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  <xsd:element abstract="true" id="hrzn_CommonStockWarrantsMember" name="CommonStockWarrantsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_CommunicationsSectorMember" name="CommunicationsSectorMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_ConsumerrelatedSectorMember" name="ConsumerrelatedSectorMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_ConsumerrelatedTechnologiesMember" name="ConsumerrelatedTechnologiesMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_ConventusOrthopaedicsIncMember" name="ConventusOrthopaedicsIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_ConversionOf2030NotesIntoCommonStockMember" name="ConversionOf2030NotesIntoCommonStockMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_ConversionOf2031NotesIntoCommonStockMember" name="ConversionOf2031NotesIntoCommonStockMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_CraftyHoldingsIncMember" name="CraftyHoldingsIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_CreditFacilitiesMember" name="CreditFacilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_DataStorageSectorMember" name="DataStorageSectorMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_DebtInstrumentAssetCoveragePerUnit" name="DebtInstrumentAssetCoveragePerUnit" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_DebtInstrumentAverageMarketValuePerShare" name="DebtInstrumentAverageMarketValuePerShare" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_DebtInstrumentBasisSpreadOnVariableRateTreasuryYieldMaturity" name="DebtInstrumentBasisSpreadOnVariableRateTreasuryYieldMaturity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_DebtInstrumentConvertibleAcceleratedUnamortizedDebtIssuanceCosts" name="DebtInstrumentConvertibleAcceleratedUnamortizedDebtIssuanceCosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_DebtInstrumentConvertibleMaximumBeneficialOwnershipPercentage" name="DebtInstrumentConvertibleMaximumBeneficialOwnershipPercentage" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_DebtInstrumentConvertibleWeightedAverageConversionPrice" name="DebtInstrumentConvertibleWeightedAverageConversionPrice" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_DebtInstrumentInterestRateIncreaseFromDefault" name="DebtInstrumentInterestRateIncreaseFromDefault" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_DebtInstrumentInterestRateIncreaseFromFailureToMaintainInvestmentRating" name="DebtInstrumentInterestRateIncreaseFromFailureToMaintainInvestmentRating" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_DebtInstrumentSharePrice" name="DebtInstrumentSharePrice" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_DebtInstrumentVariableRate" name="DebtInstrumentVariableRate" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="hrzn_DebtInvestmentsMember" name="DebtInvestmentsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_December312025ExpirationMember" name="December312025ExpirationMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_December312026ExpirationMember" name="December312026ExpirationMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_December312027ExpirationMember" name="December312027ExpirationMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_DecisyonIncMember" name="DecisyonIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_DiagnosticsSectorMember" name="DiagnosticsSectorMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_DistributionsPolicyTextBlock" name="DistributionsPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_DivergentTechnologiesIncMember" name="DivergentTechnologiesIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_DocumentAndEntityInformation" name="DocumentAndEntityInformation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_DropOffIncMember" name="DropOffIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_ELaCarteIncMember" name="ELaCarteIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_ElligoHealthResearchIncMember" name="ElligoHealthResearchIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_ElligoHealthcareResearchIncMember" name="ElligoHealthcareResearchIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_EmalexBiosciencesIncMember" name="EmalexBiosciencesIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_EndoftermPaymentsReceivableNoncashTransaction" name="EndoftermPaymentsReceivableNoncashTransaction" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_EnergyEfficiencyMember" name="EnergyEfficiencyMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_EquityPurchaseAgreementMember" name="EquityPurchaseAgreementMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_EquityReceivedInSettlementOfInterestAndFeeIncome" name="EquityReceivedInSettlementOfInterestAndFeeIncome" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_EquitySalesAgreementMaximumValue" name="EquitySalesAgreementMaximumValue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_EquitySalesAgreementRemainingAmountAvailableForIssuance" name="EquitySalesAgreementRemainingAmountAvailableForIssuance" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="hrzn_EstimatedTimeToExitMember" name="EstimatedTimeToExitMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_EveloBiosciencesIncMember" name="EveloBiosciencesIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_EverstreamHoldingsLLCMember" name="EverstreamHoldingsLLCMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAppreciationDepreciationIncludedInEarnings" name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAppreciationDepreciationIncludedInEarnings" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOtherPeriodIncreaseDecrease" name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOtherPeriodIncreaseDecrease" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPaymentInkindInterest" name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPaymentInkindInterest" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetRealizedGainLossIncludedInEarnings" name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetRealizedGainLossIncludedInEarnings" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersBetweenInvestments" name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersBetweenInvestments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetWarrantsAndEquityReceived" name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetWarrantsAndEquityReceived" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_FederalExciseTaxPercent" name="FederalExciseTaxPercent" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="hrzn_FictivIncMember" name="FictivIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_FourInvestmentsMember" name="FourInvestmentsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_GTMedicalTechnologiesIncMember" name="GTMedicalTechnologiesIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_GetaroundIncMember" name="GetaroundIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_GlobalWorldwideLlcMember" name="GlobalWorldwideLlcMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_GreenlightBiosciencesIncMember" name="GreenlightBiosciencesIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_HIMVLLCMember" name="HIMVLLCMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_HappyCoIncMember" name="HappyCoIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_HavenlyIncMember" name="HavenlyIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_HealthcareInformationAndServicesSegmentMember" name="HealthcareInformationAndServicesSegmentMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_HometeamTechnologiesIncMember" name="HometeamTechnologiesIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_HorizonTechnologyFinanceCorporationMember" name="HorizonTechnologyFinanceCorporationMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_HorizonTechnologyFinanceManagementLLCTheAdvisorMember" name="HorizonTechnologyFinanceManagementLLCTheAdvisorMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_HoundLabsIILLCMember" name="HoundLabsIILLCMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_HoundLabsIncMember" name="HoundLabsIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_HypotheticalMarketYieldMember" name="HypotheticalMarketYieldMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_ImunonIncMember" name="ImunonIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_IncentiveFeeCapAndDeferralMechanismContingentFutureLiability" name="IncentiveFeeCapAndDeferralMechanismContingentFutureLiability" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_IncentiveFeeCapAndDeferralMechanismReductionToExpense" name="IncentiveFeeCapAndDeferralMechanismReductionToExpense" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_IncentiveFeeToPreincentiveNetInvestmentIncome" name="IncentiveFeeToPreincentiveNetInvestmentIncome" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_IncreaseDecreaseInEndoftermPayments" name="IncreaseDecreaseInEndoftermPayments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_IncreaseDecreaseInUnearnedIncome" name="IncreaseDecreaseInUnearnedIncome" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_InfobionicIncMember" name="InfobionicIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_IntelepeerHoldingsIncMember" name="IntelepeerHoldingsIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InterestIncomeNet" name="InterestIncomeNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="hrzn_InternetAndMediaSectorMember" name="InternetAndMediaSectorMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentAssetsMeasurementInput" name="InvestmentAssetsMeasurementInput" nillable="true" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_InvestmentCompanyAverageDebtPerShare" name="InvestmentCompanyAverageDebtPerShare" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentCompanyDistributableEarningsLossAccumulatedAppreciation" name="InvestmentCompanyDistributableEarningsLossAccumulatedAppreciation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_InvestmentCompanyDistributableEarningsLossAccumulatedDepreciation" name="InvestmentCompanyDistributableEarningsLossAccumulatedDepreciation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_InvestmentCompanyDistributableEarningsLossAccumulatedOtherTemporaryDifferences" name="InvestmentCompanyDistributableEarningsLossAccumulatedOtherTemporaryDifferences" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_InvestmentCompanyDistributionToShareholdersPerShareNetInvestmentIncome" name="InvestmentCompanyDistributionToShareholdersPerShareNetInvestmentIncome" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentCompanyDistributionToShareholdersPerShareNetRealizedGainOnInvestments" name="InvestmentCompanyDistributionToShareholdersPerShareNetRealizedGainOnInvestments" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_InvestmentCompanyDistributionToShareholdersPerShareOther" name="InvestmentCompanyDistributionToShareholdersPerShareOther" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentCompanyDividendDistributionPaid" name="InvestmentCompanyDividendDistributionPaid" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentCompanyExpenseRatioExcludingIncentiveFeeAndVoluntaryFeeWaiver" name="InvestmentCompanyExpenseRatioExcludingIncentiveFeeAndVoluntaryFeeWaiver" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentCompanyExpenseRatioExcludingVoluntaryFeeWaiver" name="InvestmentCompanyExpenseRatioExcludingVoluntaryFeeWaiver" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentCompanyIncentiveFeeToAverageNetAssetsExcludingVoluntaryFeeWaiver" name="InvestmentCompanyIncentiveFeeToAverageNetAssetsExcludingVoluntaryFeeWaiver" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentCompanyInvestmentDepreciationAppreciationPerShare" name="InvestmentCompanyInvestmentDepreciationAppreciationPerShare" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentCompanyInvestmentIncomeLossRatioAfterIncentiveAllocationExcludingVoluntaryFeeWaiver" name="InvestmentCompanyInvestmentIncomeLossRatioAfterIncentiveAllocationExcludingVoluntaryFeeWaiver" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentCompanyInvestmentIncomeNet" name="InvestmentCompanyInvestmentIncomeNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentCompanyNetAssetValuePerSharePeriodIncreaseDecreaseDiluted" name="InvestmentCompanyNetAssetValuePerSharePeriodIncreaseDecreaseDiluted" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentCompanyPortfolioTurnoverRatio" name="InvestmentCompanyPortfolioTurnoverRatio" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentCompanyRetainedEarningsAccumulatedDeficit" name="InvestmentCompanyRetainedEarningsAccumulatedDeficit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_InvestmentCompanyTotalDistribution" name="InvestmentCompanyTotalDistribution" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_InvestmentConcentrationRiskMember" name="InvestmentConcentrationRiskMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentIncomeAttributableToNoncashPaidinkindInterestPercent" name="InvestmentIncomeAttributableToNoncashPaidinkindInterestPercent" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentInterestBasisSpreadVariableRate" name="InvestmentInterestBasisSpreadVariableRate" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="hrzn_InvestmentManagementAgreementMember" name="InvestmentManagementAgreementMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentNonaccrualIncomeNotReceivedInCashPercent" name="InvestmentNonaccrualIncomeNotReceivedInCashPercent" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentOwnedCeilingRate" name="InvestmentOwnedCeilingRate" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_InvestmentOwnedEndOfTermPaymentsETP" name="InvestmentOwnedEndOfTermPaymentsETP" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_InvestmentsCostNonaccrualStatus" name="InvestmentsCostNonaccrualStatus" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_InvestmentsFairValueNonaccrualStatus" name="InvestmentsFairValueNonaccrualStatus" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_InvestmentsInAndAdvancesToAffiliatesAtFairValueDiscountAccretion" name="InvestmentsInAndAdvancesToAffiliatesAtFairValueDiscountAccretion" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentsInAndAdvancesToAffiliatesAtFairValueTransfers" name="InvestmentsInAndAdvancesToAffiliatesAtFairValueTransfers" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_InvestmentsNonaccrualInterestIncome" name="InvestmentsNonaccrualInterestIncome" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_June302026ExpirationMember" name="June302026ExpirationMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_June302027ExpirationMember" name="June302027ExpirationMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_June302028ExpirationMember" name="June302028ExpirationMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_KSQTherapeuticsIncMember" name="KSQTherapeuticsIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_KateFarmsIncMember" name="KateFarmsIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_KeyFacilityMember" name="KeyFacilityMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_KodiakRoboticsIncMember" name="KodiakRoboticsIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_LastEquityFinancingMember" name="LastEquityFinancingMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_LemongrassHoldingsIncMember" name="LemongrassHoldingsIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_LiabilitiesAndNetAssets" name="LiabilitiesAndNetAssets" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="hrzn_LifeScienceSegmentMember" name="LifeScienceSegmentMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_LineOfCreditFacilityAdvanceRate" name="LineOfCreditFacilityAdvanceRate" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_LineOfCreditFacilityAdvanceRateOfEligibleDebtInvestments" name="LineOfCreditFacilityAdvanceRateOfEligibleDebtInvestments" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_LineOfCreditFacilityChangeInMaximumBorrowingCapacity" name="LineOfCreditFacilityChangeInMaximumBorrowingCapacity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_LineOfCreditFacilityMaximumBorrowingCapacityAccordianFeature" name="LineOfCreditFacilityMaximumBorrowingCapacityAccordianFeature" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element id="hrzn_LineOfCreditFacilityMaximumBorrowingCapacityAccordionFeature" name="LineOfCreditFacilityMaximumBorrowingCapacityAccordionFeature" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="hrzn_LiqidIncMember" name="LiqidIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_LiquiglideIncMember" name="LiquiglideIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_LongGrovePharmaceuticalLLCMember" name="LongGrovePharmaceuticalLLCMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_LotameSolutionsIncMember" name="LotameSolutionsIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_LumitheraIncMember" name="LumitheraIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_LyricalFoodsIncMember" name="LyricalFoodsIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MMLUSIncMember" name="MMLUSIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MagnoliaMedicalTechnologiesIncMember" name="MagnoliaMedicalTechnologiesIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_March312026ExpirationMember" name="March312026ExpirationMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_March312027ExpirationMember" name="March312027ExpirationMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_March312028ExpirationMember" name="March312028ExpirationMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MasteryprepLlcMember" name="MasteryprepLlcMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MeasurementInputHypotheticalMarketYieldsMember" name="MeasurementInputHypotheticalMarketYieldsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