistributionsMember 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006124Member 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006125Member 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006125Member oef:AfterTaxesOnDistributionsAndSalesMember 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006125Member oef:AfterTaxesOnDistributionsMember 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000038033Member 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000038034Member 2021-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000038035Member 2021-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000038035Member oef:AfterTaxesOnDistributionsAndSalesMember 2021-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000038035Member oef:AfterTaxesOnDistributionsMember 2021-01-01 2025-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:C000100249Member 2021-01-01 2025-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:C000100249Member oef:AfterTaxesOnDistributionsAndSalesMember 2021-01-01 2025-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:C000100249Member oef:AfterTaxesOnDistributionsMember 2021-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000100250Member 2021-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000100250Member oef:AfterTaxesOnDistributionsAndSalesMember 2021-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000100250Member oef:AfterTaxesOnDistributionsMember 2021-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002334BloombergMunicipalBondIndexMember 2021-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335BloombergMunicipal15YearIndexMember 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334BloombergMunicipalBondIndexMember 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335BloombergMunicipal15YearIndexMember 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335BloombergMunicipal15YearIndexMember 2021-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335BloombergMunicipalBondIndexMember 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335BloombergMunicipalBondIndexMember 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335BloombergMunicipalBondIndexMember 2021-01-01 2025-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334BloombergMunicipalBondIndexMember 2021-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:C000006118Member 2016-01-01 2016-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:C000100249Member 2016-01-01 2016-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:C000100250Member 2016-01-01 2016-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:C000006122Member 2016-01-01 2016-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:C000006125Member 2016-01-01 2016-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:C000038035Member 2016-01-01 2016-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:C000006118Member 2017-01-01 2017-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:C000100249Member 2017-01-01 2017-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:C000100250Member 2017-01-01 2017-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:C000006122Member 2017-01-01 2017-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:C000006125Member 2017-01-01 2017-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:C000038035Member 2017-01-01 2017-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:C000006118Member 2018-01-01 2018-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:C000100249Member 2018-01-01 2018-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:C000100250Member 2018-01-01 2018-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:C000006122Member 2018-01-01 2018-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:C000006125Member 2018-01-01 2018-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:C000038035Member 2018-01-01 2018-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:C000006118Member 2019-01-01 2019-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:C000100249Member 2019-01-01 2019-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:C000100250Member 2019-01-01 2019-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:C000006122Member 2019-01-01 2019-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:C000006125Member 2019-01-01 2019-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:C000038035Member 2019-01-01 2019-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:C000006118Member 2020-01-01 2020-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:C000100249Member 2020-01-01 2020-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:C000100250Member 2020-01-01 2020-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:C000006122Member 2020-01-01 2020-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:C000006125Member 2020-01-01 2020-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:C000038035Member 2020-01-01 2020-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:C000006118Member 2021-01-01 2021-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:C000100249Member 2021-01-01 2021-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:C000100250Member 2021-01-01 2021-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:C000006122Member 2021-01-01 2021-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:C000006125Member 2021-01-01 2021-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:C000038035Member 2021-01-01 2021-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:C000006118Member 2022-01-01 2022-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:C000100249Member 2022-01-01 2022-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:C000100250Member 2022-01-01 2022-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:C000006122Member 2022-01-01 2022-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:C000006125Member 2022-01-01 2022-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:C000038035Member 2022-01-01 2022-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:C000006118Member 2023-01-01 2023-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:C000100249Member 2023-01-01 2023-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:C000100250Member 2023-01-01 2023-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:C000006122Member 2023-01-01 2023-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:C000006125Member 2023-01-01 2023-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:C000038035Member 2023-01-01 2023-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:C000006118Member 2024-01-01 2024-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:C000100249Member 2024-01-01 2024-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:C000100250Member 2024-01-01 2024-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:C000006122Member 2024-01-01 2024-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:C000006125Member 2024-01-01 2024-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:C000038035Member 2024-01-01 2024-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006118Member 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006118Member oef:AfterTaxesOnDistributionsAndSalesMember 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006118Member oef:AfterTaxesOnDistributionsMember 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006121Member 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:C000006122Member 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:C000006122Member oef:AfterTaxesOnDistributionsAndSalesMember 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:C000006122Member oef:AfterTaxesOnDistributionsMember 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006124Member 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006125Member 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006125Member oef:AfterTaxesOnDistributionsAndSalesMember 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006125Member oef:AfterTaxesOnDistributionsMember 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000038033Member 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000038034Member 2025-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000038035Member 2025-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000038035Member oef:AfterTaxesOnDistributionsAndSalesMember 2025-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000038035Member oef:AfterTaxesOnDistributionsMember 2025-01-01 2025-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:C000100249Member 2025-01-01 2025-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:C000100249Member oef:AfterTaxesOnDistributionsAndSalesMember 2025-01-01 2025-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:C000100249Member oef:AfterTaxesOnDistributionsMember 2025-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000100250Member 2025-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000100250Member oef:AfterTaxesOnDistributionsAndSalesMember 2025-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000100250Member oef:AfterTaxesOnDistributionsMember 2025-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002334BloombergMunicipalBondIndexMember 2025-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335BloombergMunicipal15YearIndexMember 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334BloombergMunicipalBondIndexMember 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334Member bmbfi:C000006118Member 2025-01-01 2025-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334Member bmbfi:C000100249Member 2025-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002334Member bmbfi:C000100250Member 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335BloombergMunicipal15YearIndexMember 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335BloombergMunicipal15YearIndexMember 2025-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335BloombergMunicipalBondIndexMember 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335BloombergMunicipalBondIndexMember 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335BloombergMunicipalBondIndexMember 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335Member bmbfi:C000006122Member 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335Member bmbfi:C000006125Member 2025-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335Member bmbfi:C000038035Member 2025-01-01 2025-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334BloombergMunicipalBondIndexMember 2025-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006118Member 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006118Member oef:AfterTaxesOnDistributionsAndSalesMember 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006118Member oef:AfterTaxesOnDistributionsMember 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006121Member 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:C000006122Member 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:C000006122Member oef:AfterTaxesOnDistributionsAndSalesMember 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:C000006122Member oef:AfterTaxesOnDistributionsMember 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006124Member 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006125Member 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006125Member oef:AfterTaxesOnDistributionsAndSalesMember 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000006125Member oef:AfterTaxesOnDistributionsMember 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000038033Member 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:C000038034Member 2016-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000038035Member 2016-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000038035Member oef:AfterTaxesOnDistributionsAndSalesMember 2016-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000038035Member oef:AfterTaxesOnDistributionsMember 2016-01-01 2025-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:C000100249Member 2016-01-01 2025-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:C000100249Member oef:AfterTaxesOnDistributionsAndSalesMember 2016-01-01 2025-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:C000100249Member oef:AfterTaxesOnDistributionsMember 2016-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000100250Member 2016-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000100250Member oef:AfterTaxesOnDistributionsAndSalesMember 2016-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:C000100250Member oef:AfterTaxesOnDistributionsMember 2016-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002334BloombergMunicipalBondIndexMember 2016-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335BloombergMunicipal15YearIndexMember 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002334BloombergMunicipalBondIndexMember 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335BloombergMunicipal15YearIndexMember 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335BloombergMunicipal15YearIndexMember 2016-01-01 2025-12-31 0000225635 bmbfi:ClassKMember bmbfi:S000002335BloombergMunicipalBondIndexMember 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorA1Member bmbfi:S000002335BloombergMunicipalBondIndexMember 2016-01-01 2025-12-31 0000225635 bmbfi:InvestorACAndInstitutionalMember bmbfi:S000002335BloombergMunicipalBondIndexMember 2016-01-01 2025-12-31 0000225635 bmbfi:ServiceSharesMember bmbfi:S000002334BloombergMunicipalBondIndexMember 2016-01-01 2025-12-31 iso4217:USD pure 0000225635 false 485BPOS 2026-06-30 0.0172 0.0289 0.0015 0.0515 0.0036 0.0711 0.0391 0.0203 -0.1035 0.0586 -0.0259 0.0448 0.0289 0.0514 -0.0006 0.0096 0.0154 0.0240 0.0127 -0.0003 0.0422 0.0234 -0.1017 0.0629 0.0192 0.0330 0.0051 0.0546 0.0066 0.0743 0.0159 0.0245 0.0131 0.0002 -0.0244 0.0453 0.0294 0.0520 -0.0006 0.0101 0.0020 0.0507 0.0046 0.0702 0.0401 0.0203 -0.1044 0.0597 0.0162 0.0299 -0.0017 0.0087 0.0134 0.0240 0.0116 -0.0013 -0.0269 0.0437 0.0279 0.0504 N-1A BLACKROCK MUNICIPAL BOND FUND, INC. 2026-10-28 Fund Overview Key Facts About BlackRock National Municipal Fund Investment Objective <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The investment objective of BlackRock National Municipal Fund (the “National Fund” or the “Fund”) is to provide </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shareholders with as high a level of income exempt from Federal income taxes as is consistent with the investment </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policies of the Fund.</span></div> Fees and Expenses of the Fund <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. Amounts in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the table are rounded to the nearest basis point, which in some cases may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">“</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">0.00.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">”</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">You may pay other fees, such </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">as brokerage commissions and other fees to your financial professional or your selected securities dealer, broker, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">investment adviser, service provider or industry professional (including BlackRock Advisors, LLC (</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">“</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">BlackRock</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">”</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">) and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">its affiliates) (each, a </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">“</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">Financial Intermediary</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">”</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">), which are not reflected in the table and example below.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> You may</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> the fund complex advised by BlackRock or its affiliates. More information about these and other discounts is available </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">from your Financial Intermediary and in the “Details About the Share Classes” and the “Intermediary-Defined Sales </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Charge Waiver Policies” sections on pages </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">35</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">A-1</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">, respectively, of the Fund’s prospectus and in the “Purchase of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Shares” section on page </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">II-97</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> of Part II of the Fund’s Statement of Additional Information..</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in the fund complex advised by BlackRock or its affiliates. 100000 Shareholder Fees (fees paid directly from your investment) 0.0425 0 0 0 0.0100 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) 0.0039 0.0039 0.0039 0.0025 0.0100 0 0.0015 0.0016 0.0017 0.0009 0.0010 0.0011 0.0006 0.0006 0.0006 0.0001 0.0001 0.0001 0.0080 0.0156 0.0057 -0.0005 -0.0006 -0.0007 0.0075 0.0150 0.0050 <div style="float: left; line-height: 7.44pt; margin-left: 9.6pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 7.44pt;">A contingent deferred sales charge (“CDSC”) of 1.00% is assessed on certain redemptions of Investor A Shares made within 18 months after </span><span style="color: #000000; font-family: arial; font-size: 7.44pt;">purchase where no initial sales charge was paid at the time of purchase as part of an investment of $250,000 or more.</span></div> June 30, 2028 The Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent Annual Financial Statements and Additional Information, which do not include Acquired Fund Fees and Expenses. Example: <div style="line-height: 10.695pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or lower, based on these assumptions your costs would be:</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> 498 665 846 1368 253 487 844 1647 51 176 311 707 You would pay the following expenses if you did not redeem your shares:  153 487 844 1647 Portfolio Turnover: <div style="line-height: 10.695pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">54</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">% of the average value of its portfolio.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> 0.54 Principal Investment Strategies of the Fund <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Under normal circumstances, the National Fund seeks to achieve its objective by investing at least 80% of its net</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> assets, plus the amount of any borrowing for investment purposes, in municipal bonds and derivatives that provide</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> investment exposure to such securities or to one or more market risk factors associated with such securities. This </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policy is a fundamental policy of the Fund and may not be changed without approval of a majority of the Fund’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">outstanding securities, as defined in the Investment Company Act. Municipal bonds include debt obligations issued by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or on behalf of a governmental entity or other qualifying issuer that pay interest that is, in the opinion of bond counsel </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to the issuer, generally excludable from gross income for Federal income tax purposes (except that the interest may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">includable in taxable income for purposes of the Federal alternative minimum tax). Municipal bonds may be obligations </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of a variety of issuers, including governmental entities or other qualifying issuers. Issuers may be states, territories </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and possessions of the United States and the District of Columbia and their political subdivisions, agencies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">instrumentalities. Municipal bonds also include short-term tax-exempt obligations like municipal notes and variable </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate demand obligations.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may invest in municipal bonds rated in any rating category or in unrated municipal bonds. Fund management </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">presently intends to invest at least 65% of the Fund’s net assets in municipal bonds rated investment grade or in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">unrated municipal bonds that Fund management believes are of comparable quality. Investment grade bonds are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">securities which are rated in the four highest categories by at least one of the major rating agencies or determined by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the management team to be of similar quality. The Fund does not intend to invest more than 35% of its net assets in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">junk bonds or in unrated bonds that Fund management believes are of comparable quality. This is a non-fundamental </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policy and may be changed by the Board at any time. The Fund will primarily invest in municipal bonds that have a </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">maturity of five years or longer.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may engage in transactions in certain derivatives, such as financial futures contracts and options thereon, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">indexed and inverse floating rate obligations and swap agreements, including credit default swap agreements. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund may use derivative instruments to hedge its investments (including anticipatory hedges) or to seek to enhance </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">returns. The Fund may leverage its assets through the use of proceeds received through tender option bond </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">transactions. In a tender option bond transaction, the Fund transfers municipal bonds or other municipal securities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">into a special purpose entity (a “TOB Trust”). A TOB Trust typically issues two classes of beneficial interests: short-term</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> floating rate interests (“TOB Floaters”), which are sold to third party investors, and residual inverse floating rate </span></div> <div style="line-height: 10.695pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">interests (“TOB Residuals”), which are generally issued to the Fund. The Fund may invest in TOB Residuals and may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">also invest in TOB Floaters. The Fund will look through to the underlying municipal bond held by a TOB Trust for </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">purposes of the Fund’s 80% policy.</span></div> Under normal circumstances, the National Fund seeks to achieve its objective by investing at least 80% of its net assets, plus the amount of any borrowing for investment purposes, in municipal bonds and derivatives that provide investment exposure to such securities or to one or more market risk factors associated with such securities. <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may invest in municipal bonds rated in any rating category or in unrated municipal bonds. Fund management </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">presently intends to invest at least 65% of the Fund’s net assets in municipal bonds rated investment grade or in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">unrated municipal bonds that Fund management believes are of comparable quality. Investment grade bonds are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">securities which are rated in the four highest categories by at least one of the major rating agencies or determined by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the management team to be of similar quality. The Fund does not intend to invest more than 35% of its net assets in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">junk bonds or in unrated bonds that Fund management believes are of comparable quality. This is a non-fundamental </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policy and may be changed by the Board at any time. The Fund will primarily invest in municipal bonds that have a </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">maturity of five years or longer.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may engage in transactions in certain derivatives, such as financial futures contracts and options thereon, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">indexed and inverse floating rate obligations and swap agreements, including credit default swap agreements. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund may use derivative instruments to hedge its investments (including anticipatory hedges) or to seek to enhance </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">returns. The Fund may leverage its assets through the use of proceeds received through tender option bond </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">transactions. In a tender option bond transaction, the Fund transfers municipal bonds or other municipal securities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">into a special purpose entity (a “TOB Trust”). A TOB Trust typically issues two classes of beneficial interests: short-term</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> floating rate interests (“TOB Floaters”), which are sold to third party investors, and residual inverse floating rate </span></div> <div style="line-height: 10.695pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">interests (“TOB Residuals”), which are generally issued to the Fund. The Fund may invest in TOB Residuals and may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">also invest in TOB Floaters. The Fund will look through to the underlying municipal bond held by a TOB Trust for </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">purposes of the Fund’s 80% policy.</span></div> You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Debt Securities Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Debt securities, such as bonds, involve risks, such as credit risk, interest rate risk, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">extension risk, and prepayment risk, each of which are described in further detail below:</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Credit Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Credit risk refers to the possibility that the issuer of a debt security (i.e., the borrower) will not be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">able to make payments of interest and principal when due. Changes in an issuer’s credit rating or the market’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Interest Rate Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The market value of bonds and other fixed-income securities changes in response to interest </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate changes and other factors. Interest rate risk is the risk that prices of bonds and other fixed-income securities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">will increase as interest rates fall and decrease as interest rates rise.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may be subject to a greater risk of rising interest rates during a period of low interest rates. For example, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">if interest rates increase by 1%, assuming a current portfolio duration of ten years, and all other factors being </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">equal, the value of the Fund’s investments would be expected to decrease by 10%. (Duration is a measure of the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">price sensitivity of a debt security or portfolio of debt securities to relative changes in interest rates.) The magnitude </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of these fluctuations in the market price of bonds and other fixed-income securities is generally greater for those </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">securities with longer maturities. Fluctuations in the market price of the Fund’s investments will not affect interest </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">income derived from instruments already owned by the Fund, but will be reflected in the Fund’s net asset value. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund may lose money if short-term or long-term interest rates rise sharply in a manner not anticipated by Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">management.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">To the extent the Fund invests in debt securities that may be prepaid at the option of the obligor (such as mortgage-backed</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> securities), the sensitivity of such securities to changes in interest rates may increase (to the detriment of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund) when interest rates rise. Moreover, because rates on certain floating rate debt securities typically reset </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">only periodically, changes in prevailing interest rates (and particularly sudden and significant changes) can be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">expected to cause some fluctuations in the net asset value of the Fund to the extent that it invests in floating rate </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">debt securities.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">These basic principles of bond prices also apply to U.S. Government securities. A security backed by the “full faith </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and credit” of the U.S. Government is guaranteed only as to its stated interest rate and face value at maturity, not </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">its current market price. Just like other fixed-income securities, government-guaranteed securities will fluctuate in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">value when interest rates change.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">A general rise in interest rates has the potential to cause investors to move out of fixed-income securities on a large </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">scale, which may increase redemptions from funds that hold large amounts of fixed-income securities. Heavy </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">redemptions could cause the Fund to sell assets at inopportune times or at a loss or depressed value and could </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">hurt the Fund’s performance.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Extension Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — When interest rates rise, certain obligations will be paid off by the obligor more slowly than </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">anticipated, causing the value of these obligations to fall.