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  <xs:element id="gain_PercentageOfAcquiredNonQualifyingAssetsOfTotalAssets" abstract="false" name="PercentageOfAcquiredNonQualifyingAssetsOfTotalAssets" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_RegistrationStatementAndCommonEquityOfferingsTextBlock" abstract="false" name="RegistrationStatementAndCommonEquityOfferingsTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="gain_UnconsolidatedSignificantSubsidiariesTextBlock" abstract="false" name="UnconsolidatedSignificantSubsidiariesTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="gain_RelatedPartyFeesPolicyTextBlock" abstract="false" name="RelatedPartyFeesPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="gain_InvestmentCompanyCashDistributionsPaidToCommonStockholdersTableTextBlock" abstract="false" name="InvestmentCompanyCashDistributionsPaidToCommonStockholdersTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="gain_ScheduleOfPrincipalBalancesOfUnusedLineOfCreditAndDelayedDrawTermDebtCommitmentsAndGuarantiesTableTextBlock" abstract="false" name="ScheduleOfPrincipalBalancesOfUnusedLineOfCreditAndDelayedDrawTermDebtCommitmentsAndGuarantiesTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="gain_InvestmentPortfolioDebtInvestmentsIntendedPercent" abstract="false" name="InvestmentPortfolioDebtInvestmentsIntendedPercent" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_InvestmentPortfolioEquityInvestmentsIntendedPercent" abstract="false" name="InvestmentPortfolioEquityInvestmentsIntendedPercent" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_InvestmentPortfolioDebtInvestmentsActualPercent" abstract="false" name="InvestmentPortfolioDebtInvestmentsActualPercent" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_InvestmentPortfolioEquityInvestmentsActualPercent" abstract="false" name="InvestmentPortfolioEquityInvestmentsActualPercent" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_BTGroupAcquisitionInc.EdgeAdhesivesHoldingsInc.AndJ.R.HobbsCoMember" abstract="true" name="BTGroupAcquisitionInc.EdgeAdhesivesHoldingsInc.AndJ.R.HobbsCoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_BTDiligentEdgeAndJ.R.HobbsCo.AtlantaLLCJ.R.HobbsMember" abstract="true" name="BTDiligentEdgeAndJ.R.HobbsCo.AtlantaLLCJ.R.HobbsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_InvestmentOwnedPercentOfVotingSecurities" abstract="false" name="InvestmentOwnedPercentOfVotingSecurities" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_InvestmentOwnedPercentOfCostBasis" abstract="false" name="InvestmentOwnedPercentOfCostBasis" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_InvestmentOwnedPercentOfFairValue" abstract="false" name="InvestmentOwnedPercentOfFairValue" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_GladstoneAlternativeIncomeFundGALTMember" abstract="true" name="GladstoneAlternativeIncomeFundGALTMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_TotalEnterpriseValueMember" abstract="true" name="TotalEnterpriseValueMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_YieldAnalysisMember" abstract="true" name="YieldAnalysisMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_MeasurementInputEBITDAMember" abstract="true" name="MeasurementInputEBITDAMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_MeasurementInputRevenueMember" abstract="true" name="MeasurementInputRevenueMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_DebtAndEquitySecuritiesRealizedGainLossMember" abstract="true" name="DebtAndEquitySecuritiesRealizedGainLossMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_DebtAndEquitySecuritiesUnrealizedGainLossMember" abstract="true" name="DebtAndEquitySecuritiesUnrealizedGainLossMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_OldWorldChristmasInc.Member" abstract="true" name="OldWorldChristmasInc.Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_PSIMoldedPlasticsIncMember" abstract="true" name="PSIMoldedPlasticsIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_HorizonFacilitiesServicesIncMember" abstract="true" name="HorizonFacilitiesServicesIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_SFEGHoldingsIncMember" abstract="true" name="SFEGHoldingsIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetReversalOfPreviouslyRecordedAppreciationDepreciationUponRealization" abstract="false" name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetReversalOfPreviouslyRecordedAppreciationDepreciationUponRealization" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_FiveLargestPortfolioInvestmentsMember" abstract="true" name="FiveLargestPortfolioInvestmentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_InvestmentPortfolioBenchmarkMember" abstract="true" name="InvestmentPortfolioBenchmarkMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_NumberOfInvestmentPortfolioCompany" abstract="false" name="NumberOfInvestmentPortfolioCompany" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="gain_NumberOfStatesWherePortfolioCompanyInvestmentsAreLocated" abstract="false" name="NumberOfStatesWherePortfolioCompanyInvestmentsAreLocated" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="gain_NumberOfIndustriesInvestedIn" abstract="false" name="NumberOfIndustriesInvestedIn" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="gain_UncollectibleReceivablesAllowanceMinimumRequiredDayForUncollectibleAdjustment" abstract="false" name="UncollectibleReceivablesAllowanceMinimumRequiredDayForUncollectibleAdjustment" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="gain_InvestmentCompanyGrossReceivablesFromPortfolioCompanies" abstract="false" name="InvestmentCompanyGrossReceivablesFromPortfolioCompanies" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_InvestmentCompanyAllowanceForUncollectibleReceivables" abstract="false" name="InvestmentCompanyAllowanceForUncollectibleReceivables" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_OtherSectorsMember" abstract="true" name="OtherSectorsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_InvestmentOwnedAtCostMember" abstract="true" name="InvestmentOwnedAtCostMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_InvestmentOwnedAtFairValueMember" abstract="true" name="InvestmentOwnedAtFairValueMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_InvestmentTypeConcentrationRiskMember" abstract="true" name="InvestmentTypeConcentrationRiskMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_IndustryConcentrationRiskMember" abstract="true" name="IndustryConcentrationRiskMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_GeographicRegionsConcentrationRiskMember" abstract="true" name="GeographicRegionsConcentrationRiskMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_PrincipalRepaymentAndMaturityOfInvestmentsYearOne" abstract="false" name="PrincipalRepaymentAndMaturityOfInvestmentsYearOne" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_PrincipalRepaymentAndMaturityOfInvestmentsYearTwo" abstract="false" name="PrincipalRepaymentAndMaturityOfInvestmentsYearTwo" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_PrincipalRepaymentAndMaturityOfInvestmentsYearThree" abstract="false" name="PrincipalRepaymentAndMaturityOfInvestmentsYearThree" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_PrincipalRepaymentAndMaturityOfInvestmentsYearFour" abstract="false" name="PrincipalRepaymentAndMaturityOfInvestmentsYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_PrincipalRepaymentAndMaturityOfInvestmentsYearFive" abstract="false" name="PrincipalRepaymentAndMaturityOfInvestmentsYearFive" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_PrincipalRepaymentAndMaturityOfInvestmentsAfterYearFive" abstract="false" name="PrincipalRepaymentAndMaturityOfInvestmentsAfterYearFive" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_PrincipalRepaymentAndMaturityOfInvestments" abstract="false" name="PrincipalRepaymentAndMaturityOfInvestments" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_GladstoneSecuritiesLLCMember" abstract="true" name="GladstoneSecuritiesLLCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_AdvisoryAgreementMember" abstract="true" name="AdvisoryAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_ManagementAndServiceFeesPercentOfFeeCreditsAgainstBaseManagementFee" abstract="false" name="ManagementAndServiceFeesPercentOfFeeCreditsAgainstBaseManagementFee" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_ManagementAndServiceFeesMaximumAsAPercentageOfTotalAssets" abstract="false" name="ManagementAndServiceFeesMaximumAsAPercentageOfTotalAssets" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_InvestmentCompanyIncentiveFeeWhenPreInventiveFeeNetInvestmentIncomeDoesNotExceedHurdleRate" abstract="false" name="InvestmentCompanyIncentiveFeeWhenPreInventiveFeeNetInvestmentIncomeDoesNotExceedHurdleRate" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_InvestmentCompanyPercentageOfPreIncentiveFeeNetInvestmentIncomeExceedsTheHurdleRate" abstract="false" name="InvestmentCompanyPercentageOfPreIncentiveFeeNetInvestmentIncomeExceedsTheHurdleRate" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_InvestmentCompanyPreIncentiveFeeNetInvestmentIncomePercentThresholdOfNetAssets" abstract="false" name="InvestmentCompanyPreIncentiveFeeNetInvestmentIncomePercentThresholdOfNetAssets" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_InvestmentCompanyPercentOfPreIncentiveFeeNetInvestmentIncomeThatExceedsNetAssetsThreshold" abstract="false" name="InvestmentCompanyPercentOfPreIncentiveFeeNetInvestmentIncomeThatExceedsNetAssetsThreshold" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_InvestmentCompanyCapitalGainsBasedIncentiveFeesPercentage" abstract="false" name="InvestmentCompanyCapitalGainsBasedIncentiveFeesPercentage" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_InvestmentCompanyCapitalGainsBasedIncentiveFeesPaidToTheAdviser" abstract="false" name="InvestmentCompanyCapitalGainsBasedIncentiveFeesPaidToTheAdviser" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_InvestmentCompanyCapitalGainsBasedIncentiveFeesPayable" abstract="false" name="InvestmentCompanyCapitalGainsBasedIncentiveFeesPayable" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_InvestmentCompanyCreditsToFeesFromAdviserOther" abstract="false" name="InvestmentCompanyCreditsToFeesFromAdviserOther" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_NetBaseManagementFee" abstract="false" name="NetBaseManagementFee" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_InvestmentCompanyCreditsToBaseManagementFeeLoanServicingFee" abstract="false" name="InvestmentCompanyCreditsToBaseManagementFeeLoanServicingFee" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_NetLoanServicingFee" abstract="false" name="NetLoanServicingFee" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_InvestmentCompanyCreditsToIncentiveFeesFromAdviserOther" abstract="false" name="InvestmentCompanyCreditsToIncentiveFeesFromAdviserOther" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_BaseManagementFeeAndLoanServicingFeeDueToAdviserMember" abstract="true" name="BaseManagementFeeAndLoanServicingFeeDueToAdviserMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_IncentiveFeeDueToAdviserMember" abstract="true" name="IncentiveFeeDueToAdviserMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_OtherDueToAdviserMember" abstract="true" name="OtherDueToAdviserMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_InvestmentCompanyBaseManagementAndLoanServicingFeeDueToAdviserNetOfCredits" abstract="false" name="InvestmentCompanyBaseManagementAndLoanServicingFeeDueToAdviserNetOfCredits" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_CapitalGainsBasedIncentiveFee" abstract="false" name="CapitalGainsBasedIncentiveFee" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_RevolvingLineOfCreditMember" abstract="true" name="RevolvingLineOfCreditMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_SecuredOvernightFinancingRateSOFRAdjustmentMember" abstract="true" name="SecuredOvernightFinancingRateSOFRAdjustmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_SecuredOvernightFinancingRateSOFRTrancheOneMember" abstract="true" name="SecuredOvernightFinancingRateSOFRTrancheOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_SecuredOvernightFinancingRateSOFRTrancheTwoMember" abstract="true" name="SecuredOvernightFinancingRateSOFRTrancheTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_SecuredOvernightFinancingRateSOFRThereafterMember" abstract="true" name="SecuredOvernightFinancingRateSOFRThereafterMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_DebtCovenantsAxis" abstract="true" name="DebtCovenantsAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="gain_DebtCovenantsDomain" abstract="true" name="DebtCovenantsDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_LessThanOrEqualTo50OfCommitmentMember" abstract="true" name="LessThanOrEqualTo50OfCommitmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_GreaterThan50ButLessThanOrEqualTo65OfCommitmentMember" abstract="true" name="GreaterThan50ButLessThanOrEqualTo65OfCommitmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_GreaterThan65OfCommitmentMember" abstract="true" name="GreaterThan65OfCommitmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_DebtInstrumentVariableRateFloor" abstract="false" name="DebtInstrumentVariableRateFloor" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_DebtInstrumentCovenantRequiredMinimumNetWorthOfMandatoryRedeemableTermPreferredStock" abstract="false" name="DebtInstrumentCovenantRequiredMinimumNetWorthOfMandatoryRedeemableTermPreferredStock" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_DebtInstrumentCovenantRequiredMinimumNetWorthOfMandatoryRedeemableTermPreferredStockPlusPercentOfAllEquityAndSubordinatedDebtRaised" abstract="false" name="DebtInstrumentCovenantRequiredMinimumNetWorthOfMandatoryRedeemableTermPreferredStockPlusPercentOfAllEquityAndSubordinatedDebtRaised" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_DebtInstrumentCovenantRequiredMinimumNetWorthOfMandatoryRedeemableTermPreferredStockMinusPercentOfAnyEquityOrSubordinatedDebtRedeemedOrRetired" abstract="false" name="DebtInstrumentCovenantRequiredMinimumNetWorthOfMandatoryRedeemableTermPreferredStockMinusPercentOfAnyEquityOrSubordinatedDebtRedeemedOrRetired" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_DebtInstrumentCovenantNetWorthOfMandatoryRedeemableTermPreferredStockPlusPercentOfAllEquityAndSubordinatedDebtRaisedMinusAnyEquityOrSubordinatedDebtRedeemedOrRetired" abstract="false" name="DebtInstrumentCovenantNetWorthOfMandatoryRedeemableTermPreferredStockPlusPercentOfAllEquityAndSubordinatedDebtRaisedMinusAnyEquityOrSubordinatedDebtRedeemedOrRetired" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_InvestmentCompanySeniorSecurityIndebtednessAssetCoverageAmount" abstract="false" name="InvestmentCompanySeniorSecurityIndebtednessAssetCoverageAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityUnrealizedAppreciationDepreciation" abstract="false" name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityUnrealizedAppreciationDepreciation" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_A500NotesDue2026Member" abstract="true" name="A500NotesDue2026Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_A800NotesDue2028Member" abstract="true" name="A800NotesDue2028Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_A6.875NotesDue2028Member" abstract="true" name="A6.875NotesDue2028Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_NumberOfNotesOutstanding" abstract="false" name="NumberOfNotesOutstanding" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="gain_DebtInstrumentPrincipalAmountPerNote" abstract="false" name="DebtInstrumentPrincipalAmountPerNote" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="gain_RegistrationStatementOnFormN2FileNo.333277452Member" abstract="true" name="RegistrationStatementOnFormN2FileNo.333277452Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_CommonStockATMProgram2024Member" abstract="true" name="CommonStockATMProgram2024Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_CommonStockATMProgram2022Member" abstract="true" name="CommonStockATMProgram2022Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_SaleOfStockAggregateValueOfSecuritiesAuthorized" abstract="false" name="SaleOfStockAggregateValueOfSecuritiesAuthorized" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_SaleOfStockRemainingCapacityOfAggregateValueOfSecuritiesAuthorized" abstract="false" name="SaleOfStockRemainingCapacityOfAggregateValueOfSecuritiesAuthorized" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_SaleOfStockAggregateOfferingPriceAuthorized" abstract="false" name="SaleOfStockAggregateOfferingPriceAuthorized" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_SaleOfStockRemainingCapacityOfAuthorizedOfferingPrice" abstract="false" name="SaleOfStockRemainingCapacityOfAuthorizedOfferingPrice" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_SaleOfStockWeightedAverageGrossPricePerShare" abstract="false" name="SaleOfStockWeightedAverageGrossPricePerShare" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="gain_SaleOfStockWeightedAverageNetPricePerShareAfterDeductingCommissionsAndOfferingCosts" abstract="false" name="SaleOfStockWeightedAverageNetPricePerShareAfterDeductingCommissionsAndOfferingCosts" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="gain_InvestmentCompanyCashDistributionsPaidToCommonStockholdersFromOrdinaryIncomePercent" abstract="false" name="InvestmentCompanyCashDistributionsPaidToCommonStockholdersFromOrdinaryIncomePercent" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_InvestmentCompanyCashDistributionsPaidToCommonStockholdersFromCapitalGainsPercent" abstract="false" name="InvestmentCompanyCashDistributionsPaidToCommonStockholdersFromCapitalGainsPercent" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_InvestmentCompanyDistributionsPaidSubsequentToFiscalYearEndClassifiedInPriorYearOrdinaryIncome" abstract="false" name="InvestmentCompanyDistributionsPaidSubsequentToFiscalYearEndClassifiedInPriorYearOrdinaryIncome" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_InvestmentCompanyDistributionPaidSubsequentToFiscalYearEndClassifiedInPriorYearCapitalLoss" abstract="false" name="InvestmentCompanyDistributionPaidSubsequentToFiscalYearEndClassifiedInPriorYearCapitalLoss" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_InvestmentCompanyDistributionPaidSubsequentToFiscalYearEndClassifiedInPriorYearCapitalGains" abstract="false" name="InvestmentCompanyDistributionPaidSubsequentToFiscalYearEndClassifiedInPriorYearCapitalGains" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_InvestmentCompanyDeemedDistributionApproachNoticePeriod" abstract="false" name="InvestmentCompanyDeemedDistributionApproachNoticePeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="gain_O2026M1DividendsMember" abstract="true" name="O2026M1DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2026M2DividendsMember" abstract="true" name="O2026M2DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2026M3DividendsMember" abstract="true" name="O2026M3DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2026M4DividendsMember" abstract="true" name="O2026M4DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2026M5DividendsMember" abstract="true" name="O2026M5DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2026M6DividendsMember" abstract="true" name="O2026M6DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2026M7DividendsMember" abstract="true" name="O2026M7DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2026M8DividendsMember" abstract