MedicalDeviceSectorMember" name="MedicalDeviceSectorMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MeditrinaIncMember" name="MeditrinaIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MedsphereSystemsCorporationMember" name="MedsphereSystemsCorporationMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MergerAgreementFeeWaiverMember" name="MergerAgreementFeeWaiverMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MicroTransponderIncMember" name="MicroTransponderIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MirantisIncMember" name="MirantisIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MobiaMedicalIncMember" name="MobiaMedicalIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MomentumUSBidcoLLCMember" name="MomentumUSBidcoLLCMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MonroeCapitalIntermediateHoldingsLLCMember" name="MonroeCapitalIntermediateHoldingsLLCMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MultipleProbabilityWeightedCashFlowModelMember" name="MultipleProbabilityWeightedCashFlowModelMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MultipleProbabilityWeightedScenarioModelMember" name="MultipleProbabilityWeightedScenarioModelMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MustangBioIncMember" name="MustangBioIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_MyForestFoodsCoMember" name="MyForestFoodsCoMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_NYLFacilityMember" name="NYLFacilityMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_NativeMicrobialsIncMember" name="NativeMicrobialsIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_NetAssets" name="NetAssets" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="hrzn_NetworkingSectorMember" name="NetworkingSectorMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_NewAerofarmsIncAssigneeOfAerofarmsIncMember" name="NewAerofarmsIncAssigneeOfAerofarmsIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_NexiiBuildingSolutionsIncMember" name="NexiiBuildingSolutionsIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_NextCarHoldingCompanyIncMember" name="NextCarHoldingCompanyIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_NoodlePartnersIncMember" name="NoodlePartnersIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_NoteToFinancialStatementDetailsTextual" name="NoteToFinancialStatementDetailsTextual" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_NotesToFinancialStatements" name="NotesToFinancialStatements" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_NotesToFinancialStatementsAbstract" name="NotesToFinancialStatementsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_NuveenFacilityMember" name="NuveenFacilityMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2024M101DividendsMember" name="O2024M101DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2024M102DividendsMember" name="O2024M102DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2024M103DividendsMember" name="O2024M103DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2024M21DividendsMember" name="O2024M21DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2024M22DividendsMember" name="O2024M22DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2024M23DividendsMember" name="O2024M23DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2024M24DividendsMember" name="O2024M24DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
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  <xsd:element abstract="true" id="hrzn_O2024M71DividendsMember" name="O2024M71DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
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  <xsd:element abstract="true" id="hrzn_O2024M73DividendsMember" name="O2024M73DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2025M101DividendsMember" name="O2025M101DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
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  <xsd:element abstract="true" id="hrzn_O2025M21DividendsMember" name="O2025M21DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2025M22DividendsMember" name="O2025M22DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2025M23DividendsMember" name="O2025M23DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2025M41DividendsMember" name="O2025M41DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2025M42DividendsMember" name="O2025M42DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2025M43DividendsMember" name="O2025M43DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2025M72DividendsMember" name="O2025M72DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2025M73DividendsMember" name="O2025M73DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2025M7DividendsMember" name="O2025M7DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2026M3DividendsMember" name="O2026M3DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2026M4DividendsMember" name="O2026M4DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_O2026M5DividendsMember" name="O2026M5DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_OneInvestmentMember" name="OneInvestmentMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_OneNetworksIncdbaFinexioMember" name="OneNetworksIncdbaFinexioMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_OnkosSurgicalIncMember" name="OnkosSurgicalIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_OptoroIncMember" name="OptoroIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_OtherBooktaxDifferences" name="OtherBooktaxDifferences" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_OtherHealthcareSectorMember" name="OtherHealthcareSectorMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_OtherInvestmentsPrimeIndexFiveMember" name="OtherInvestmentsPrimeIndexFiveMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_OtherInvestmentsPrimeIndexFourMember" name="OtherInvestmentsPrimeIndexFourMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_OtherInvestmentsPrimeIndexOneMember" name="OtherInvestmentsPrimeIndexOneMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_OtherInvestmentsPrimeIndexSixMember" name="OtherInvestmentsPrimeIndexSixMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_OtherInvestmentsPrimeIndexThreeMember" name="OtherInvestmentsPrimeIndexThreeMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_OtherInvestmentsPrimeIndexTwoMember" name="OtherInvestmentsPrimeIndexTwoMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_OtherSustainabilitySectorMember" name="OtherSustainabilitySectorMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_OwnershipPercentageAcquired" name="OwnershipPercentageAcquired" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="hrzn_PDSBiotechnologyCorporationMember" name="PDSBiotechnologyCorporationMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_ParseBiosciencesIncMember" name="ParseBiosciencesIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_PebblepostIncMember" name="PebblepostIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_PelthosTherapeuticsIncMember" name="PelthosTherapeuticsIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_PerformanceBasedIncentiveFee" name="PerformanceBasedIncentiveFee" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_PivotBioIncMember" name="PivotBioIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_PolicyTable" name="PolicyTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_PreferredStock2Member" name="PreferredStock2Member" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_PreferredStockWarrantsMember" name="PreferredStockWarrantsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_PreincentiveFeeNetInvestmentIncomeCatchupPercent" name="PreincentiveFeeNetInvestmentIncomeCatchupPercent" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_PreincentiveFeeNetInvestmentIncomeHurdleRate" name="PreincentiveFeeNetInvestmentIncomeHurdleRate" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_PreincentiveFeeNetInvestmentIncomeHurdleRateAnnualized" name="PreincentiveFeeNetInvestmentIncomeHurdleRateAnnualized" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="hrzn_PreincentiveFeeNetInvestmentIncomeMaximumRateToTriggerCatchup" name="PreincentiveFeeNetInvestmentIncomeMaximumRateToTriggerCatchup" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
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  <xsd:element abstract="true" id="hrzn_PrimaryKidsIncMember" name="PrimaryKidsIncMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
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  <xsd:element abstract="true" id="hrzn_statement-statement-note-4-investments-tables" name="statement-statement-note-4-investments-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-note-5-transactions-with-affiliated-companies-investments-in-controlled-affiliated-companies-details" name="statement-statement-note-5-transactions-with-affiliated-companies-investments-in-controlled-affiliated-companies-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-note-5-transactions-with-affiliated-companies-tables" name="statement-statement-note-5-transactions-with-affiliated-companies-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-note-6-fair-value-assets-at-fair-value-on-a-recurring-basis-details" name="statement-statement-note-6-fair-value-assets-at-fair-value-on-a-recurring-basis-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-note-6-fair-value-reconciliation-of-level-3-assets-measured-on-a-recurring-basis-details" name="statement-statement-note-6-fair-value-reconciliation-of-level-3-assets-measured-on-a-recurring-basis-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-note-6-fair-value-significant-level-3-fair-value-measurement-inputs-details" name="statement-statement-note-6-fair-value-significant-level-3-fair-value-measurement-inputs-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-note-6-fair-value-tables" name="statement-statement-note-6-fair-value-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-note-7-borrowings-borrowings-details" name="statement-statement-note-7-borrowings-borrowings-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-note-7-borrowings-senior-securities-details" name="statement-statement-note-7-borrowings-senior-securities-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-note-7-borrowings-tables" name="statement-statement-note-7-borrowings-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-note-8-federal-income-tax-reconciliation-of-net-increase-in-net-assets-to-taxable-income-details" name="statement-statement-note-8-federal-income-tax-reconciliation-of-net-increase-in-net-assets-to-taxable-income-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-note-8-federal-income-tax-tables" name="statement-statement-note-8-federal-income-tax-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-note-8-federal-income-tax-tax-characters-of-distributions-paid-details" name="statement-statement-note-8-federal-income-tax-tax-characters-of-distributions-paid-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-note-8-federal-income-tax-undistributed-ordinary-income-earnings-on-a-tax-basis-details" name="statement-statement-note-8-federal-income-tax-undistributed-ordinary-income-earnings-on-a-tax-basis-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-note-9-financial-instruments-with-offbalancesheet-risk-tables" name="statement-statement-note-9-financial-instruments-with-offbalancesheet-risk-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-note-9-financial-instruments-with-offbalancesheet-risk-unfunded-commitments-details" name="statement-statement-note-9-financial-instruments-with-offbalancesheet-risk-unfunded-commitments-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="hrzn_statement-statement-significant-accounting-policies-policies" name="statement-statement-significant-accounting-policies-policies" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
</xsd:schema>