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Prepayment Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — When interest rates fall, certain obligations will be paid off by the obligor more quickly than </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">originally anticipated, and the Fund may have to invest the proceeds in securities with lower yields.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Municipal Securities Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Municipal securities risks include the ability of the issuer to repay the obligation, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">relative lack of information about certain issuers of municipal securities, and the possibility of future legislative </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">changes which could affect the market for and value of municipal securities. Budgetary constraints of local, state, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and federal governments upon which the issuers may be relying for funding may also impact municipal securities. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">These risks include:</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">General Obligation Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Timely payments depend on the issuer’s credit quality, ability to raise tax </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">revenues and ability to maintain an adequate tax base.</span></div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Revenue Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> These payments depend on the money earned by the particular facility or class of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">facilities, or the amount of revenues derived from another source.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Private Activity Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Municipalities and other public authorities issue private activity bonds to finance </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">development of industrial facilities for use by a private enterprise. The private enterprise pays the principal and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">interest on the bond, and the issuer does not pledge its full faith, credit and taxing power for repayment.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Moral Obligation Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Moral obligation bonds are generally issued by special purpose public authorities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of a state or municipality. If the issuer is unable to meet its obligations, repayment of these bonds becomes a moral </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">commitment, but not a legal obligation, of the state or municipality.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Municipal Notes Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Municipal notes are shorter term municipal debt obligations. If there is a shortfall in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">anticipated proceeds, the notes may not be fully repaid and the Fund may lose money.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Municipal Lease Obligations Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> In a municipal lease obligation, the issuer agrees to make payments when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">due on the lease obligation. Although the issuer does not pledge its unlimited taxing power for payment of the lease </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">obligation, the lease obligation is secured by the leased property.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Tax-Exempt Status Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The Fund and its investment manager will rely on the opinion of issuers’ bond counsel </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and, in the case of derivative securities, sponsors’ counsel, on the tax-exempt status of interest on municipal bonds </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and payments under derivative securities. Neither the Fund nor its investment manager will independently review the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">bases for those tax opinions, which may ultimately be determined to be incorrect and subject the Fund and its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shareholders to substantial tax liabilities.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">High Yield Bonds Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Although junk bonds generally pay higher rates of interest than investment grade bonds, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">junk bonds are high risk investments that are considered speculative and may cause income and principal losses </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the Fund.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.0pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Derivatives Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund’s use of derivatives may increase its costs, reduce the Fund’s returns and/or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">increase volatility. Derivatives involve significant risks, including:</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Leverage Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund’s use of derivatives can magnify the Fund’s gains and losses. Relatively small market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">movements may result in large changes in the value of a derivatives position and can result in losses that greatly </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">exceed the amount originally invested.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Market Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Some derivatives are more sensitive to interest rate changes and market price fluctuations than </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">other securities. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">market movements, which losses are potentially unlimited. Finally, BlackRock may not be able to predict correctly </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the direction of securities prices, interest rates and other economic factors, which could cause the Fund’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">derivatives positions to lose value.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Counterparty Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Derivatives are also subject to counterparty risk, which is the risk that the other party in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">transaction will be unable or unwilling to fulfill its contractual obligation, and the related risks of having concentrated </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">exposure to such a counterparty.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Illiquidity Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">difficult for the Fund to value accurately.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Operational Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The use of derivatives includes the risk of potential operational issues, including documentation </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">issues, settlement issues, systems failures, inadequate controls and human error.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Legal Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The risk of insufficient documentation, insufficient capacity or authority of counterparty, or legality or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">enforceability of a contract.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Volatility and Correlation Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Volatility is defined as the characteristic of a security, an index or a market to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">fluctuate significantly in price within a short time period. A risk of the Fund’s use of derivatives is that the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">fluctuations in their values may not correlate with the overall securities markets.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Valuation Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Valuation for derivatives may not be readily available in the market. Valuation may be more difficult </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">in times of market turmoil since many investors and market makers may be reluctant to purchase complex </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">instruments or quote prices for them.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Hedging Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Hedges are sometimes subject to imperfect matching between the derivative and the underlying </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">security, and there can be no assurance that the Fund’s hedging transactions will be effective. The use of hedging </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may result in certain adverse tax consequences.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Tax Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Certain aspects of the tax treatment of derivative instruments, including swap agreements and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">commodity-linked derivative instruments, are currently unclear and may be affected by changes in legislation, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">regulations or other legally binding authority. Such treatment may be less favorable than that given to a direct </span></div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment in an underlying asset and may adversely affect the timing, character and amount of income the Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">realizes from its investments.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Regulatory Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Derivative contracts are subject to regulation under the Dodd-Frank Wall Street Reform and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Consumer Protection Act (the “Dodd-Frank Act”) in the United States and under comparable regimes in Europe, Asia </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and other non-U.S. jurisdictions. Under the Dodd-Frank Act, with respect to uncleared swaps, swap dealers are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">required to exchange variation margin with the Fund and may be required by applicable regulations to collect and/or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">exchange initial margin with the Fund. Both initial and variation margin may be comprised of cash and/or securities, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">subject to applicable regulatory haircuts. In certain cases, shares of investment companies may not be posted as </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">collateral under applicable regulations. In addition, regulations adopted by global prudential regulators require </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">certain bank-regulated counterparties and certain of their affiliates to include in certain financial contracts, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">including many derivatives contracts, terms that delay or restrict the rights of counterparties, such as the Fund, to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">terminate such contracts, foreclose upon collateral, exercise other default rights or restrict transfers of credit </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">support in the event that the counterparty and/or its affiliates are subject to certain types of resolution or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">insolvency proceedings. The implementation of these requirements with respect to derivatives, as well as </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">regulations under global regulations regarding clearing, mandatory trading and margining of other derivatives, may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">increase the costs and risks to the Fund of trading in these instruments and, as a result, may affect returns to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investors in the Fund. Future regulatory developments may impact the Fund’s ability to invest or remain invested in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">certain derivatives. Legislation or regulation may also change the way in which the Fund itself is regulated. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">BlackRock cannot predict the effects of any new governmental regulation that may be implemented on the ability of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund to use swaps or any other financial derivative product, and there can be no assurance that any new </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">governmental regulation will not adversely affect the Fund’s ability to achieve its investment objective.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Illiquid Investments Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund may not acquire any illiquid investment if, immediately after the acquisition, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund would have invested more than 15% of its net assets in illiquid investments. An illiquid investment is any </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">calendar days or less without the sale or disposition significantly changing the market value of the investment. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Liquid investments may become illiquid after purchase by the Fund, particularly during periods of market turmoil. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">There can be no assurance that a security or instrument that is deemed to be liquid when purchased will continue </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to be liquid for as long as it is held by the Fund, and any security or instrument held by the Fund may be deemed an </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">illiquid investment pursuant to the Fund’s liquidity risk management program. The Fund’s illiquid investments may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">reduce the returns of the Fund because it may be difficult to sell the illiquid investments at an advantageous time </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or price. In addition, if the Fund is limited in its ability to dispose of illiquid investments during periods when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shareholders are redeeming or selling their shares or the Fund’s net assets otherwise shrink, the Fund will need to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">dispose of liquid securities to meet redemption requests and illiquid securities will become a larger portion of the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund’s holdings. An investment may be illiquid due to, among other things, the reduced number and capacity of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">traditional market participants to make a market in fixed-income securities or the lack of an active trading market. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">To the extent that the Fund’s principal investment strategies involve derivatives or securities with substantial market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and/or credit risk, the Fund will tend to have greater exposure to the risks associated with illiquid investments. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Illiquid investments may be harder to value, especially in changing markets, and if the Fund is forced to sell these </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investments to meet redemption requests or for other cash needs, the Fund may suffer a loss. This may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">magnified in a rising interest rate environment or other circumstances where investor redemptions or sales of Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shares may be higher than normal. In addition, when there is illiquidity in the market for certain securities, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund, due to limitations on illiquid investments, may be subject to purchase and sale restrictions.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Leverage Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Some transactions may give rise to a form of economic leverage. These transactions may include, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">among others, derivatives, and may expose the Fund to greater risk and increase its costs. The use of leverage may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to meet the applicable requirements of the Investment Company Act of 1940, as amended (the “Investment </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Company Act”), and the rules thereunder. Increases and decreases in the value of the Fund’s portfolio will be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">magnified when the Fund uses leverage.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.0pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Market Risk and Selection Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Market risk is the risk that one or more markets in which the Fund invests will </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">go down in value, including the possibility that the markets will go down sharply and unpredictably. An investor could </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">lose money over short periods due to fluctuation in the Fund’s net asset value in response to short-term market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">movements and over longer periods during market downturns. Securities or other investments held by the Fund may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">underperform the markets, the relevant indices or benchmarks, or the securities selected by other funds with </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">similar investment objectives and investment strategies, or may otherwise fail to perform as intended. The value of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">a security or other asset may decline due to changes in general market conditions, economic trends or events that </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">are not specifically related to the issuer of the security or other asset, or factors that affect a particular issuer or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">issuers, exchange, country, group of countries, region, market, industry, group of industries, sector or asset class. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The success of the Fund’s activities could be affected by interest rates, availability of credit, inflation rates, </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">economic uncertainty, changes in laws, tariffs and trade barriers, supply chain disruptions, economic sanctions, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">currency exchange controls, and local, regional or global events such as war, acts of terrorism, natural and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">environmental disasters, the spread of infectious illness or other public health issues, recessions, or other events.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Recent policy initiatives undertaken by the U.S. government have the potential to impact international relations, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">trade agreements and the overall regulatory environment in ways that could create uncertainty and instability in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">domestic and global markets, and could adversely affect the investment performance of the Fund. In particular, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">actions taken by the U.S. government in respect of international trade relations could lead to trade wars, increased </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">costs for imported goods, disruptions in supply chains, reduced foreign investment, and instability in regions where </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund invests.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Operational and Technology Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund is directly and indirectly susceptible to operational and technology </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">risks, including those related to human errors, processing errors, communication errors, systems failures, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">cybersecurity incidents, and the use of artificial intelligence and machine learning (“AI”), which may result in losses </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the Fund and its shareholders or may impair the Fund’s operations. While the Fund’s service providers are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">required to have appropriate operational, information security and cybersecurity risk management policies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">procedures, their methods of risk management may differ from those of the Fund. Operational and technology risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the issuers in which the Fund invests could also result in material adverse consequences for such issuers and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may cause the Fund’s investments in such issuers to lose value.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Tender Option Bonds and Related Securities Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The Fund’s participation in tender option bond transactions </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may reduce the Fund’s returns and/or increase volatility. Investments in tender option bond transactions expose the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund to counterparty risk and leverage risk. An investment in a tender option bond transaction typically will involve </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">greater risk than an investment in a municipal fixed rate security, including the risk of loss of principal. Distributions </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">on TOB Residuals will bear an inverse relationship to short-term municipal security interest rates. Distributions on </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">TOB Residuals paid to the Fund will be reduced or, in the extreme, eliminated as short-term municipal interest rates </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rise and will increase when short-term municipal interest rates fall. TOB Residuals generally will underperform the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">market for fixed rate municipal securities in a rising interest rate environment. The Fund may invest in TOB Trusts on </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">either a non-recourse or recourse basis. If the Fund invests in a TOB Trust on a recourse basis, it could suffer </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">losses in excess of the value of its TOB Residuals.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Variable Rate Demand Obligations Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Variable rate demand obligations are floating rate securities that </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">combine an interest in a long-term municipal bond with a right to demand payment before maturity from a bank or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">other financial institution. If the bank or financial institution is unable to pay, the Fund may lose money.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> Performance Information <div style="margin-top: 3pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The information shows you how the Fund’s performance has varied year by year and provides some indication of the</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> risks of investing in the Fund. The table compares the Fund’s performance to that of the Bloomberg Municipal Bond </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Index. To the extent that dividends and distributions have been paid by the Fund, the performance information for the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund in the chart and table assumes reinvestment of the dividends and distributions. As with all such investments,</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> past performance (before and after taxes) is not an indication of future results. Sales charges are not reflected in the</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> sales charges. If the Fund’s investment manager and its affiliates had not waived or reimbursed certain Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">expenses during these periods, the Fund’s returns would have been lower. Updated information on the Fund’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">performance, including its current net asset value, can be obtained by visiting </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">www.blackrock.com</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> or can be obtained </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">by phone at </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">(800) 882-0052</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">.</span></div> The information shows you how the Fund’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance (before and after taxes) is not an indication of future results. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. www.blackrock.com (800) 882-0052 Investor A Shares ANNUAL TOTAL RETURNS BlackRock National Municipal Fund As of 12/31 <div style="margin-top: 3pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">During the ten-year period shown in the bar chart, the highest return for a quarter was 5.76% (quarter ended </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">December 31, 2023) and the lowest return for a quarter was -6.19% (quarter ended March 31, 2022). The year-to-date return as of September 30, 2026 was -3.23%.</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> highest return 0.0576 2023-12-31 lowest return -0.0619 2022-03-31 year-to-date return 2026-09-30 -0.0323 For the periods ended 12/31/25Average Annual Total Returns -0.0149 -0.0062 0.0133 -0.0149 -0.0065 0.0131 0.0051 0.0013 0.0161 0.0123 -0.0048 0.0117 0.0324 0.0052 0.0203 0.0425 0.0080 0.0234 <div style="margin-top: 12pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Investor A Shares only, and the after-tax returns for Investor C and Institutional Shares will vary.</span></div> After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Investor A Shares only, and the after-tax returns for Investor C and Institutional Shares will vary. Fund Overview Key Facts About BlackRock Short Duration Muni Fund Investment Objective <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The investment objective of BlackRock Short Duration Muni Fund (formerly, BlackRock Short-Term Municipal Fund) (the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">“Short Duration Fund” or the “Fund”) is to provide shareholders with as high a level of income exempt from Federal </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">income taxes as is consistent with the investment policies of the Fund.</span></div> Fees and Expenses of the Fund <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. Amounts in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the table are rounded to the nearest basis point, which in some cases may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">“</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">0.00.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">”</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">You may pay other fees, such </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">as brokerage commissions and other fees to your financial professional or your selected securities dealer, broker, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">investment adviser, service provider or industry professional (including BlackRock Advisors, LLC (</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">“</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">BlackRock</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">”</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">) and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">its affiliates) (each, a </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">“</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">Financial Intermediary</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">”</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">), which are not reflected in the table and example below.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> You may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">fund complex advised by BlackRock or its affiliates. More information about these and other discounts is available </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">from your Financial Intermediary and in the “Details About the Share Classes” and the “Intermediary-Defined Sales </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Charge Waiver Policies” sections on pages </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">35</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">A-1</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">, respectively, of the Fund’s prospectus and in the “Purchase of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Shares” section on page </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">II-97</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> of Part II of the Fund’s Statement of Additional Information.</span></div> You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in the fund complex advised by BlackRock or its affiliates. 50000 Shareholder Fees (fees paid directly from your investment) 0.0300 0 0 0 0.0100 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) 0.0029 0.0029 0.0029 0.0025 0.0100 0 0.0011 0.0016 0.0018 0.0001 0.0001 0.0001 0.0066 0.0146 0.0048 -0.0005 -0.0009 -0.0011 0.0061 0.0137 0.0037 A contingent deferred sales charge (“CDSC”) of 0.25% is assessed on certain redemptions of Investor A Shares made within 9 months after purchase where no initial sales charge was paid at the time of purchase as part of an investment of $250,000 or more. June 30, 2028 Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent Annual Financial Statements and Additional Information, which does not include Acquired Fund Fees and Expenses. Example: <div style="line-height: 10.695pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or lower, based on these assumptions your costs would be:</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> 360 500 652 1093 239 453 789 1521 38 143 258 593 You would pay the following expenses if you did not redeem your shares:  139 453 789 1521 Portfolio Turnover: <div style="line-height: 10.695pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">44</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">% of the average value of its portfolio.