="true" name="O2026M8DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2026M9DividendsMember" abstract="true" name="O2026M9DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2026M10DividendsMember" abstract="true" name="O2026M10DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2026M11DividendsMember" abstract="true" name="O2026M11DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2026M12DividendsMember" abstract="true" name="O2026M12DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2025M1DividendsMember" abstract="true" name="O2025M1DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2025M2DividendsMember" abstract="true" name="O2025M2DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2025M3DividendsMember" abstract="true" name="O2025M3DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2025M4DividendsMember" abstract="true" name="O2025M4DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2025M5DividendsMember" abstract="true" name="O2025M5DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2025M6DividendsMember" abstract="true" name="O2025M6DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2025M7DividendsMember" abstract="true" name="O2025M7DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2025M8DividendsMember" abstract="true" name="O2025M8DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2025M9DividendsMember" abstract="true" name="O2025M9DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2025M10DividendsMember" abstract="true" name="O2025M10DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2025M11DividendsMember" abstract="true" name="O2025M11DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2025M12DividendsMember" abstract="true" name="O2025M12DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2024M1DividendsMember" abstract="true" name="O2024M1DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2024M2DividendsMember" abstract="true" name="O2024M2DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2024M3DividendsMember" abstract="true" name="O2024M3DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2024M4DividendsMember" abstract="true" name="O2024M4DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2024M5DividendsMember" abstract="true" name="O2024M5DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2024M6DividendsMember" abstract="true" name="O2024M6DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2024M7DividendsMember" abstract="true" name="O2024M7DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2024M8DividendsMember" abstract="true" name="O2024M8DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2024M9DividendsMember" abstract="true" name="O2024M9DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2024M10DividendsMember" abstract="true" name="O2024M10DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2024M11DividendsMember" abstract="true" name="O2024M11DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2024M12DividendsMember" abstract="true" name="O2024M12DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_CommonStockDividendsPerSharePaidOrdinary" abstract="false" name="CommonStockDividendsPerSharePaidOrdinary" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="gain_CommonStockDividendsPerSharePaidSupplemental" abstract="false" name="CommonStockDividendsPerSharePaidSupplemental" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="gain_CumulativeUnrealizedAppreciationOfInvestments" abstract="false" name="CumulativeUnrealizedAppreciationOfInvestments" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_InvestmentCompanyDistributableEarningsLossAccumulatedDepreciationOther" abstract="false" name="InvestmentCompanyDistributableEarningsLossAccumulatedDepreciationOther" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_InvestmentCompanyDistributableEarningsLossAccumulatedOtherTemporaryDifferences" abstract="false" name="InvestmentCompanyDistributableEarningsLossAccumulatedOtherTemporaryDifferences" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_AccumulatedLongTermCapitalGainsMember" abstract="true" name="AccumulatedLongTermCapitalGainsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_InvestmentCompanyTargetPercentageOfTaxableIncomeToDistributeToShareholders" abstract="false" name="InvestmentCompanyTargetPercentageOfTaxableIncomeToDistributeToShareholders" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_InvestmentCompanyPercentageOfOrdinaryIncomeDistribution" abstract="false" name="InvestmentCompanyPercentageOfOrdinaryIncomeDistribution" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_InvestmentCompanyPercentageOfNetCapitalGainsDistribution" abstract="false" name="InvestmentCompanyPercentageOfNetCapitalGainsDistribution" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_InvestmentCompanyExciseTax" abstract="false" name="InvestmentCompanyExciseTax" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_InvestmentCompanyPerShareDataAbstract" abstract="true" name="InvestmentCompanyPerShareDataAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="gain_InvestmentCompanyTaxesOnDeemedDistributionsOfLongTermCapitalGainsPerCommonShare" abstract="false" name="InvestmentCompanyTaxesOnDeemedDistributionsOfLongTermCapitalGainsPerCommonShare" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="gain_EffectOfEquityCapitalActivityAbstract" abstract="true" name="EffectOfEquityCapitalActivityAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="gain_InvestmentCompanyDiscountsCommissionsAndOfferingCostsPerShare" abstract="false" name="InvestmentCompanyDiscountsCommissionsAndOfferingCostsPerShare" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="gain_NetAccretiveDilutiveEffectOfEquityOfferingPerShare" abstract="false" name="NetAccretiveDilutiveEffectOfEquityOfferingPerShare" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="gain_InvestmentCompanyNetAssetValuePerShareOtherIncreaseDecreaseNet" abstract="false" name="InvestmentCompanyNetAssetValuePerShareOtherIncreaseDecreaseNet" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="gain_StatementOfAssetsAndLiabilitiesDataAbstract" abstract="true" name="StatementOfAssetsAndLiabilitiesDataAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="gain_SeniorSecuritiesDataAbstract" abstract="true" name="SeniorSecuritiesDataAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="gain_InvestmentCompanyRatioOfNetExpensesToAverageNetAssets" abstract="false" name="InvestmentCompanyRatioOfNetExpensesToAverageNetAssets" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="gain_O2027M1DividendsMember" abstract="true" name="O2027M1DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2027M2DividendsMember" abstract="true" name="O2027M2DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_O2027M3DividendsMember" abstract="true" name="O2027M3DividendsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_CommonStockDividendsPerShareDeclaredOrdinary" abstract="false" name="CommonStockDividendsPerShareDeclaredOrdinary" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="gain_InvestmentAffiliateAndControlMember" abstract="true" name="InvestmentAffiliateAndControlMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_DebtAndEquitySecuritiesRealizedGainLossExcludingPortfolioCompaniesNoLongerInThePortfolio" abstract="false" name="DebtAndEquitySecuritiesRealizedGainLossExcludingPortfolioCompaniesNoLongerInThePortfolio" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="gain_RisksRelatedToTheEconomyMember" abstract="true" name="RisksRelatedToTheEconomyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_RisksRelatedToInterestRatesMember" abstract="true" name="RisksRelatedToInterestRatesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_RisksRelatedToOurInvestmentsMember" abstract="true" name="RisksRelatedToOurInvestmentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_RisksRelatedToOurExternalFinancingMember" abstract="true" name="RisksRelatedToOurExternalFinancingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_RisksRelatedToOurRegulationAndStructureMember" abstract="true" name="RisksRelatedToOurRegulationAndStructureMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_RisksRelatedToOurExternalManagementMember" abstract="true" name="RisksRelatedToOurExternalManagementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_RisksRelatedToAnInvestmentInOurSecuritiesMember" abstract="true" name="RisksRelatedToAnInvestmentInOurSecuritiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_RisksRelatedToThe5.002026Notes4.8752028NotesAnd8.002028NotesCollectivelyTheNotesMember" abstract="true" name="RisksRelatedToThe5.002026Notes4.8752028NotesAnd8.002028NotesCollectivelyTheNotesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_GeneralRiskFactorsMember" abstract="true" name="GeneralRiskFactorsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_A675SeriesBCumulativeTermPreferredStockMember" abstract="true" name="A675SeriesBCumulativeTermPreferredStockMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_A650SeriesCCumulativeTermPreferredStockDue2022Member" abstract="true" name="A650SeriesCCumulativeTermPreferredStockDue2022Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_A625SeriesDCumulativeTermPreferredStockDue2023Member" abstract="true" name="A625SeriesDCumulativeTermPreferredStockDue2023Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_A6375SeriesECumulativeTermPreferredStockDue2025Member" abstract="true" name="A6375SeriesECumulativeTermPreferredStockDue2025Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_Notes2026FivePointZeroMember" abstract="true" name="Notes2026FivePointZeroMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="gain_Notes2028FourPointEightSevenFiveMember" abstract="true" name="Notes2028FourPointEightSevenFiveMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