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> 0.44 Principal Investment Strategies of the Fund <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Under normal circumstances, the Short Duration Fund seeks to achieve its objective by investing at least 80% of its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">net assets, plus the amount of any borrowing for investment purposes, in municipal bonds and derivatives that provide </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment exposure to such securities or to one or more market risk factors associated with such securities. This </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policy is a fundamental policy of the Fund and may not be changed without approval of a majority of the Fund’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">outstanding securities, as defined in the Investment Company Act. Municipal bonds include debt obligations issued by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or on behalf of a governmental entity or other qualifying issuer that pay interest that is, in the opinion of bond counsel </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to the issuer, generally excludable from gross income for Federal income tax purposes (except that the interest may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">includable in taxable income for purposes of the Federal alternative minimum tax). Municipal bonds may be obligations </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of a variety of issuers, including governmental entities or other qualifying issuers. Issuers may be states, territories </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and possessions of the United States and the District of Columbia and their political subdivisions, agencies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">instrumentalities. Municipal bonds also include short-term tax-exempt obligations like municipal notes and variable </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate demand obligations.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Under normal circumstances, the Short Duration Fund seeks to achieve its objective by investing at least 80% of its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">net assets, plus the amount of any borrowing for investment purposes, in municipal bonds and derivatives that provide </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment exposure to such securities or to one or more market risk factors associated with such securities. This </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policy is a fundamental policy of the Fund and may not be changed without approval of a majority of the Fund’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">outstanding securities, as defined in the Investment Company Act. Municipal bonds include debt obligations issued by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or on behalf of a governmental entity or other qualifying issuer that pay interest that is, in the opinion of bond counsel </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to the issuer, generally excludable from gross income for Federal income tax purposes (except that the interest may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">includable in taxable income for purposes of the Federal alternative minimum tax). Municipal bonds may be obligations </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of a variety of issuers, including governmental entities or other qualifying issuers. Issuers may be states, territories </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and possessions of the United States and the District of Columbia and their political subdivisions, agencies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">instrumentalities. Municipal bonds also include short-term tax-exempt obligations like municipal notes and variable </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate demand obligations.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Short Duration Fund invests primarily in investment grade municipal bonds or municipal notes, including variable </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate demand obligations. Investment grade bonds are securities which are rated in the four highest categories by at </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">least one of the major rating agencies or determined by the management team to be of similar quality. Generally, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">higher the rating of a bond, the higher the likelihood that interest and principal payments will be made on time. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Municipal notes are shorter-term municipal debt obligations that pay interest that is, in the opinion of bond counsel to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the issuer, generally excludable from gross income for Federal income tax purposes (except that the interest may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">includable in taxable income for purposes of the Federal alternative minimum tax) and that have a maturity that is </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">generally one year or less.</span></div> <div style="margin-top: 7pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Under normal circumstances, the effective duration of the Fund’s portfolio is expected to be 4 years or less, as </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">calculated by the Fund’s management team. Effective duration is a measure of the Fund’s price sensitivity to changes </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">in yields or interest rates; however, investors should be aware that effective duration is not an exact measurement and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may not reliably predict a particular security’s price sensitivity to changes in yield or interest rates.</span></div> Under normal circumstances, the Short Duration Fund seeks to achieve its objective by investing at least 80% of its net assets, plus the amount of any borrowing for investment purposes, in municipal bonds and derivatives that provide investment exposure to such securities or to one or more market risk factors associated with such securities. <div style="margin-top: 7pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Under normal circumstances, the effective duration of the Fund’s portfolio is expected to be 4 years or less, as </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">calculated by the Fund’s management team. Effective duration is a measure of the Fund’s price sensitivity to changes </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">in yields or interest rates; however, investors should be aware that effective duration is not an exact measurement and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may not reliably predict a particular security’s price sensitivity to changes in yield or interest rates.</span></div> You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Debt Securities Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Debt securities, such as bonds, involve risks, such as credit risk, interest rate risk, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">extension risk, and prepayment risk, each of which are described in further detail below:</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Credit Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Credit risk refers to the possibility that the issuer of a debt security (i.e., the borrower) will not be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">able to make payments of interest and principal when due. Changes in an issuer’s credit rating or the market’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Interest Rate Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The market value of bonds and other fixed-income securities changes in response to interest </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate changes and other factors. Interest rate risk is the risk that prices of bonds and other fixed-income securities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">will increase as interest rates fall and decrease as interest rates rise.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may be subject to a greater risk of rising interest rates during a period of low interest rates. For example, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">if interest rates increase by 1%, assuming a current portfolio duration of ten years, and all other factors being </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">equal, the value of the Fund’s investments would be expected to decrease by 10%. (Duration is a measure of the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">price sensitivity of a debt security or portfolio of debt securities to relative changes in interest rates.) The magnitude </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of these fluctuations in the market price of bonds and other fixed-income securities is generally greater for those </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">securities with longer maturities. Fluctuations in the market price of the Fund’s investments will not affect interest </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">income derived from instruments already owned by the Fund, but will be reflected in the Fund’s net asset value. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund may lose money if short-term or long-term interest rates rise sharply in a manner not anticipated by Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">management.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">To the extent the Fund invests in debt securities that may be prepaid at the option of the obligor (such as mortgage-backed</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> securities), the sensitivity of such securities to changes in interest rates may increase (to the detriment of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund) when interest rates rise. Moreover, because rates on certain floating rate debt securities typically reset </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">only periodically, changes in prevailing interest rates (and particularly sudden and significant changes) can be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">expected to cause some fluctuations in the net asset value of the Fund to the extent that it invests in floating rate </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">debt securities.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">These basic principles of bond prices also apply to U.S. Government securities. A security backed by the “full faith </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and credit” of the U.S. Government is guaranteed only as to its stated interest rate and face value at maturity, not </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">its current market price. Just like other fixed-income securities, government-guaranteed securities will fluctuate in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">value when interest rates change.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">A general rise in interest rates has the potential to cause investors to move out of fixed-income securities on a large </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">scale, which may increase redemptions from funds that hold large amounts of fixed-income securities. Heavy </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">redemptions could cause the Fund to sell assets at inopportune times or at a loss or depressed value and could </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">hurt the Fund’s performance.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Extension Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — When interest rates rise, certain obligations will be paid off by the obligor more slowly than </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">anticipated, causing the value of these obligations to fall.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Prepayment Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — When interest rates fall, certain obligations will be paid off by the obligor more quickly than </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">originally anticipated, and the Fund may have to invest the proceeds in securities with lower yields.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Municipal Securities Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Municipal securities risks include the ability of the issuer to repay the obligation, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">relative lack of information about certain issuers of municipal securities, and the possibility of future legislative </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">changes which could affect the market for and value of municipal securities. Budgetary constraints of local, state, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and federal governments upon which the issuers may be relying for funding may also impact municipal securities. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">These risks include:</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">General Obligation Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Timely payments depend on the issuer’s credit quality, ability to raise tax </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">revenues and ability to maintain an adequate tax base.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Revenue Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> These payments depend on the money earned by the particular facility or class of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">facilities, or the amount of revenues derived from another source.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Private Activity Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Municipalities and other public authorities issue private activity bonds to finance </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">development of industrial facilities for use by a private enterprise. The private enterprise pays the principal and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">interest on the bond, and the issuer does not pledge its full faith, credit and taxing power for repayment.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Moral Obligation Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Moral obligation bonds are generally issued by special purpose public authorities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of a state or municipality. If the issuer is unable to meet its obligations, repayment of these bonds becomes a moral </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">commitment, but not a legal obligation, of the state or municipality.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Municipal Notes Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Municipal notes are shorter term municipal debt obligations. If there is a shortfall in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">anticipated proceeds, the notes may not be fully repaid and the Fund may lose money.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Municipal Lease Obligations Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> In a municipal lease obligation, the issuer agrees to make payments when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">due on the lease obligation. Although the issuer does not pledge its unlimited taxing power for payment of the lease </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">obligation, the lease obligation is secured by the leased property.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Tax-Exempt Status Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The Fund and its investment manager will rely on the opinion of issuers’ bond counsel </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and, in the case of derivative securities, sponsors’ counsel, on the tax-exempt status of interest on municipal bonds </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and payments under derivative securities. Neither the Fund nor its investment manager will independently review the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">bases for those tax opinions, which may ultimately be determined to be incorrect and subject the Fund and its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shareholders to substantial tax liabilities.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.0pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Market Risk and Selection Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Market risk is the risk that one or more markets in which the Fund invests will </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">go down in value, including the possibility that the markets will go down sharply and unpredictably. An investor could </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">lose money over short periods due to fluctuation in the Fund’s net asset value in response to short-term market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">movements and over longer periods during market downturns. Securities or other investments held by the Fund may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">underperform the markets, the relevant indices or benchmarks, or the securities selected by other funds with </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">similar investment objectives and investment strategies, or may otherwise fail to perform as intended. The value of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">a security or other asset may decline due to changes in general market conditions, economic trends or events that </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">are not specifically related to the issuer of the security or other asset, or factors that affect a particular issuer or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">issuers, exchange, country, group of countries, region, market, industry, group of industries, sector or asset class. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The success of the Fund’s activities could be affected by interest rates, availability of credit, inflation rates, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">economic uncertainty, changes in laws, tariffs and trade barriers, supply chain disruptions, economic sanctions, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">currency exchange controls, and local, regional or global events such as war, acts of terrorism, natural and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">environmental disasters, the spread of infectious illness or other public health issues, recessions, or other events.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Recent policy initiatives undertaken by the U.S. government have the potential to impact international relations, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">trade agreements and the overall regulatory environment in ways that could create uncertainty and instability in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">domestic and global markets, and could adversely affect the investment performance of the Fund. In particular, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">actions taken by the U.S. government in respect of international trade relations could lead to trade wars, increased </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">costs for imported goods, disruptions in supply chains, reduced foreign investment, and instability in regions where </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund invests.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Illiquid Investments Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund may not acquire any illiquid investment if, immediately after the acquisition, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund would have invested more than 15% of its net assets in illiquid investments. An illiquid investment is any </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">calendar days or less without the sale or disposition significantly changing the market value of the investment. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Liquid investments may become illiquid after purchase by the Fund, particularly during periods of market turmoil. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">There can be no assurance that a security or instrument that is deemed to be liquid when purchased will continue </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to be liquid for as long as it is held by the Fund, and any security or instrument held by the Fund may be deemed an </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">illiquid investment pursuant to the Fund’s liquidity risk management program. The Fund’s illiquid investments may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">reduce the returns of the Fund because it may be difficult to sell the illiquid investments at an advantageous time </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or price. In addition, if the Fund is limited in its ability to dispose of illiquid investments during periods when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shareholders are redeeming or selling their shares or the Fund’s net assets otherwise shrink, the Fund will need to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">dispose of liquid securities to meet redemption requests and illiquid securities will become a larger portion of the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund’s holdings. An investment may be illiquid due to, among other things, the reduced number and capacity of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">traditional market participants to make a market in fixed-income securities or the lack of an active trading market. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">To the extent that the Fund’s principal investment strategies involve derivatives or securities with substantial market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and/or credit risk, the Fund will tend to have greater exposure to the risks associated with illiquid investments. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Illiquid investments may be harder to value, especially in changing markets, and if the Fund is forced to sell these </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investments to meet redemption requests or for other cash needs, the Fund may suffer a loss. This may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">magnified in a rising interest rate environment or other circumstances where investor redemptions or sales of Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shares may be higher than normal. In addition, when there is illiquidity in the market for certain securities, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund, due to limitations on illiquid investments, may be subject to purchase and sale restrictions.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Leverage Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Some transactions may give rise to a form of economic leverage. These transactions may include, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">among others, derivatives, and may expose the Fund to greater risk and increase its costs. The use of leverage may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to meet the applicable requirements of the Investment Company Act of 1940, as amended (the “Investment </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Company Act”), and the rules thereunder. Increases and decreases in the value of the Fund’s portfolio will be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">magnified when the Fund uses leverage.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Operational and Technology Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund is directly and indirectly susceptible to operational and technology </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">risks, including those related to human errors, processing errors, communication errors, systems failures, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">cybersecurity incidents, and the use of artificial intelligence and machine learning (“AI”), which may result in losses </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the Fund and its shareholders or may impair the Fund’s operations. While the Fund’s service providers are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">required to have appropriate operational, information security and cybersecurity risk management policies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">procedures, their methods of risk management may differ from those of the Fund. Operational and technology risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the issuers in which the Fund invests could also result in material adverse consequences for such issuers and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may cause the Fund’s investments in such issuers to lose value.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Variable Rate Demand Obligations Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">—</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Variable rate demand obligations are floating rate securities that </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">combine an interest in a long term municipal bond with a right to demand payment before maturity from a bank or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">other financial institution. If the bank or financial institution is unable to pay, the Fund may lose money.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> Performance Information <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The information shows you how the Fund’s performance has varied year by year and provides some indication of the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">risks of investing in the Fund. The table compares the Fund’s performance to that of the Bloomberg Municipal Bond </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Index and the Bloomberg Municipal 1-5 Year Index. To the extent that dividends and distributions have been paid by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund, the performance information for the Fund in the chart and table assumes reinvestment of the dividends and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">distributions. As with all such investments, past performance (before and after taxes) is not an indication of future </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">results. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">However, the table includes all applicable fees and sales charges. If the Fund’s investment manager and its affiliates </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">had not waived or reimbursed certain Fund expenses during these periods, the Fund’s returns would have been lower. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Updated information on the Fund’s performance, including its current net asset value, can be obtained by visiting </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">www.blackrock.com</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> or can be obtained by phone at </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">(800) 882-0052</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">.</span></div> The information shows you how the Fund’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance (before and after taxes) is not an indication of future results. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. www.blackrock.com (800) 882-0052 Institutional Shares ANNUAL TOTAL RETURNS BlackRock Short Duration Muni Fund As of 12/31 <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">During the ten-year period shown in the bar chart, the highest return for a quarter was 3.24% (quarter ended </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">December 31, 2023) and the lowest return for a quarter was -2.62% (quarter ended March 31, 2022). The year-to-date return</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> as of September 30, 2026 was -1.29%.</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> highest return 0.0324 2023-12-31 lowest return -0.0262 2022-03-31 year-to-date return 2026-09-30 -0.0129 For the periods ended 12/31/25Average Annual Total Returns 0.0514 0.0194 0.0159 0.0514 0.0194 0.0159 0.0451 0.0201 0.0161 0.0174 0.0108 0.0102 0.0315 0.0092 0.0071 0.0425 0.0080 0.0234 0.0411 0.0136 0.0167 <div style="margin-top: 12pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Institutional Shares only, and the after-tax returns for Investor A and Investor C Shares will vary.</span></div> After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Institutional Shares only, and the after-tax returns for Investor A and Investor C Shares will vary. Fund Overview Key Facts About BlackRock National Municipal Fund Investment Objective <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The investment objective of BlackRock National Municipal Fund (the “National Fund” or the “Fund”) is to provide </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shareholders with as high a level of income exempt from Federal income taxes as is consistent with the investment </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policies of the Fund.</span></div> Fees and Expenses of the Fund <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">This table describes the fees and expenses that you may pay if you buy, hold and sell Class K Shares of the Fund. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Amounts in the table are rounded to the nearest basis point, which in some cases may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">“</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">0.00.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">”</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">You may pay other </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">fees, such as brokerage commissions and other fees to your financial professional or your selected securities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">dealer, broker, investment adviser, service provider or industry professional (including BlackRock Advisors, LLC </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">(“BlackRock”) and its affiliates) (each a “Financial Intermediary”), which are not reflected in the table and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">example below.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) 0.0039 0 0.0008 0.0002 0.0006 0.0001 0.0048 -0.0003 0.0045 June 30, 2028 The Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent Annual Financial Statements and Additional Information, which do not include Acquired Fund Fees and Expenses. Example: <div style="line-height: 10.695pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or lower, based on these assumptions your costs would be:</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> 46 151 266 601 Portfolio Turnover: <div style="line-height: 10.695pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">54</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">% of the average value of its portfolio.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> 0.54 Principal Investment Strategies of the Fund <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Under normal circumstances, the National Fund seeks to achieve its objective by investing at least 80% of its net</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> assets, plus the amount of any borrowing for investment purposes, in municipal bonds and derivatives that provide</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> investment exposure to such securities or to one or more market risk factors associated with such securities. This </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policy is a fundamental policy of the Fund and may not be changed without approval of a majority of the Fund’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">outstanding securities, as defined in the Investment Company Act. Municipal bonds include debt obligations issued by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or on behalf of a governmental entity or other qualifying issuer that pay interest that is, in the opinion of bond counsel </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to the issuer, generally excludable from gross income for Federal income tax purposes (except that the interest may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">includable in taxable income for purposes of the Federal alternative minimum tax). Municipal bonds may be obligations </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of a variety of issuers, including governmental entities or other qualifying issuers. Issuers may be states, territories </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and possessions of the United States and the District of Columbia and their political subdivisions, agencies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">instrumentalities. Municipal bonds also include short-term tax-exempt obligations like municipal notes and variable </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate demand obligations.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may invest in municipal bonds rated in any rating category or in unrated municipal bonds. Fund management </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">presently intends to invest at least 65% of the Fund’s net assets in municipal bonds rated investment grade or in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">unrated municipal bonds that Fund management believes are of comparable quality. Investment grade bonds are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">securities which are rated in the four highest categories by at least one of the major rating agencies or determined by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the management team to be of similar quality. The Fund does not intend to invest more than 35% of its net assets in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">junk bonds or in unrated bonds that Fund management believes are of comparable quality. This is a non-fundamental </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policy and may be changed by the Board at any time. The Fund will primarily invest in municipal bonds that have a </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">maturity of five years or longer.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may engage in transactions in certain derivatives, such as financial futures contracts and options thereon, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">indexed and inverse floating rate obligations and swap agreements, including credit default swap agreements. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund may use derivative instruments to hedge its investments (including anticipatory hedges) or to seek to enhance </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">returns. The Fund may leverage its assets through the use of proceeds received through tender option bond </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">transactions. In a tender option bond transaction, the Fund transfers municipal bonds or other municipal securities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">into a special purpose entity (a “TOB Trust”). A TOB Trust typically issues two classes of beneficial interests: short-term</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> floating rate interests (“TOB Floaters”), which are sold to third party investors, and residual inverse floating rate </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">interests (“TOB Residuals”), which are generally issued to the Fund. The Fund may invest in TOB Residuals and may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">also invest in TOB Floaters. The Fund will look through to the underlying municipal bond held by a TOB Trust for </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">purposes of the Fund’s 80% policy.</span></div> Under normal circumstances, the National Fund seeks to achieve its objective by investing at least 80% of its net assets, plus the amount of any borrowing for investment purposes, in municipal bonds and derivatives that provide investment exposure to such securities or to one or more market risk factors associated with such securities. <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may invest in municipal bonds rated in any rating category or in unrated municipal bonds. Fund management </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">presently intends to invest at least 65% of the Fund’s net assets in municipal bonds rated investment grade or in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">unrated municipal bonds that Fund management believes are of comparable quality. Investment grade bonds are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">securities which are rated in the four highest categories by at least one of the major rating agencies or determined by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the management team to be of similar quality. The Fund does not intend to invest more than 35% of its net assets in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">junk bonds or in unrated bonds that Fund management believes are of comparable quality. This is a non-fundamental </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policy and may be changed by the Board at any time. The Fund will primarily invest in municipal bonds that have a </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">maturity of five years or longer.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may engage in transactions in certain derivatives, such as financial futures contracts and options thereon, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">indexed and inverse floating rate obligations and swap agreements, including credit default swap agreements. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund may use derivative instruments to hedge its investments (including anticipatory hedges) or to seek to enhance </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">returns. The Fund may leverage its assets through the use of proceeds received through tender option bond </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">transactions. In a tender option bond transaction, the Fund transfers municipal bonds or other municipal securities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">into a special purpose entity (a “TOB Trust”). A TOB Trust typically issues two classes of beneficial interests: short-term</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> floating rate interests (“TOB Floaters”), which are sold to third party investors, and residual inverse floating rate </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">interests (“TOB Residuals”), which are generally issued to the Fund. The Fund may invest in TOB Residuals and may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">also invest in TOB Floaters. The Fund will look through to the underlying municipal bond held by a TOB Trust for </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">purposes of the Fund’s 80% policy.</span></div> You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Debt Securities Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Debt securities, such as bonds, involve risks, such as credit risk, interest rate risk, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">extension risk, and prepayment risk, each of which are described in further detail below:</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Credit Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Credit risk refers to the possibility that the issuer of a debt security (i.e., the borrower) will not be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">able to make payments of interest and principal when due. Changes in an issuer’s credit rating or the market’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Interest Rate Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The market value of bonds and other fixed-income securities changes in response to interest </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate changes and other factors. Interest rate risk is the risk that prices of bonds and other fixed-income securities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">will increase as interest rates fall and decrease as interest rates rise.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may be subject to a greater risk of rising interest rates during a period of low interest rates. For example, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">if interest rates increase by 1%, assuming a current portfolio duration of ten years, and all other factors being </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">equal, the value of the Fund’s investments would be expected to decrease by 10%. (Duration is a measure of the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">price sensitivity of a debt security or portfolio of debt securities to relative changes in interest rates.) The magnitude </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of these fluctuations in the market price of bonds and other fixed-income securities is generally greater for those </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">securities with longer maturities. Fluctuations in the market price of the Fund’s investments will not affect interest </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">income derived from instruments already owned by the Fund, but will be reflected in the Fund’s net asset value. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund may lose money if short-term or long-term interest rates rise sharply in a manner not anticipated by Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">management.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">To the extent the Fund invests in debt securities that may be prepaid at the option of the obligor (such as mortgage-backed</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> securities), the sensitivity of such securities to changes in interest rates may increase (to the detriment of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund) when interest rates rise. Moreover, because rates on certain floating rate debt securities typically reset </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">only periodically, changes in prevailing interest rates (and particularly sudden and significant changes) can be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">expected to cause some fluctuations in the net asset value of the Fund to the extent that it invests in floating rate </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">debt securities.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">These basic principles of bond prices also apply to U.S. Government securities. A security backed by the “full faith </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and credit” of the U.S. Government is guaranteed only as to its stated interest rate and face value at maturity, not </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">its current market price. Just like other fixed-income securities, government-guaranteed securities will fluctuate in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">value when interest rates change.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">A general rise in interest rates has the potential to cause investors to move out of fixed-income securities on a large </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">scale, which may increase redemptions from funds that hold large amounts of fixed-income securities. Heavy </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">redemptions could cause the Fund to sell assets at inopportune times or at a loss or depressed value and could </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">hurt the Fund’s performance.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Extension Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — When interest rates rise, certain obligations will be paid off by the obligor more slowly than </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">anticipated, causing the value of these obligations to fall.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Prepayment Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — When interest rates fall, certain obligations will be paid off by the obligor more quickly than </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">originally anticipated, and the Fund may have to invest the proceeds in securities with lower yields.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Municipal Securities Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Municipal securities risks include the ability of the issuer to repay the obligation, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">relative lack of information about certain issuers of municipal securities, and the possibility of future legislative </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">changes which could affect the market for and value of municipal securities. Budgetary constraints of local, state, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and federal governments upon which the issuers may be relying for funding may also impact municipal securities. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">These risks include:</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">General Obligation Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Timely payments depend on the issuer’s credit quality, ability to raise tax </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">revenues and ability to maintain an adequate tax base.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Revenue Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> These payments depend on the money earned by the particular facility or class of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">facilities, or the amount of revenues derived from another source.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Private Activity Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Municipalities and other public authorities issue private activity bonds to finance </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">development of industrial facilities for use by a private enterprise. The private enterprise pays the principal and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">interest on the bond, and the issuer does not pledge its full faith, credit and taxing power for repayment.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Moral Obligation Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Moral obligation bonds are generally issued by special purpose public authorities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of a state or municipality. If the issuer is unable to meet its obligations, repayment of these bonds becomes a moral </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">commitment, but not a legal obligation, of the state or municipality.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Municipal Notes Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Municipal notes are shorter term municipal debt obligations. If there is a shortfall in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">anticipated proceeds, the notes may not be fully repaid and the Fund may lose money.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Municipal Lease Obligations Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> In a municipal lease obligation, the issuer agrees to make payments when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">due on the lease obligation. Although the issuer does not pledge its unlimited taxing power for payment of the lease </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">obligation, the lease obligation is secured by the leased property.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Tax-Exempt Status Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The Fund and its investment manager will rely on the opinion of issuers’ bond counsel </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and, in the case of derivative securities, sponsors’ counsel, on the tax-exempt status of interest on municipal bonds </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and payments under derivative securities. Neither the Fund nor its investment manager will independently review the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">bases for those tax opinions, which may ultimately be determined to be incorrect and subject the Fund and its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shareholders to substantial tax liabilities.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">High Yield Bonds Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Although junk bonds generally pay higher rates of interest than investment grade bonds, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">junk bonds are high risk investments that are considered speculative and may cause income and principal losses </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the Fund.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.0pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Derivatives Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund’s use of derivatives may increase its costs, reduce the Fund’s returns and/or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">increase volatility. Derivatives involve significant risks, including:</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Leverage Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund’s use of derivatives can magnify the Fund’s gains and losses. Relatively small market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">movements may result in large changes in the value of a derivatives position and can result in losses that greatly </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">exceed the amount originally invested.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Market Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Some derivatives are more sensitive to interest rate changes and market price fluctuations than </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">other securities. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">market movements, which losses are potentially unlimited. Finally, BlackRock may not be able to predict correctly </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the direction of securities prices, interest rates and other economic factors, which could cause the Fund’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">derivatives positions to lose value.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Counterparty Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Derivatives are also subject to counterparty risk, which is the risk that the other party in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">transaction will be unable or unwilling to fulfill its contractual obligation, and the related risks of having concentrated </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">exposure to such a counterparty.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Illiquidity Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">difficult for the Fund to value accurately.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Operational Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The use of derivatives includes the risk of potential operational issues, including documentation </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">issues, settlement issues, systems failures, inadequate controls and human error.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Legal Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The risk of insufficient documentation, insufficient capacity or authority of counterparty, or legality or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">enforceability of a contract.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Volatility and Correlation Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Volatility is defined as the characteristic of a security, an index or a market to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">fluctuate significantly in price within a short time period. A risk of the Fund’s use of derivatives is that the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">fluctuations in their values may not correlate with the overall securities markets.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Valuation Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Valuation for derivatives may not be readily available in the market. Valuation may be more difficult </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">in times of market turmoil since many investors and market makers may be reluctant to purchase complex </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">instruments or quote prices for them.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Hedging Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Hedges are sometimes subject to imperfect matching between the derivative and the underlying </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">security, and there can be no assurance that the Fund’s hedging transactions will be effective. The use of hedging </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may result in certain adverse tax consequences.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Tax Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Certain aspects of the tax treatment of derivative instruments, including swap agreements and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">commodity-linked derivative instruments, are currently unclear and may be affected by changes in legislation, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">regulations or other legally binding authority. Such treatment may be less favorable than that given to a direct </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment in an underlying asset and may adversely affect the timing, character and amount of income the Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">realizes from its investments.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Regulatory Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Derivative contracts are subject to regulation under the Dodd-Frank Wall Street Reform and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Consumer Protection Act (the “Dodd-Frank Act”) in the United States and under comparable regimes in Europe, Asia </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and other non-U.S. jurisdictions. Under the Dodd-Frank Act, with respect to uncleared swaps, swap dealers are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">required to exchange variation margin with the Fund and may be required by applicable regulations to collect and/or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">exchange initial margin with the Fund. Both initial and variation margin may be comprised of cash and/or securities, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">subject to applicable regulatory haircuts. In certain cases, shares of investment companies may not be posted as </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">collateral under applicable regulations. In addition, regulations adopted by global prudential regulators require </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">certain bank-regulated counterparties and certain of their affiliates to include in certain financial contracts, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">including many derivatives contracts, terms that delay or restrict the rights of counterparties, such as the Fund, to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">terminate such contracts, foreclose upon collateral, exercise other default rights or restrict transfers of credit </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">support in the event that the counterparty and/or its affiliates are subject to certain types of resolution or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">insolvency proceedings. The implementation of these requirements with respect to derivatives, as well as </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">regulations under global regulations regarding clearing, mandatory trading and margining of other derivatives, may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">increase the costs and risks to the Fund of trading in these instruments and, as a result, may affect returns to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investors in the Fund. Future regulatory developments may impact the Fund’s ability to invest or remain invested in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">certain derivatives. Legislation or regulation may also change the way in which the Fund itself is regulated. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">BlackRock cannot predict the effects of any new governmental regulation that may be implemented on the ability of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund to use swaps or any other financial derivative product, and there can be no assurance that any new </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">governmental regulation will not adversely affect the Fund’s ability to achieve its investment objective.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Illiquid Investments Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund may not acquire any illiquid investment if, immediately after the acquisition, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund would have invested more than 15% of its net assets in illiquid investments. An illiquid investment is any </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">calendar days or less without the sale or disposition significantly changing the market value of the investment. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Liquid investments may become illiquid after purchase by the Fund, particularly during periods of market turmoil. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">There can be no assurance that a security or instrument that is deemed to be liquid when purchased will continue </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to be liquid for as long as it is held by the Fund, and any security or instrument held by the Fund may be deemed an </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">illiquid investment pursuant to the Fund’s liquidity risk management program. The Fund’s illiquid investments may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">reduce the returns of the Fund because it may be difficult to sell the illiquid investments at an advantageous time </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or price. In addition, if the Fund is limited in its ability to dispose of illiquid investments during periods when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shareholders are redeeming or selling their shares or the Fund’s net assets otherwise shrink, the Fund will need to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">dispose of liquid securities to meet redemption requests and illiquid securities will become a larger portion of the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund’s holdings. An investment may be illiquid due to, among other things, the reduced number and capacity of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">traditional market participants to make a market in fixed-income securities or the lack of an active trading market. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">To the extent that the Fund’s principal investment strategies involve derivatives or securities with substantial market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and/or credit risk, the Fund will tend to have greater exposure to the risks associated with illiquid investments. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Illiquid investments may be harder to value, especially in changing markets, and if the Fund is forced to sell these </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investments to meet redemption requests or for other cash needs, the Fund may suffer a loss. This may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">magnified in a rising interest rate environment or other circumstances where investor redemptions or sales of Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shares may be higher than normal. In addition, when there is illiquidity in the market for certain securities, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund, due to limitations on illiquid investments, may be subject to purchase and sale restrictions.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Leverage Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Some transactions may give rise to a form of economic leverage. These transactions may include, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">among others, derivatives, and may expose the Fund to greater risk and increase its costs. The use of leverage may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to meet the applicable requirements of the Investment Company Act of 1940, as amended (the “Investment </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Company Act”), and the rules thereunder. Increases and decreases in the value of the Fund’s portfolio will be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">magnified when the Fund uses leverage.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.0pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Market Risk and Selection Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Market risk is the risk that one or more markets in which the Fund invests will </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">go down in value, including the possibility that the markets will go down sharply and unpredictably. An investor could </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">lose money over short periods due to fluctuation in the Fund’s net asset value in response to short-term market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">movements and over longer periods during market downturns. Securities or other investments held by the Fund may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">underperform the markets, the relevant indices or benchmarks, or the securities selected by other funds with </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">similar investment objectives and investment strategies, or may otherwise fail to perform as intended. The value of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">a security or other asset may decline due to changes in general market conditions, economic trends or events that </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">are not specifically related to the issuer of the security or other asset, or factors that affect a particular issuer or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">issuers, exchange, country, group of countries, region, market, industry, group of industries, sector or asset class. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The success of the Fund’s activities could be affected by interest rates, availability of credit, inflation rates, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">economic uncertainty, changes in laws, tariffs and trade barriers, supply chain disruptions, economic sanctions, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">currency exchange controls, and local, regional or global events such as war, acts of terrorism, natural and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">environmental disasters, the spread of infectious illness or other public health issues, recessions, or other events.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Recent policy initiatives undertaken by the U.S. government have the potential to impact international relations, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">trade agreements and the overall regulatory environment in ways that could create uncertainty and instability in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">domestic and global markets, and could adversely affect the investment performance of the Fund. In particular, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">actions taken by the U.S. government in respect of international trade relations could lead to trade wars, increased </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">costs for imported goods, disruptions in supply chains, reduced foreign investment, and instability in regions where </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund invests.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Operational and Technology Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund is directly and indirectly susceptible to operational and technology </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">risks, including those related to human errors, processing errors, communication errors, systems failures, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">cybersecurity incidents, and the use of artificial intelligence and machine learning (“AI”), which may result in losses </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the Fund and its shareholders or may impair the Fund’s operations. While the Fund’s service providers are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">required to have appropriate operational, information security and cybersecurity risk management policies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">procedures, their methods of risk management may differ from those of the Fund. Operational and technology risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the issuers in which the Fund invests could also result in material adverse consequences for such issuers and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may cause the Fund’s investments in such issuers to lose value.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Tender Option Bonds and Related Securities Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund’s participation in tender option bond transactions </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may reduce the Fund’s returns and/or increase volatility. Investments in tender option bond transactions expose the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund to counterparty risk and leverage risk. An investment in a tender option bond transaction typically will involve </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">greater risk than an investment in a municipal fixed rate security, including the risk of loss of principal. Distributions </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">on TOB Residuals will bear an inverse relationship to short-term municipal security interest rates. Distributions on </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">TOB Residuals paid to the Fund will be reduced or, in the extreme, eliminated as short-term municipal interest rates </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rise and will increase when short-term municipal interest rates fall. TOB Residuals generally will underperform the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">market for fixed rate municipal securities in a rising interest rate environment. The Fund may invest in TOB Trusts on </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">either a non-recourse or recourse basis. If the Fund invests in a TOB Trust on a recourse basis, it could suffer </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">losses in excess of the value of its TOB Residuals.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Variable Rate Demand Obligations Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Variable rate demand obligations are floating rate securities that </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">combine an interest in a long-term municipal bond with a right to demand payment before maturity from a bank or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">other financial institution. If the bank or financial institution is unable to pay, the Fund may lose money.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> Performance Information <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The information shows you how the Fund’s performance has varied year by year and provides some indication of the</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> risks of investing in the Fund. The table compares the Fund’s performance to that of the Bloomberg Municipal Bond </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Index. Effective August 15, 2016, the Board of Directors of the Corporation approved the reclassification of BlackRock </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Shares of the Fund as Class K Shares. The returns for Class K Shares prior to August 15, 2016 reflects the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">performance of the share class when it was classified as BlackRock Shares. To the extent that dividends and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">distributions have been paid by the Fund, the performance information for the Fund in the chart and table assumes </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">reinvestment of the dividends and distributions. As with all such investments, past performance (before and after</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> taxes) is not an indication of future results. The table includes all applicable fees. If the Fund’s investment manager </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund’s returns would </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">have been lower. Updated information on the Fund’s performance, including its current net asset value, can be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">obtained by visiting www.blackrock.com or can be obtained by phone at </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">(800) 882-0052</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">.</span></div> The information shows you how the Fund’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance (before and after taxes) is not an indication of future results. www.blackrock.com (800) 882-0052 Class K Shares ANNUAL TOTAL RETURNS BlackRock National Municipal Fund As of 12/31 <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">During the ten-year period shown in the bar chart, the highest return for a quarter was 5.94% (quarter ended </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">December 31, 2023) and the lowest return for a quarter was -6.12% (quarter ended March 31, 2022). The year-to-date return as of September 30, 2026 was -3.12%.</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> highest return 0.0594 2023-12-31 lowest return -0.0612 2022-03-31 year-to-date return 2026-09-30 -0.0312 For the periods ended 12/31/25Average Annual Total Returns 0.0330 0.0057 0.0208 0.0330 0.0054 0.0206 0.0353 0.0111 0.0228 0.0425 0.0080 0.0234 <div style="margin-top: 12pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. Fund Overview Key Facts About BlackRock Short Duration Muni Fund Investment Objective <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The investment objective of BlackRock Short Duration Muni Fund (formerly, BlackRock Short-Term Municipal Fund) (the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">“</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Short Duration Fund</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">” </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or the “Fund”) is to provide shareholders with as high a level of income exempt from Federal </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">income taxes as is consistent with the investment policies of the Fund.</span></div> Fees and Expenses of the Fund <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">This table describes the fees and expenses that you may pay if you buy, hold and sell Class K Shares of the Fund. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Amounts in the table are rounded to the nearest basis point, which in some cases may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">“</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">0.00.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">”</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">You may pay other </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">fees, such as brokerage commissions and other fees to your financial professional or your selected securities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">dealer, broker, investment adviser, service provider or industry professional (including BlackRock Advisors, LLC </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">(“BlackRock”) and its affiliates) (each a “Financial Intermediary”), which are not reflected in the table and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">example below.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) 0.0029 0 0.0009 0.0001 0.0039 -0.0007 0.0032 June 30, 2028 Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent Annual Financial Statements and Additional Information, which does not include Acquired Fund Fees and Expenses. Example: <div style="line-height: 10.695pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or lower, based on these assumptions your costs would be:</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> 33 118 212 486 Portfolio Turnover: <div style="line-height: 10.695pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">44</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">% of the average value of its portfolio.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> 0.44 Principal Investment Strategies of the Fund <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Under normal circumstances, the Short Duration Fund seeks to achieve its objective by investing at least 80% of its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">net assets, plus the amount of any borrowing for investment purposes, in municipal bonds and derivatives that provide </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment exposure to such securities or to one or more market risk factors associated with such securities. This </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policy is a fundamental policy of the Fund and may not be changed without approval of a majority of the Fund’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">outstanding securities, as defined in the Investment Company Act. Municipal bonds include debt obligations issued by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or on behalf of a governmental entity or other qualifying issuer that pay interest that is, in the opinion of bond counsel </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to the issuer, generally excludable from gross income for Federal income tax purposes (except that the interest may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">includable in taxable income for purposes of the Federal alternative minimum tax). Municipal bonds may be obligations </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of a variety of issuers, including governmental entities or other qualifying issuers. Issuers may be states, territories </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and possessions of the United States and the District of Columbia and their political subdivisions, agencies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">instrumentalities. Municipal bonds also include short-term tax-exempt obligations like municipal notes and variable </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate demand obligations.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Under normal circumstances, the Short Duration Fund seeks to achieve its objective by investing at least 80% of its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">net assets, plus the amount of any borrowing for investment purposes, in municipal bonds and derivatives that provide </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment exposure to such securities or to one or more market risk factors associated with such securities. This </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policy is a fundamental policy of the Fund and may not be changed without approval of a majority of the Fund’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">outstanding securities, as defined in the Investment Company Act. Municipal bonds include debt obligations issued by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or on behalf of a governmental entity or other qualifying issuer that pay interest that is, in the opinion of bond counsel </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to the issuer, generally excludable from gross income for Federal income tax purposes (except that the interest may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">includable in taxable income for purposes of the Federal alternative minimum tax). Municipal bonds may be obligations </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of a variety of issuers, including governmental entities or other qualifying issuers. Issuers may be states, territories </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and possessions of the United States and the District of Columbia and their political subdivisions, agencies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">instrumentalities. Municipal bonds also include short-term tax-exempt obligations like municipal notes and variable </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate demand obligations.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Short Duration Fund invests primarily in investment grade municipal bonds or municipal notes, including variable </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate demand obligations. Investment grade bonds are securities which are rated in the four highest categories by at </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">least one of the major rating agencies or determined by the management team to be of similar quality. Generally, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">higher the rating of a bond, the higher the likelihood that interest and principal payments will be made on time. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Municipal notes are shorter-term municipal debt obligations that pay interest that is, in the opinion of bond counsel to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the issuer, generally excludable from gross income for Federal income tax purposes (except that the interest may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">includable in taxable income for purposes of the Federal alternative minimum tax) and that have a maturity that is </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">generally one year or less.</span></div> <div style="margin-top: 7pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Under normal circumstances, the effective duration of the Fund’s portfolio is expected to be 4 years or less, as </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">calculated by the Fund’s management team. Effective duration is a measure of the Fund’s price sensitivity to changes </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">in yields or interest rates; however, investors should be aware that effective duration is not an exact measurement and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may not reliably predict a particular security’s price sensitivity to changes in yield or interest rates.</span></div> Under normal circumstances, the Short Duration Fund seeks to achieve its objective by investing at least 80% of its net assets, plus the amount of any borrowing for investment purposes, in municipal bonds and derivatives that provide investment exposure to such securities or to one or more market risk factors associated with such securities. <div style="margin-top: 7pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Under normal circumstances, the effective duration of the Fund’s portfolio is expected to be 4 years or less, as </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">calculated by the Fund’s management team. Effective duration is a measure of the Fund’s price sensitivity to changes </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">in yields or interest rates; however, investors should be aware that effective duration is not an exact measurement and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may not reliably predict a particular security’s price sensitivity to changes in yield or interest rates.</span></div> You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Debt Securities Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Debt securities, such as bonds, involve risks, such as credit risk, interest rate risk, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">extension risk, and prepayment risk, each of which are described in further detail below:</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Credit Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Credit risk refers to the possibility that the issuer of a debt security (i.e., the borrower) will not be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">able to make payments of interest and principal when due. Changes in an issuer’s credit rating or the market’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Interest Rate Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The market value of bonds and other fixed-income securities changes in response to interest </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate changes and other factors. Interest rate risk is the risk that prices of bonds and other fixed-income securities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">will increase as interest rates fall and decrease as interest rates rise.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may be subject to a greater risk of rising interest rates during a period of low interest rates. For example, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">if interest rates increase by 1%, assuming a current portfolio duration of ten years, and all other factors being </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">equal, the value of the Fund’s investments would be expected to decrease by 10%. (Duration is a measure of the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">price sensitivity of a debt security or portfolio of debt securities to relative changes in interest rates.) The magnitude </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of these fluctuations in the market price of bonds and other fixed-income securities is generally greater for those </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">securities with longer maturities. Fluctuations in the market price of the Fund’s investments will not affect interest </span></div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">income derived from instruments already owned by the Fund, but will be reflected in the Fund’s net asset value. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund may lose money if short-term or long-term interest rates rise sharply in a manner not anticipated by Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">management.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">To the extent the Fund invests in debt securities that may be prepaid at the option of the obligor (such as mortgage-backed</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> securities), the sensitivity of such securities to changes in interest rates may increase (to the detriment of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund) when interest rates rise. Moreover, because rates on certain floating rate debt securities typically reset </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">only periodically, changes in prevailing interest rates (and particularly sudden and significant changes) can be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">expected to cause some fluctuations in the net asset value of the Fund to the extent that it invests in floating rate </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">debt securities.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">These basic principles of bond prices also apply to U.S. Government securities. A security backed by the “full faith </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and credit” of the U.S. Government is guaranteed only as to its stated interest rate and face value at maturity, not </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">its current market price. Just like other fixed-income securities, government-guaranteed securities will fluctuate in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">value when interest rates change.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">A general rise in interest rates has the potential to cause investors to move out of fixed-income securities on a large </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">scale, which may increase redemptions from funds that hold large amounts of fixed-income securities. Heavy </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">redemptions could cause the Fund to sell assets at inopportune times or at a loss or depressed value and could </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">hurt the Fund’s performance.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Extension Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — When interest rates rise, certain obligations will be paid off by the obligor more slowly than </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">anticipated, causing the value of these obligations to fall.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Prepayment Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — When interest rates fall, certain obligations will be paid off by the obligor more quickly than </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">originally anticipated, and the Fund may have to invest the proceeds in securities with lower yields.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Municipal Securities Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Municipal securities risks include the ability of the issuer to repay the obligation, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">relative lack of information about certain issuers of municipal securities, and the possibility of future legislative </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">changes which could affect the market for and value of municipal securities. Budgetary constraints of local, state, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and federal governments upon which the issuers may be relying for funding may also impact municipal securities. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">These risks include:</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">General Obligation Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Timely payments depend on the issuer’s credit quality, ability to raise tax </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">revenues and ability to maintain an adequate tax base.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Revenue Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> These payments depend on the money earned by the particular facility or class of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">facilities, or the amount of revenues derived from another source.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Private Activity Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Municipalities and other public authorities issue private activity bonds to finance </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">development of industrial facilities for use by a private enterprise. The private enterprise pays the principal and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">interest on the bond, and the issuer does not pledge its full faith, credit and taxing power for repayment.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Moral Obligation Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Moral obligation bonds are generally issued by special purpose public authorities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of a state or municipality. If the issuer is unable to meet its obligations, repayment of these bonds becomes a moral </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">commitment, but not a legal obligation, of the state or municipality.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Municipal Notes Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Municipal notes are shorter term municipal debt obligations. If there is a shortfall in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">anticipated proceeds, the notes may not be fully repaid and the Fund may lose money.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Municipal Lease Obligations Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> In a municipal lease obligation, the issuer agrees to make payments when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">due on the lease obligation. Although the issuer does not pledge its unlimited taxing power for payment of the lease </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">obligation, the lease obligation is secured by the leased property.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Tax-Exempt Status Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The Fund and its investment manager will rely on the opinion of issuers’ bond counsel </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and, in the case of derivative securities, sponsors’ counsel, on the tax-exempt status of interest on municipal bonds </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and payments under derivative securities. Neither the Fund nor its investment manager will independently review the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">bases for those tax opinions, which may ultimately be determined to be incorrect and subject the Fund and its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shareholders to substantial tax liabilities.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.0pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Market Risk and Selection Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Market risk is the risk that one or more markets in which the Fund invests will </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">go down in value, including the possibility that the markets will go down sharply and unpredictably. An investor could </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">lose money over short periods due to fluctuation in the Fund’s net asset value in response to short-term market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">movements and over longer periods during market downturns. Securities or other investments held by the Fund may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">underperform the markets, the relevant indices or benchmarks, or the securities selected by other funds with </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">similar investment objectives and investment strategies, or may otherwise fail to perform as intended. The value of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">a security or other asset may decline due to changes in general market conditions, economic trends or events that </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">are not specifically related to the issuer of the security or other asset, or factors that affect a particular issuer or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">issuers, exchange, country, group of countries, region, market, industry, group of industries, sector or asset class. </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The success of the Fund’s activities could be affected by interest rates, availability of credit, inflation rates, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">economic uncertainty, changes in laws, tariffs and trade barriers, supply chain disruptions, economic sanctions, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">currency exchange controls, and local, regional or global events such as war, acts of terrorism, natural and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">environmental disasters, the spread of infectious illness or other public health issues, recessions, or other events.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Recent policy initiatives undertaken by the U.S. government have the potential to impact international relations, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">trade agreements and the overall regulatory environment in ways that could create uncertainty and instability in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">domestic and global markets, and could adversely affect the investment performance of the Fund. In particular, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">actions taken by the U.S. government in respect of international trade relations could lead to trade wars, increased </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">costs for imported goods, disruptions in supply chains, reduced foreign investment, and instability in regions where </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund invests.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Illiquid Investments Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund may not acquire any illiquid investment if, immediately after the acquisition, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund would have invested more than 15% of its net assets in illiquid investments. An illiquid investment is any </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">calendar days or less without the sale or disposition significantly changing the market value of the investment. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Liquid investments may become illiquid after purchase by the Fund, particularly during periods of market turmoil. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">There can be no assurance that a security or instrument that is deemed to be liquid when purchased will continue </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to be liquid for as long as it is held by the Fund, and any security or instrument held by the Fund may be deemed an </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">illiquid investment pursuant to the Fund’s liquidity risk management program. The Fund’s illiquid investments may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">reduce the returns of the Fund because it may be difficult to sell the illiquid investments at an advantageous time </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or price. In addition, if the Fund is limited in its ability to dispose of illiquid investments during periods when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shareholders are redeeming or selling their shares or the Fund’s net assets otherwise shrink, the Fund will need to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">dispose of liquid securities to meet redemption requests and illiquid securities will become a larger portion of the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund’s holdings. An investment may be illiquid due to, among other things, the reduced number and capacity of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">traditional market participants to make a market in fixed-income securities or the lack of an active trading market. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">To the extent that the Fund’s principal investment strategies involve derivatives or securities with substantial market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and/or credit risk, the Fund will tend to have greater exposure to the risks associated with illiquid investments. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Illiquid investments may be harder to value, especially in changing markets, and if the Fund is forced to sell these </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investments to meet redemption requests or for other cash needs, the Fund may suffer a loss. This may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">magnified in a rising interest rate environment or other circumstances where investor redemptions or sales of Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shares may be higher than normal. In addition, when there is illiquidity in the market for certain securities, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund, due to limitations on illiquid investments, may be subject to purchase and sale restrictions.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Leverage Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Some transactions may give rise to a form of economic leverage. These transactions may include, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">among others, derivatives, and may expose the Fund to greater risk and increase its costs. The use of leverage may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to meet the applicable requirements of the Investment Company Act of 1940, as amended (the “Investment </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Company Act”), and the rules thereunder. Increases and decreases in the value of the Fund’s portfolio will be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">magnified when the Fund uses leverage.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Operational and Technology Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund is directly and indirectly susceptible to operational and technology </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">risks, including those related to human errors, processing errors, communication errors, systems failures, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">cybersecurity incidents, and the use of artificial intelligence and machine learning (“AI”), which may result in losses </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the Fund and its shareholders or may impair the Fund’s operations. While the Fund’s service providers are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">required to have appropriate operational, information security and cybersecurity risk management policies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">procedures, their methods of risk management may differ from those of the Fund. Operational and technology risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the issuers in which the Fund invests could also result in material adverse consequences for such issuers and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may cause the Fund’s investments in such issuers to lose value.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Variable Rate Demand Obligations Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">—</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Variable rate demand obligations are floating rate securities that </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">combine an interest in a long term municipal bond with a right to demand payment before maturity from a bank or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">other financial institution. If the bank or financial institution is unable to pay, the Fund may lose money.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> Performance Information <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The information shows you how the Fund’s performance has varied year by year and provides some indication of the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">risks of investing in the Fund. The table compares the Fund’s performance to that of the Bloomberg Municipal Bond </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Index and the Bloomberg Municipal 1-5 Year Index. Fund management believes the Short-Term Customized Reference </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Benchmark no longer has characteristics similar to the current investment strategy of the Fund. To the extent that </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">dividends and distributions have been paid by the Fund, the performance information for the Fund in the chart and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">table assumes reinvestment of the dividends and distributions. As with all such investments, past performance </span></div> <div style="line-height: 10.695pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">(before and after taxes) is not an indication of future results. The table includes all applicable fees. If the Fund’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment manager and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund’s returns would have been lower. Updated information on the Fund’s performance, including its current net asset </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">value, can be obtained by visiting www.blackrock.com or can be obtained by phone at </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">(800) 882-0052</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">.</span></div> The information shows you how the Fund’s performance has varied year by year and provides some indication of the risks of investing in the Fund. The table compares the Fund’s performance to that of the Bloomberg Municipal Bond Index and the Bloomberg Municipal 1-5 Year Index. Fund management believes the Short-Term Customized Reference Benchmark no longer has characteristics similar to the current investment strategy of the Fund. As with all such investments, past performance(before and after taxes) is not an indication of future results.  www.blackrock.com (800) 882-0052 Class K Shares ANNUAL TOTAL RETURNS BlackRock Short Duration Muni Fund As of 12/31 <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">During the ten-year period shown in the bar chart, the highest return for a quarter was 3.35% (quarter ended </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">December 31, 2023) and the lowest return for a quarter was -2.61% (quarter ended March 31, 2022). The year-to-date return</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> as of September 30, 2026 was -1.26%.</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> highest return 0.0335 2023-12-31 lowest return -0.0261 2022-03-31 year-to-date return 2026-09-30 -0.0126 For the periods ended 12/31/25Average Annual Total Returns 0.0520 0.0199 0.0163 0.0520 0.0199 0.0163 0.0456 0.0206 0.0165 0.0425 0.0080 0.0234 0.0411 0.0136 0.0167 <div style="margin-top: 12pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. Fund Overview Key Facts About BlackRock National Municipal Fund Investment Objective <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The investment objective of BlackRock National Municipal Fund (the “Fund”) is to provide shareholders with as high a </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">level of income exempt from Federal income taxes as is consistent with the investment policies of the Fund.</span></div> Fees and Expenses of the Fund <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">This table describes the fees and expenses that you may pay if you buy, hold and sell Service Shares of the Fund. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Amounts in the table are rounded to the nearest basis point, which in some cases may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">“</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">0.00.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">”</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">You may pay other </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">fees, such as brokerage commissions and other fees to your financial professional or your selected securities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">dealer, broker, investment adviser, service provider or industry professional (including BlackRock Advisors, LLC </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">(“BlackRock”) and its affiliates) (each a “Financial Intermediary”), which are not reflected in the table and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-weight: bold;">example below.</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) 0.0039 0.0025 0.0021 0.0015 0.0006 0.0001 0.0086 -0.0011 0.0075 June 30, 2028 The Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent Annual Financial Statements and Additional Information, which do not include Acquired Fund Fees and Expenses. Example: <div style="line-height: 10.695pt; margin-top: 0.0pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or lower, based on these assumptions your costs would be:</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> 77 263 466 1051 Portfolio Turnover: <div style="line-height: 10.695pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">54</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">% of the average value of its portfolio.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> 0.54 Principal Investment Strategies of the Fund <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Under normal circumstances, the Fund seeks to achieve its objective by investing at least 80% of its net assets, plus</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> the amount of any borrowing for investment purposes, in municipal bonds and derivatives that provide investment</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> exposure to such securities or to one or more market risk factors associated with such securities. This policy is a </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">fundamental policy of the Fund and may not be changed without approval of a majority of the Fund’s outstanding </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">securities, as defined in the Investment Company Act. Municipal bonds include debt obligations issued by or on behalf </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of a governmental entity or other qualifying issuer that pay interest that is, in the opinion of bond counsel to the issuer, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">generally excludable from gross income for Federal income tax purposes (except that the interest may be includable in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">taxable income for purposes of the Federal alternative minimum tax). Municipal bonds may be obligations of a variety </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of issuers, including governmental entities or other qualifying issuers. Issuers may be states, territories and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">possessions of the United States and the District of Columbia and their political subdivisions, agencies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">instrumentalities. Municipal bonds also include short-term tax-exempt obligations like municipal notes and variable </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate demand obligations.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may invest in municipal bonds rated in any rating category or in unrated municipal bonds. Fund management </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">presently intends to invest at least 65% of the Fund’s net assets in municipal bonds rated investment grade or in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">unrated municipal bonds that Fund management believes are of comparable quality. Investment grade bonds are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">securities which are rated in the four highest categories by at least one of the major rating agencies or determined by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the management team to be of similar quality. The Fund does not intend to invest more than 35% of its net assets in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">junk bonds or in unrated bonds that Fund management believes are of comparable quality. This is a non-fundamental </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policy and may be changed by the Board at any time. The Fund will primarily invest in municipal bonds that have a </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">maturity of five years or longer.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may engage in transactions in certain derivatives, such as financial futures contracts and options thereon, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">indexed and inverse floating rate obligations and swap agreements, including credit default swap agreements. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund may use derivative instruments to hedge its investments (including anticipatory hedges) or to seek to enhance </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">returns. The Fund may leverage its assets through the use of proceeds received through tender option bond </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">transactions. In a tender option bond transaction, the Fund transfers municipal bonds or other municipal securities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">into a special purpose entity (a “TOB Trust”). A TOB Trust typically issues two classes of beneficial interests: short-term</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> floating rate interests (“TOB Floaters”), which are sold to third party investors, and residual inverse floating rate </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">interests (“TOB Residuals”), which are generally issued to the Fund. The Fund may invest in TOB Residuals and may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">also invest in TOB Floaters. The Fund will look through to the underlying municipal bond held by a TOB Trust for </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">purposes of the Fund’s 80% policy.</span></div> Under normal circumstances, the Fund seeks to achieve its objective by investing at least 80% of its net assets, plus the amount of any borrowing for investment purposes, in municipal bonds and derivatives that provide investment exposure to such securities or to one or more market risk factors associated with such securities. <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may invest in municipal bonds rated in any rating category or in unrated municipal bonds. Fund management </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">presently intends to invest at least 65% of the Fund’s net assets in municipal bonds rated investment grade or in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">unrated municipal bonds that Fund management believes are of comparable quality. Investment grade bonds are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">securities which are rated in the four highest categories by at least one of the major rating agencies or determined by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the management team to be of similar quality. The Fund does not intend to invest more than 35% of its net assets in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">junk bonds or in unrated bonds that Fund management believes are of comparable quality. This is a non-fundamental </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policy and may be changed by the Board at any time. The Fund will primarily invest in municipal bonds that have a </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">maturity of five years or longer.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may engage in transactions in certain derivatives, such as financial futures contracts and options thereon, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">indexed and inverse floating rate obligations and swap agreements, including credit default swap agreements. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund may use derivative instruments to hedge its investments (including anticipatory hedges) or to seek to enhance </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">returns. The Fund may leverage its assets through the use of proceeds received through tender option bond </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">transactions. In a tender option bond transaction, the Fund transfers municipal bonds or other municipal securities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">into a special purpose entity (a “TOB Trust”). A TOB Trust typically issues two classes of beneficial interests: short-term</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> floating rate interests (“TOB Floaters”), which are sold to third party investors, and residual inverse floating rate </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">interests (“TOB Residuals”), which are generally issued to the Fund. The Fund may invest in TOB Residuals and may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">also invest in TOB Floaters. The Fund will look through to the underlying municipal bond held by a TOB Trust for </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">purposes of the Fund’s 80% policy.</span></div> You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Debt Securities Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Debt securities, such as bonds, involve risks, such as credit risk, interest rate risk, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">extension risk, and prepayment risk, each of which are described in further detail below:</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Credit Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Credit risk refers to the possibility that the issuer of a debt security (i.e., the borrower) will not be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">able to make payments of interest and principal when due. Changes in an issuer’s credit rating or the market’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Interest Rate Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The market value of bonds and other fixed-income securities changes in response to interest </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate changes and other factors. Interest rate risk is the risk that prices of bonds and other fixed-income securities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">will increase as interest rates fall and decrease as interest rates rise.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may be subject to a greater risk of rising interest rates during a period of low interest rates. For example, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">if interest rates increase by 1%, assuming a current portfolio duration of ten years, and all other factors being </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">equal, the value of the Fund’s investments would be expected to decrease by 10%. (Duration is a measure of the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">price sensitivity of a debt security or portfolio of debt securities to relative changes in interest rates.) The magnitude </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of these fluctuations in the market price of bonds and other fixed-income securities is generally greater for those </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">securities with longer maturities. Fluctuations in the market price of the Fund’s investments will not affect interest </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">income derived from instruments already owned by the Fund, but will be reflected in the Fund’s net asset value. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund may lose money if short-term or long-term interest rates rise sharply in a manner not anticipated by Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">management.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">To the extent the Fund invests in debt securities that may be prepaid at the option of the obligor (such as mortgage-backed</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> securities), the sensitivity of such securities to changes in interest rates may increase (to the detriment of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund) when interest rates rise. Moreover, because rates on certain floating rate debt securities typically reset </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">only periodically, changes in prevailing interest rates (and particularly sudden and significant changes) can be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">expected to cause some fluctuations in the net asset value of the Fund to the extent that it invests in floating rate </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">debt securities.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">These basic principles of bond prices also apply to U.S. Government securities. A security backed by the “full faith </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and credit” of the U.S. Government is guaranteed only as to its stated interest rate and face value at maturity, not </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">its current market price. Just like other fixed-income securities, government-guaranteed securities will fluctuate in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">value when interest rates change.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">A general rise in interest rates has the potential to cause investors to move out of fixed-income securities on a large </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">scale, which may increase redemptions from funds that hold large amounts of fixed-income securities. Heavy </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">redemptions could cause the Fund to sell assets at inopportune times or at a loss or depressed value and could </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">hurt the Fund’s performance.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Extension Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — When interest rates rise, certain obligations will be paid off by the obligor more slowly than </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">anticipated, causing the value of these obligations to fall.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Prepayment Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — When interest rates fall, certain obligations will be paid off by the obligor more quickly than </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">originally anticipated, and the Fund may have to invest the proceeds in securities with lower yields.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Municipal Securities Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Municipal securities risks include the ability of the issuer to repay the obligation, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">relative lack of information about certain issuers of municipal securities, and the possibility of future legislative </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">changes which could affect the market for and value of municipal securities. Budgetary constraints of local, state, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and federal governments upon which the issuers may be relying for funding may also impact municipal securities. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">These risks include:</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">General Obligation Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Timely payments depend on the issuer’s credit quality, ability to raise tax </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">revenues and ability to maintain an adequate tax base.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Revenue Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> These payments depend on the money earned by the particular facility or class of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">facilities, or the amount of revenues derived from another source.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Private Activity Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Municipalities and other public authorities issue private activity bonds to finance </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">development of industrial facilities for use by a private enterprise. The private enterprise pays the principal and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">interest on the bond, and the issuer does not pledge its full faith, credit and taxing power for repayment.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Moral Obligation Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Moral obligation bonds are generally issued by special purpose public authorities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of a state or municipality. If the issuer is unable to meet its obligations, repayment of these bonds becomes a moral </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">commitment, but not a legal obligation, of the state or municipality.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Municipal Notes Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Municipal notes are shorter term municipal debt obligations. If there is a shortfall in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">anticipated proceeds, the notes may not be fully repaid and the Fund may lose money.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Municipal Lease Obligations Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> In a municipal lease obligation, the issuer agrees to make payments when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">due on the lease obligation. Although the issuer does not pledge its unlimited taxing power for payment of the lease </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">obligation, the lease obligation is secured by the leased property.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Tax-Exempt Status Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The Fund and its investment manager will rely on the opinion of issuers’ bond counsel </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and, in the case of derivative securities, sponsors’ counsel, on the tax-exempt status of interest on municipal bonds </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and payments under derivative securities. Neither the Fund nor its investment manager will independently review the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">bases for those tax opinions, which may ultimately be determined to be incorrect and subject the Fund and its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shareholders to substantial tax liabilities.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">High Yield Bonds Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Although junk bonds generally pay higher rates of interest than investment grade bonds, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">junk bonds are high risk investments that are considered speculative and may cause income and principal losses </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the Fund.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.0pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Derivatives Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund’s use of derivatives may increase its costs, reduce the Fund’s returns and/or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">increase volatility. Derivatives involve significant risks, including:</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Leverage Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund’s use of derivatives can magnify the Fund’s gains and losses. Relatively small market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">movements may result in large changes in the value of a derivatives position and can result in losses that greatly </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">exceed the amount originally invested.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Market Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Some derivatives are more sensitive to interest rate changes and market price fluctuations than </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">other securities. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">market movements, which losses are potentially unlimited. Finally, BlackRock may not be able to predict correctly </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the direction of securities prices, interest rates and other economic factors, which could cause the Fund’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">derivatives positions to lose value.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Counterparty Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Derivatives are also subject to counterparty risk, which is the risk that the other party in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">transaction will be unable or unwilling to fulfill its contractual obligation, and the related risks of having concentrated </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">exposure to such a counterparty.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Illiquidity Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">difficult for the Fund to value accurately.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Operational Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The use of derivatives includes the risk of potential operational issues, including documentation </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">issues, settlement issues, systems failures, inadequate controls and human error.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Legal Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The risk of insufficient documentation, insufficient capacity or authority of counterparty, or legality or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">enforceability of a contract.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Volatility and Correlation Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Volatility is defined as the characteristic of a security, an index or a market to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">fluctuate significantly in price within a short time period. A risk of the Fund’s use of derivatives is that the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">fluctuations in their values may not correlate with the overall securities markets.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Valuation Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Valuation for derivatives may not be readily available in the market. Valuation may be more difficult </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">in times of market turmoil since many investors and market makers may be reluctant to purchase complex </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">instruments or quote prices for them.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Hedging Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Hedges are sometimes subject to imperfect matching between the derivative and the underlying </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">security, and there can be no assurance that the Fund’s hedging transactions will be effective. The use of hedging </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may result in certain adverse tax consequences.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Tax Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Certain aspects of the tax treatment of derivative instruments, including swap agreements and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">commodity-linked derivative instruments, are currently unclear and may be affected by changes in legislation, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">regulations or other legally binding authority. Such treatment may be less favorable than that given to a direct </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment in an underlying asset and may adversely affect the timing, character and amount of income the Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">realizes from its investments.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Regulatory Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Derivative contracts are subject to regulation under the Dodd-Frank Wall Street Reform and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Consumer Protection Act (the “Dodd-Frank Act”) in the United States and under comparable regimes in Europe, Asia </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and other non-U.S. jurisdictions. Under the Dodd-Frank Act, with respect to uncleared swaps, swap dealers are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">required to exchange variation margin with the Fund and may be required by applicable regulations to collect and/or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">exchange initial margin with the Fund. Both initial and variation margin may be comprised of cash and/or securities, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">subject to applicable regulatory haircuts. In certain cases, shares of investment companies may not be posted as </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">collateral under applicable regulations. In addition, regulations adopted by global prudential regulators require </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">certain bank-regulated counterparties and certain of their affiliates to include in certain financial contracts, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">including many derivatives contracts, terms that delay or restrict the rights of counterparties, such as the Fund, to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">terminate such contracts, foreclose upon collateral, exercise other default rights or restrict transfers of credit </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">support in the event that the counterparty and/or its affiliates are subject to certain types of resolution or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">insolvency proceedings. The implementation of these requirements with respect to derivatives, as well as </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">regulations under global regulations regarding clearing, mandatory trading and margining of other derivatives, may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">increase the costs and risks to the Fund of trading in these instruments and, as a result, may affect returns to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investors in the Fund. Future regulatory developments may impact the Fund’s ability to invest or remain invested in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">certain derivatives. Legislation or regulation may also change the way in which the Fund itself is regulated. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">BlackRock cannot predict the effects of any new governmental regulation that may be implemented on the ability of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund to use swaps or any other financial derivative product, and there can be no assurance that any new </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">governmental regulation will not adversely affect the Fund’s ability to achieve its investment objective.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Illiquid Investments Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund may not acquire any illiquid investment if, immediately after the acquisition, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund would have invested more than 15% of its net assets in illiquid investments. An illiquid investment is any </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">calendar days or less without the sale or disposition significantly changing the market value of the investment. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Liquid investments may become illiquid after purchase by the Fund, particularly during periods of market turmoil. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">There can be no assurance that a security or instrument that is deemed to be liquid when purchased will continue </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to be liquid for as long as it is held by the Fund, and any security or instrument held by the Fund may be deemed an </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">illiquid investment pursuant to the Fund’s liquidity risk management program. The Fund’s illiquid investments may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">reduce the returns of the Fund because it may be difficult to sell the illiquid investments at an advantageous time </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or price. In addition, if the Fund is limited in its ability to dispose of illiquid investments during periods when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shareholders are redeeming or selling their shares or the Fund’s net assets otherwise shrink, the Fund will need to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">dispose of liquid securities to meet redemption requests and illiquid securities will become a larger portion of the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund’s holdings. An investment may be illiquid due to, among other things, the reduced number and capacity of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">traditional market participants to make a market in fixed-income securities or the lack of an active trading market. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">To the extent that the Fund’s principal investment strategies involve derivatives or securities with substantial market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and/or credit risk, the Fund will tend to have greater exposure to the risks associated with illiquid investments. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Illiquid investments may be harder to value, especially in changing markets, and if the Fund is forced to sell these </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investments to meet redemption requests or for other cash needs, the Fund may suffer a loss. This may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">magnified in a rising interest rate environment or other circumstances where investor redemptions or sales of Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shares may be higher than normal. In addition, when there is illiquidity in the market for certain securities, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund, due to limitations on illiquid investments, may be subject to purchase and sale restrictions.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Leverage Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Some transactions may give rise to a form of economic leverage. These transactions may include, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">among others, derivatives, and may expose the Fund to greater risk and increase its costs. The use of leverage may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to meet the applicable requirements of the Investment Company Act of 1940, as amended (the “Investment </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Company Act”) and the rules thereunder. Increases and decreases in the value of the Fund’s portfolio will be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">magnified when the Fund uses leverage.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.0pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Market Risk and Selection Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Market risk is the risk that one or more markets in which the Fund invests will </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">go down in value, including the possibility that the markets will go down sharply and unpredictably. An investor could </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">lose money over short periods due to fluctuation in the Fund’s net asset value in response to short-term market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">movements and over longer periods during market downturns. Securities or other investments held by the Fund may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">underperform the markets, the relevant indices or benchmarks, or the securities selected by other funds with </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">similar investment objectives and investment strategies, or may otherwise fail to perform as intended. The value of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">a security or other asset may decline due to changes in general market conditions, economic trends or events that </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">are not specifically related to the issuer of the security or other asset, or factors that affect a particular issuer or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">issuers, exchange, country, group of countries, region, market, industry, group of industries, sector or asset class. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The success of the Fund’s activities could be affected by interest rates, availability of credit, inflation rates, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">economic uncertainty, changes in laws, tariffs and trade barriers, supply chain disruptions, economic sanctions, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">currency exchange controls, and local, regional or global events such as war, acts of terrorism, natural and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">environmental disasters, the spread of infectious illness or other public health issues, recessions, or other events. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">This means you may lose money.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Recent policy initiatives undertaken by the U.S. government have the potential to impact international relations, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">trade agreements and the overall regulatory environment in ways that could create uncertainty and instability in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">domestic and global markets, and could adversely affect the investment performance of the Fund. In particular, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">actions taken by the U.S. government in respect of international trade relations could lead to trade wars, increased </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">costs for imported goods, disruptions in supply chains, reduced foreign investment, and instability in regions where </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund invests.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Operational and Technology Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund is directly and indirectly susceptible to operational and technology </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">risks, including those related to human errors, processing errors, communication errors, systems failures, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">cybersecurity incidents, and the use of artificial intelligence and machine learning (“AI”), which may result in losses </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the Fund and its shareholders or may impair the Fund’s operations. While the Fund’s service providers are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">required to have appropriate operational, information security and cybersecurity risk management policies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">procedures, their methods of risk management may differ from those of the Fund. Operational and technology risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the issuers in which the Fund invests could also result in material adverse consequences for such issuers and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may cause the Fund’s investments in such issuers to lose value.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Tender Option Bonds and Related Securities Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund’s participation in tender option bond transactions </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may reduce the Fund’s returns and/or increase volatility. Investments in tender option bond transactions expose the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund to counterparty risk and leverage risk. An investment in a tender option bond transaction typically will involve </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">greater risk than an investment in a municipal fixed rate security, including the risk of loss of principal. Distributions </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">on TOB Residuals will bear an inverse relationship to short-term municipal security interest rates. Distributions on </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">TOB Residuals paid to the Fund will be reduced or, in the extreme, eliminated as short-term municipal interest rates </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rise and will increase when short-term municipal interest rates fall. TOB Residuals generally will underperform the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">market for fixed rate municipal securities in a rising interest rate environment. The Fund may invest in TOB Trusts on </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">either a non-recourse or recourse basis. If the Fund invests in a TOB Trust on a recourse basis, it could suffer </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">losses in excess of the value of its TOB Residuals.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Variable Rate Demand Obligations Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Variable rate demand obligations are floating rate securities that </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">combine an interest in a long-term municipal bond with a right to demand payment before maturity from a bank or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">other financial institution. If the bank or financial institution is unable to pay, the Fund may lose money.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> Performance Information <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The information shows you how the Fund’s performance has varied year by year and provides some indication of the</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> risks of investing in the Fund. The table compares the Fund’s performance to that of the Bloomberg Municipal Bond </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Index. To the extent that dividends and distributions have been paid by the Fund, the performance information for the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund in the chart and table assumes reinvestment of the dividends and distributions. As with all such investments,</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> past performance (before and after taxes) is not an indication of future results. The table includes all applicable fees. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">If the Fund’s investment manager and its affiliates had not waived or reimbursed certain Fund expenses during these </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">periods, the Fund’s returns would have been lower. Updated information on the Fund’s performance, including its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">current net asset value, can be obtained by visiting www.blackrock.com or can be obtained by phone at </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">(800) 882-0052</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">.</span></div> The information shows you how the Fund’s performance has varied year by year and provides some indication of the risks of investing in the Fund. As with all such investments, past performance (before and after taxes) is not an indication of future results. www.blackrock.com (800) 882-0052 Service Shares ANNUAL TOTAL RETURNS BlackRock National Municipal Fund As of 12/31 <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">During the ten-year period shown in the bar chart, the highest return for a quarter was 5.87% (quarter ended </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">December 31, 2023) and the lowest return for a quarter was -6.28% (quarter ended March 31, 2022). The year-to-date return as of September 30, 2026 was -3.35%.</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> highest return 0.0587 2023-12-31 lowest return -0.0628 2022-03-31 year-to-date return 2026-09-30 -0.0335 For the periods ended 12/31/25Average Annual Total Returns 0.0299 0.0027 0.0178 0.0299 0.0024 0.0176 0.0323 0.0081 0.0198 0.0425 0.0080 0.0234 <div style="margin-top: 12pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. Fund Overview Key Facts About BlackRock Short Duration Muni Fund Investment Objective <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The investment objective of BlackRock Short Duration Muni Fund (formerly, BlackRock Short-Term Municipal Fund) (the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">“Short Duration Fund” or the “Fund”) is to provide shareholders with as high a level of income exempt from Federal </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">income taxes as is consistent with the investment policies of the Fund.</span></div> Fees and Expenses of the Fund <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">This table describes the fees and expenses that you may pay if you buy, hold and sell Investor A1 Shares of the Fund. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Amounts in the table are rounded to the nearest basis point, which in some cases may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">“</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">0.00.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">”</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> Shareholder Fees (fees paid directly from your investment) 0 0 Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment) 0.0029 0.0010 0.0014 0.0001 0.0054 -0.0007 0.0047 A contingent deferred sales charge (“CDSC”) of 0.50% is assessed on certain redemptions of Investor A1 Shares made within 18 months afterpurchase where no initial sales charge was paid at the time of purchase. The CDSC does not apply to redemptions by certain employer-sponsored retirement plans or to redemptions of shares acquired through reinvestment of dividends and capital gains by existing shareholders. June 30, 2028 Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent AnnualFinancial Statements and Additional Information, which does not include Acquired Fund Fees and Expenses. Example: <div style="line-height: 10.695pt; margin-top: 0.0pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or lower, based on these assumptions your costs would be:</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> 48 166 295 670 Portfolio Turnover: <div style="line-height: 10.695pt; margin-top: 0.0pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">44</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">% of the average value of its portfolio.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> 0.44 Principal Investment Strategies of the Fund <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Under normal circumstances, the Short Duration Fund seeks to achieve its objective by investing at least 80% of its</span> <span style="color: #000000; font-family: arial; font-size: 9.30pt;">net assets, plus the amount of any borrowing for investment purposes, in municipal bonds and derivatives that provide</span> <span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment exposure to such securities or to one or more market risk factors associated with such securities. This </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policy is a fundamental policy of the Fund and may not be changed without approval of a majority of the Fund’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">outstanding securities, as defined in the Investment Company Act. Municipal bonds include debt obligations issued by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or on behalf of a governmental entity or other qualifying issuer that pay interest that is, in the opinion of bond counsel </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to the issuer, generally excludable from gross income for Federal income tax purposes (except that the interest may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">includable in taxable income for purposes of the Federal alternative minimum tax). Municipal bonds may be obligations </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of a variety of issuers, including governmental entities or other qualifying issuers. Issuers may be states, territories </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and possessions of the United States and the District of Columbia and their political subdivisions, agencies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">instrumentalities. Municipal bonds also include short-term tax-exempt obligations like municipal notes and variable </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate demand obligations.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Under normal circumstances, the Short Duration Fund seeks to achieve its objective by investing at least 80% of its</span> <span style="color: #000000; font-family: arial; font-size: 9.30pt;">net assets, plus the amount of any borrowing for investment purposes, in municipal bonds and derivatives that provide</span> <span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment exposure to such securities or to one or more market risk factors associated with such securities. This </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">policy is a fundamental policy of the Fund and may not be changed without approval of a majority of the Fund’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">outstanding securities, as defined in the Investment Company Act. Municipal bonds include debt obligations issued by </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or on behalf of a governmental entity or other qualifying issuer that pay interest that is, in the opinion of bond counsel </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to the issuer, generally excludable from gross income for Federal income tax purposes (except that the interest may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">includable in taxable income for purposes of the Federal alternative minimum tax). Municipal bonds may be obligations </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of a variety of issuers, including governmental entities or other qualifying issuers. Issuers may be states, territories </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and possessions of the United States and the District of Columbia and their political subdivisions, agencies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">instrumentalities. Municipal bonds also include short-term tax-exempt obligations like municipal notes and variable </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate demand obligations.</span></div> <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Short Duration Fund invests primarily in investment grade municipal bonds or municipal notes, including variable </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate demand obligations. Investment grade bonds are securities which are rated in the four highest categories by at </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">least one of the major rating agencies or determined by the management team to be of similar quality. Generally, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">higher the rating of a bond, the higher the likelihood that interest and principal payments will be made on time. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Municipal notes are shorter-term municipal debt obligations that pay interest that is, in the opinion of bond counsel to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the issuer, generally excludable from gross income for Federal income tax purposes (except that the interest may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">includable in taxable income for purposes of the Federal alternative minimum tax) and that have a maturity that is </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">generally one year or less.</span></div> <div style="margin-top: 7pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Under normal circumstances, the effective duration of the Fund’s portfolio is expected to be 4 years or less, as </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">calculated by the Fund’s management team. Effective duration is a measure of the Fund’s price sensitivity to changes </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">in yields or interest rates; however, investors should be aware that effective duration is not an exact measurement and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may not reliably predict a particular security’s price sensitivity to changes in yield or interest rates.</span></div> Under normal circumstances, the Short Duration Fund seeks to achieve its objective by investing at least 80% of itsnet assets, plus the amount of any borrowing for investment purposes, in municipal bonds and derivatives that provideinvestment exposure to such securities or to one or more market risk factors associated with such securities. <div style="margin-top: 7pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Under normal circumstances, the effective duration of the Fund’s portfolio is expected to be 4 years or less, as </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">calculated by the Fund’s management team. Effective duration is a measure of the Fund’s price sensitivity to changes </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">in yields or interest rates; however, investors should be aware that effective duration is not an exact measurement and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may not reliably predict a particular security’s price sensitivity to changes in yield or interest rates.</span></div> You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Debt Securities Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Debt securities, such as bonds, involve risks, such as credit risk, interest rate risk, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">extension risk, and prepayment risk, each of which are described in further detail below:</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Credit Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Credit risk refers to the possibility that the issuer of a debt security (i.e., the borrower) will not be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">able to make payments of interest and principal when due. Changes in an issuer’s credit rating or the market’s </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">degree of credit risk depends on both the financial condition of the issuer and the terms of the obligation.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Interest Rate Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The market value of bonds and other fixed-income securities changes in response to interest </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">rate changes and other factors. Interest rate risk is the risk that prices of bonds and other fixed-income securities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">will increase as interest rates fall and decrease as interest rates rise.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The Fund may be subject to a greater risk of rising interest rates during a period of low interest rates. For example, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">if interest rates increase by 1%, assuming a current portfolio duration of ten years, and all other factors being </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">equal, the value of the Fund’s investments would be expected to decrease by 10%. (Duration is a measure of the </span></div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">price sensitivity of a debt security or portfolio of debt securities to relative changes in interest rates.) The magnitude </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of these fluctuations in the market price of bonds and other fixed-income securities is generally greater for those </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">securities with longer maturities. Fluctuations in the market price of the Fund’s investments will not affect interest </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">income derived from instruments already owned by the Fund, but will be reflected in the Fund’s net asset value. The </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund may lose money if short-term or long-term interest rates rise sharply in a manner not anticipated by Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">management.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">To the extent the Fund invests in debt securities that may be prepaid at the option of the obligor (such as mortgage-backed</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> securities), the sensitivity of such securities to changes in interest rates may increase (to the detriment of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund) when interest rates rise. Moreover, because rates on certain floating rate debt securities typically reset </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">only periodically, changes in prevailing interest rates (and particularly sudden and significant changes) can be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">expected to cause some fluctuations in the net asset value of the Fund to the extent that it invests in floating rate </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">debt securities.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">These basic principles of bond prices also apply to U.S. Government securities. A security backed by the “full faith </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and credit” of the U.S. Government is guaranteed only as to its stated interest rate and face value at maturity, not </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">its current market price. Just like other fixed-income securities, government-guaranteed securities will fluctuate in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">value when interest rates change.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">A general rise in interest rates has the potential to cause investors to move out of fixed-income securities on a large </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">scale, which may increase redemptions from funds that hold large amounts of fixed-income securities. Heavy </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">redemptions could cause the Fund to sell assets at inopportune times or at a loss or depressed value and could </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">hurt the Fund’s performance.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Extension Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — When interest rates rise, certain obligations will be paid off by the obligor more slowly than </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">anticipated, causing the value of these obligations to fall.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Prepayment Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — When interest rates fall, certain obligations will be paid off by the obligor more quickly than </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">originally anticipated, and the Fund may have to invest the proceeds in securities with lower yields.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Municipal Securities Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Municipal securities risks include the ability of the issuer to repay the obligation, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">relative lack of information about certain issuers of municipal securities, and the possibility of future legislative </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">changes which could affect the market for and value of municipal securities. Budgetary constraints of local, state, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and federal governments upon which the issuers may be relying for funding may also impact municipal securities. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">These risks include:</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">General Obligation Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Timely payments depend on the issuer’s credit quality, ability to raise tax </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">revenues and ability to maintain an adequate tax base.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Revenue Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> These payments depend on the money earned by the particular facility or class of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">facilities, or the amount of revenues derived from another source.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Private Activity Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Municipalities and other public authorities issue private activity bonds to finance </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">development of industrial facilities for use by a private enterprise. The private enterprise pays the principal and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">interest on the bond, and the issuer does not pledge its full faith, credit and taxing power for repayment.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Moral Obligation Bonds Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Moral obligation bonds are generally issued by special purpose public authorities </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">of a state or municipality. If the issuer is unable to meet its obligations, repayment of these bonds becomes a moral </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">commitment, but not a legal obligation, of the state or municipality.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Municipal Notes Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Municipal notes are shorter term municipal debt obligations. If there is a shortfall in the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">anticipated proceeds, the notes may not be fully repaid and the Fund may lose money.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Municipal Lease Obligations Risks —</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> In a municipal lease obligation, the issuer agrees to make payments when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">due on the lease obligation. Although the issuer does not pledge its unlimited taxing power for payment of the lease </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">obligation, the lease obligation is secured by the leased property.</span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">Tax-Exempt Status Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — The Fund and its investment manager will rely on the opinion of issuers’ bond counsel </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and, in the case of derivative securities, sponsors’ counsel, on the tax-exempt status of interest on municipal bonds </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and payments under derivative securities. Neither the Fund nor its investment manager will independently review the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">bases for those tax opinions, which may ultimately be determined to be incorrect and subject the Fund and its </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shareholders to substantial tax liabilities.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.0pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Market Risk and Selection Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— Market risk is the risk that one or more markets in which the Fund invests will </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">go down in value, including the possibility that the markets will go down sharply and unpredictably. An investor could </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">lose money over short periods due to fluctuation in the Fund’s net asset value in response to short-term market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">movements and over longer periods during market downturns. Securities or other investments held by the Fund may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">underperform the markets, the relevant indices or benchmarks, or the securities selected by other funds with </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">similar investment objectives and investment strategies, or may otherwise fail to perform as intended. The value of </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div style="line-height: 10.695pt; margin-left: 12pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">a security or other asset may decline due to changes in general market conditions, economic trends or events that </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">are not specifically related to the issuer of the security or other asset, or factors that affect a particular issuer or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">issuers, exchange, country, group of countries, region, market, industry, group of industries, sector or asset class. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The success of the Fund’s activities could be affected by interest rates, availability of credit, inflation rates, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">economic uncertainty, changes in laws, tariffs and trade barriers, supply chain disruptions, economic sanctions, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">currency exchange controls, and local, regional or global events such as war, acts of terrorism, natural and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">environmental disasters, the spread of infectious illness or other public health issues, recessions, or other events.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> <div style="margin-top: 4pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Recent policy initiatives undertaken by the U.S. government have the potential to impact international relations, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">trade agreements and the overall regulatory environment in ways that could create uncertainty and instability in </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">domestic and global markets, and could adversely affect the investment performance of the Fund. In particular, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">actions taken by the U.S. government in respect of international trade relations could lead to trade wars, increased </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">costs for imported goods, disruptions in supply chains, reduced foreign investment, and instability in regions where </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund invests.</span></div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Illiquid Investments Risk </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund may not acquire any illiquid investment if, immediately after the acquisition, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund would have invested more than 15% of its net assets in illiquid investments. An illiquid investment is any </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">calendar days or less without the sale or disposition significantly changing the market value of the investment. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Liquid investments may become illiquid after purchase by the Fund, particularly during periods of market turmoil. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">There can be no assurance that a security or instrument that is deemed to be liquid when purchased will continue </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to be liquid for as long as it is held by the Fund, and any security or instrument held by the Fund may be deemed an </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">illiquid investment pursuant to the Fund’s liquidity risk management program. The Fund’s illiquid investments may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">reduce the returns of the Fund because it may be difficult to sell the illiquid investments at an advantageous time </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">or price. In addition, if the Fund is limited in its ability to dispose of illiquid investments during periods when </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shareholders are redeeming or selling their shares or the Fund’s net assets otherwise shrink, the Fund will need to </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">dispose of liquid securities to meet redemption requests and illiquid securities will become a larger portion of the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund’s holdings. An investment may be illiquid due to, among other things, the reduced number and capacity of </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">traditional market participants to make a market in fixed-income securities or the lack of an active trading market. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">To the extent that the Fund’s principal investment strategies involve derivatives or securities with substantial market </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">and/or credit risk, the Fund will tend to have greater exposure to the risks associated with illiquid investments. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Illiquid investments may be harder to value, especially in changing markets, and if the Fund is forced to sell these </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">investments to meet redemption requests or for other cash needs, the Fund may suffer a loss. This may be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">magnified in a rising interest rate environment or other circumstances where investor redemptions or sales of Fund </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">shares may be higher than normal. In addition, when there is illiquidity in the market for certain securities, the </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Fund, due to limitations on illiquid investments, may be subject to purchase and sale restrictions.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Leverage Risk</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> — Some transactions may give rise to a form of economic leverage. These transactions may include, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">among others, derivatives, and may expose the Fund to greater risk and increase its costs. The use of leverage may </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">to meet the applicable requirements of the Investment Company Act of 1940, as amended (the “Investment </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Company Act”), and the rules thereunder. Increases and decreases in the value of the Fund’s portfolio will be </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">magnified when the Fund uses leverage.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Operational and Technology Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">— The Fund is directly and indirectly susceptible to operational and technology </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">risks, including those related to human errors, processing errors, communication errors, systems failures, </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">cybersecurity incidents, and the use of artificial intelligence and machine learning (“AI”), which may result in losses </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the Fund and its shareholders or may impair the Fund’s operations. While the Fund’s service providers are </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">required to have appropriate operational, information security and cybersecurity risk management policies and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">procedures, their methods of risk management may differ from those of the Fund. Operational and technology risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">for the issuers in which the Fund invests could also result in material adverse consequences for such issuers and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">may cause the Fund’s investments in such issuers to lose value.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> <div> <div style="clear: both; margin-top: 4.805pt; position: relative; width: 100%;"> <div style="float: left; line-height: 9.87pt; text-align: left; width: 8pt;"><span style="color: #000000; font-family: arial; font-size: 8.37pt; position: relative; top: -0.5pt;">◼</span></div> <div style="float: left; line-height: 10.80pt; margin-left: 4pt; text-align: left; width: 505.00pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic; font-weight: bold;">Variable Rate Demand Obligations Risks </span><span style="color: #000000; font-family: arial; font-size: 9.30pt; font-style: italic;">—</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> Variable rate demand obligations are floating rate securities that </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">combine an interest in a long term municipal bond with a right to demand payment before maturity from a bank or </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">other financial institution. If the bank or financial institution is unable to pay, the Fund may lose money.</span></div> </div> <div style="clear: both; position: relative;"> </div> </div> Performance Information <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">The information shows you how the Fund’s performance has varied year by year and provides some indication of the</span> <span style="color: #000000; font-family: arial; font-size: 9.30pt;">risks of investing in the Fund. The table compares the Fund’s performance to that of the Bloomberg Municipal Bond </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Index and the Bloomberg Municipal 1-5 Year Index. To the extent that dividends and distributions have been paid by </span></div> <div style="line-height: 10.695pt; text-align: left;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">the Fund, the performance information for the Fund in the chart and table assumes reinvestment of the dividends and </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">distributions. As with all such investments, past performance (before and after taxes) is not an indication of future</span> <span style="color: #000000; font-family: arial; font-size: 9.30pt;">results. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">However, the table includes all applicable fees and sales charges. If the Fund’s investment manager and its affiliates </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">had not waived or reimbursed certain Fund expenses during these periods, the Fund’s returns would have been lower. </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">Updated information on the Fund’s performance, including its current net asset value, can be obtained by visiting </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">www.blackrock.com or can be obtained by phone at </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">(800) 882-0052</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">.</span></div> The information shows you how the Fund’s performance has varied year by year and provides some indication of therisks of investing in the Fund. As with all such investments, past performance (before and after taxes) is not an indication of futureresults. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. www.blackrock.com (800) 882-0052 Investor A1 Shares ANNUAL TOTAL RETURNS BlackRock Short Duration Muni Fund As of 12/31 <div style="margin-top: 6pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">During the ten-year period shown in the bar chart, the highest return for a quarter was 3.21% (quarter ended </span><span style="color: #000000; font-family: arial; font-size: 9.30pt;">December 31, 2023) and the lowest return for a quarter was -2.64% (quarter ended March 31, 2022). The year-to-date return</span><span style="color: #000000; font-family: arial; font-size: 9.30pt;"> as of September 30, 2026 was -1.37%.</span><span style="color: #000000; font-family: arial; font-size: 1pt; line-height: 0.93pt;"> </span></div> highest return 0.0321 2023-12-31 lowest return -0.0264 2022-03-31 year-to-date return 2026-09-30 -0.0137 For the periods ended 12/31/25Average Annual Total Returns 0.0504 0.0185 0.0148 0.0504 0.0185 0.0148 0.0440 0.0193 0.0151 0.0425 0.0080 0.0234 0.0411 0.0136 0.0167 <div style="margin-top: 12pt;"><span style="color: #000000; font-family: arial; font-size: 9.30pt;">After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not</span> <span style="color: #000000; font-family: arial; font-size: 9.30pt;">reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may</span> <span style="color: #000000; font-family: arial; font-size: 9.30pt;">differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through</span> <span style="color: #000000; font-family: arial; font-size: 9.30pt;">tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.</span><span style="color: #000000; font-family: arial; font-size: 9.30pt; line-height: 10.695pt;"> </span></div> After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do notreflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and maydiffer from those shown, and the after-tax returns shown are not relevant to investors who hold their shares throughtax-deferred arrangements, such as 401(k) plans or individual retirement accounts. As described in the “Management of the Funds” section of the Fund’s prospectus beginning on page 51, BlackRock has contractually agreed to waive the management fee with respect to any portion of the Fund’s assets estimated to be attributable to investments in other equity and fixed-income mutual funds and exchange-traded funds (“ETFs”) managed by BlackRock or its affiliates that have a contractual management fee, through June 30, 2028. In addition, BlackRock has contractually agreed to waive its management fees by the amount of investment advisory fees the Fund pays to BlackRock indirectly through its investment in money market funds managed by BlackRock or its affiliates, through June 30, 2028. The contractual agreements may be terminated upon 90 days’ notice by a majority of the non-interested directors of BlackRock Municipal Bond Fund, Inc. (the “Corporation”) or by a vote of a majority of the outstanding voting securities of the Fund. As described in the “Management of the Funds” section of the Fund’s prospectus beginning on page 51, BlackRock has contractually agreed to waive the management fee with respect to any portion of the Fund’s assets estimated to be attributable to investments in other equity and fixed-income mutual funds and exchange-traded funds (“ETFs”) managed by BlackRock or its affiliates that have a contractual management fee, through June 30, 2028. In addition, BlackRock has contractually agreed to waive its management fees by the amount of investment advisory fees the Fund pays to BlackRock indirectly through its investment in money market funds managed by BlackRock or its affiliates, through June 30, 2028. The contractual agreements may be terminated upon 90 days’ notice by a majority of the non-interested directors of BlackRock Municipal Bond Fund, Inc. (the “Corporation”) or by a vote of a majority of the outstanding voting securities of the Fund. As described in the “Management of the Funds” section of the Fund’s prospectus beginning on page 51, BlackRock has contractually agreed to waive and/or reimburse fees or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and certain other Fund expenses) to 0.61% (for Investor A Shares), 1.36% (for Investor C Shares) and 0.36% (for Institutional Shares) of average daily net assets through June 30, 2028. The contractual agreement may be terminated upon 90 days’ notice by a majority of the non-interested directors of the Corporation or by a vote of a majority of the outstanding voting securities of the Fund. As described in the “Management of the Funds” section of the Fund’s prospectus beginning on page 38, BlackRock has contractually agreed to waive the management fee with respect to any portion of the Fund’s assets estimated to be attributable to investments in other equity and fixed-income mutual funds and exchange-traded funds (“ETFs”) managed by BlackRock or its affiliates that have a contractual management fee, through June 30, 2028. In addition, BlackRock has contractually agreed to waive its management fees by the amount of investment advisory fees the Fund pays to BlackRock indirectly through its investment in money market funds managed by BlackRock or its affiliates, through June 30, 2028. The contractual agreements may be terminated upon 90 days’ notice by a majority of the non-interested directors of BlackRock Municipal Bond Fund, Inc. (the “Corporation”) or by a vote of a majority of the outstanding voting securities of the Fund. The Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent Annual Financial Statements and Additional Information, which do not include Acquired Fund Fees and Expenses. As described in the “Management of the Funds” section of the Fund’s prospectus beginning on page 38, BlackRock has contractually agreed to waive and/or reimburse fees or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and certain other Fund expenses) to 0.38% of average daily net assets through June 30, 2028. The contractual agreement may be terminated upon 90 days’ notice by a majority of the non-interested directors of the Corporation or by a vote of a majority of the outstanding voting securities of the Fund. As described in the “Management of the Funds” section of the Fund’s prospectus beginning on page 38, BlackRock has contractually agreed to waive the management fee with respect to any portion of the Fund’s assets estimated to be attributable to investments in other equity and fixed-income mutual funds and exchange-traded funds (“ETFs”) managed by BlackRock or its affiliates that have a contractual management fee, through June 30, 2028. In addition, BlackRock has contractually agreed to waive its management fees by the amount of investment advisory fees the Fund pays to BlackRock indirectly through its investment in money market funds managed by BlackRock or its affiliates, through June 30, 2028. The contractual agreements may be terminated upon 90 days’ notice by a majority of the non-interested directors of BlackRock Municipal Bond Fund, Inc. (the “Corporation”) or by a vote of a majority of the outstanding voting securities of the Fund. Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent Annual Financial Statements and Additional Information, which does not include Acquired Fund Fees and Expenses. As described in the “Management of the Funds” section of the Fund’s prospectus beginning on page 38, BlackRock has contractually agreed to waive and/or reimburse fees or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and certain other Fund expenses) to 0.31% of average daily net assets through June 30, 2028. The contractual agreement may be terminated upon 90 days’ notice by a majority of the non-interested directors of the Corporation or by a vote of a majority of the outstanding voting securities of the Fund. As described in the “Management of the Fund” section of the Fund’s prospectus beginning on page 29, BlackRock has contractually agreed to waive the management fee with respect to any portion of the Fund’s assets estimated to be attributable to investments in other equity and fixed-income mutual funds and exchange-traded funds (“ETFs”) managed by BlackRock or its affiliates that have a contractual management fee, through June 30, 2028. In addition, BlackRock has contractually agreed to waive its management fees by the amount of investment advisory fees the Fund pays to BlackRock indirectly through its investment in money market funds managed by BlackRock or its affiliates, through June 30, 2028. The contractual agreements may be terminated upon 90 days’ notice by a majority of the non-interested directors of BlackRock Municipal Bond Fund, Inc. (the “Corporation”) or by a vote of a majority of the outstanding voting securities of the Fund. The Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent Annual Financial Statements and Additional Information, which do not include Acquired Fund Fees and Expenses. As described in the “Management of the Fund” section of the Fund’s prospectus beginning on page 29, BlackRock has contractually agreed to waive and/or reimburse fees or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and certain other Fund expenses) to 0.68% of average daily net assets through June 30, 2028. The contractual agreement may be terminated upon 90 days’ notice by a majority of the non-interested directors of the Corporation or by a vote of a majority of the outstanding voting securities of the Fund. As described in the “Management of the Fund” section of the Fund’s prospectus beginning on page 28, BlackRock Advisors, LLC (“BlackRock”) has contractually agreed to waive the management fee with respect to any portion of the Fund’s assets estimated to be attributable to investments in other equity and fixed-income mutual funds and exchange-traded funds (“ETFs”) managed by BlackRock or its affiliates that have a contractual management fee, through June 30, 2028. In addition, BlackRock has contractually agreed to waive its management fees by the amount of investment advisory fees the Fund pays to BlackRock indirectly through its investment in money market funds managed by BlackRock or its affiliates, through June 30, 2028. The contractual agreements may be terminated upon 90 days’ notice by a majority of the non-interested directors of BlackRock Municipal Bond Fund, Inc. (the “Corporation”) or by a vote of a majority of the outstanding voting securities of the Fund. Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent Annual Financial Statements and Additional Information, which does not include Acquired Fund Fees and Expenses. As described in the “Management of the Fund” section of the Fund’s prospectus beginning on page 28, BlackRock has contractually agreed to waive and/or reimburse fees or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and certain other Fund expenses) to 0.46% of average daily net assets through June 30, 2028. The contractual agreement may be terminated upon 90 days’ notice by a majority of the non-interested directors of the Corporation or by a vote of a majority of the outstanding voting securities of the Fund. Investor A1 Shares are subject to a maximum sales charge on purchases of 1.00%. The sales charge does not apply to dividend and capital gain reinvestments by existing shareholders and new purchases for certain employer-sponsored retirement plans, which are currently the only investors who may invest in Investor A1 Shares. A contingent deferred sales charge (“CDSC”) of 0.50% is assessed on certain redemptions of Investor A1 Shares made within 18 months after purchase where no initial sales charge was paid at the time of purchase. The CDSC does not apply to redemptions by certain employer-sponsored retirement plans or to redemptions of shares acquired through reinvestment of dividends and capital gains by existing shareholders. The Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent Annual Financial Statements and Additional Information, which do not include Acquired Fund Fees and Expenses. As described in the “Management of the Funds” section of the Fund’s prospectus beginning on page 51, BlackRock has contractually agreed to waive and/or reimburse fees or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and certain other Fund expenses) to 0.68% (for Investor A Shares), 1.43% (for Investor C Shares) and 0.43% (for Institutional Shares) of average daily net assets through June 30, 2028. The contractual agreement may be terminated upon 90 days’ notice by a majority of the non-interested directors of the Corporation or by a vote of a majority of the outstanding voting securities of the Fund. A contingent deferred sales charge (“CDSC”) of 1.00% is assessed on certain redemptions of Investor A Shares made within 18 months after purchase where no initial sales charge was paid at the time of purchase as part of an investment of $250,000 or more. There is no CDSC on Investor C Shares after one year. A contingent deferred sales charge (“CDSC”) of 0.25% is assessed on certain redemptions of Investor A Shares made within 9 months after purchase where no initial sales charge was paid at the time of purchase as part of an investment of $250,000 or more. There is no CDSC on Investor C Shares after one year. Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent Annual Financial Statements and Additional Information, which does not include Acquired Fund Fees and Expenses.