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  <xs:element id="isba_LoansReceivableAllowanceFairValueDisclosure" abstract="false" name="LoansReceivableAllowanceFairValueDisclosure" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_EquityMethodAndOtherInvestmentsFairValueDisclosure" abstract="false" name="EquityMethodAndOtherInvestmentsFairValueDisclosure" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_BankOwnedLifeInsuranceIncomeFromPolicyRedemption" abstract="false" name="BankOwnedLifeInsuranceIncomeFromPolicyRedemption" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_FinancingReceivableRecordedInvestmentPastDueAndNonaccrualStatus" abstract="false" name="FinancingReceivableRecordedInvestmentPastDueAndNonaccrualStatus" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_FinancingReceivableDebtServicingToGrossIncomeRatioMaximum" abstract="false" name="FinancingReceivableDebtServicingToGrossIncomeRatioMaximum" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="isba_ShareBasedCompensationSharesTransferredFromTrustToCommonStockValue" abstract="false" name="ShareBasedCompensationSharesTransferredFromTrustToCommonStockValue" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_FinancingReceivablePaymentAmountToGrossIncomeRatioMaximum" abstract="false" name="FinancingReceivablePaymentAmountToGrossIncomeRatioMaximum" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="isba_FinancingReceivableLoanToValueRatioMaximum" abstract="false" name="FinancingReceivableLoanToValueRatioMaximum" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="isba_ResidentialSeniorLiensFinancingReceivableMember" abstract="true" name="ResidentialSeniorLiensFinancingReceivableMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_LowSatisfactoryRatingMember" abstract="true" name="LowSatisfactoryRatingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_FinancingReceivableTerm" abstract="false" name="FinancingReceivableTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="isba_AuctionRateMoneyMarketPreferredStocksMember" abstract="true" name="AuctionRateMoneyMarketPreferredStocksMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesAndLoansReceivablePledgedAsCollateral" abstract="false" name="PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesAndLoansReceivablePledgedAsCollateral" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesAndLoansReceivableForFederalHomeLoanBankDebtAndFederalReserveBankDiscountWindow" abstract="false" name="PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesAndLoansReceivableForFederalHomeLoanBankDebtAndFederalReserveBankDiscountWindow" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_ImpairedFinancingReceivableFairValueDisclosureAppraisedValueWeightedAverage" abstract="false" name="ImpairedFinancingReceivableFairValueDisclosureAppraisedValueWeightedAverage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="isba_FinancingReceivableThresholdPeriodWriteoff" abstract="false" name="FinancingReceivableThresholdPeriodWriteoff" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="isba_LoansandLeasesReceivableGrossCommercialExcludingAgriculturalandAgriculturalRealEstate" abstract="false" name="LoansandLeasesReceivableGrossCommercialExcludingAgriculturalandAgriculturalRealEstate" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_AvailableforsaleSecuritiesWithVariableMonthlyPaymentsOrWithoutSingleMaturityDateFairValue" abstract="false" name="AvailableforsaleSecuritiesWithVariableMonthlyPaymentsOrWithoutSingleMaturityDateFairValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_ResidentialJuniorLiensFinancingReceivableMember" abstract="true" name="ResidentialJuniorLiensFinancingReceivableMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_CommercialAdvancestoMortgageBrokersSegmentMember" abstract="true" name="CommercialAdvancestoMortgageBrokersSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_ScheduleofDebtLineItems" abstract="true" name="ScheduleofDebtLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="isba_MembershipsAndSubscriptionsExpense" abstract="false" name="MembershipsAndSubscriptionsExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_AvailableforsaleSecuritiesWithVariableMonthlyPaymentsOrWithoutSingleMaturityDateAmortizedCostBasis" abstract="false" name="AvailableforsaleSecuritiesWithVariableMonthlyPaymentsOrWithoutSingleMaturityDateAmortizedCostBasis" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_ServiceChargesAndDepositAccountFeesMember" abstract="true" name="ServiceChargesAndDepositAccountFeesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_FederalHomeLoanBankAdvancesFixedRateDue2022Member" abstract="true" name="FederalHomeLoanBankAdvancesFixedRateDue2022Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_LossMember" abstract="true" name="LossMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_OtherRealEstateForeclosedAssetsandRepossessedAssetsValuationAdjustments" abstract="false" name="OtherRealEstateForeclosedAssetsandRepossessedAssetsValuationAdjustments" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_IncomeBeforeEquityInUndistributedNetIncomeOfSubsidiary" abstract="false" name="IncomeBeforeEquityInUndistributedNetIncomeOfSubsidiary" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_IsabellaBankCorporationRestrictedStockPlanMember" abstract="true" name="IsabellaBankCorporationRestrictedStockPlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_ForeclosedAssetMember" abstract="true" name="ForeclosedAssetMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_DividendIncomeReceivedFromSubsidiary" abstract="false" name="DividendIncomeReceivedFromSubsidiary" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_FinancingReceivableNonperformingNonaccrualOfInterestThresholdPeriod" abstract="false" name="FinancingReceivableNonperformingNonaccrualOfInterestThresholdPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="isba_PercentageOfReportableSegmentAssetsAndOperatingResults" abstract="false" name="PercentageOfReportableSegmentAssetsAndOperatingResults" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="isba_LoanandLeasesReceivableGrossConsumerOther" abstract="false" name="LoanandLeasesReceivableGrossConsumerOther" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_ShortTermDebtWeightedAverageInterestRates" abstract="false" name="ShortTermDebtWeightedAverageInterestRates" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="isba_ConsumerSecuredFinancingReceivableMember" abstract="true" name="ConsumerSecuredFinancingReceivableMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_Printingandsuppliesexpense" abstract="false" name="Printingandsuppliesexpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_LoansReceivableCollateralizedByLivestockMember" abstract="true" name="LoansReceivableCollateralizedByLivestockMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_DepositsWithStatedMaturitiesFairValueDisclosure" abstract="false" name="DepositsWithStatedMaturitiesFairValueDisclosure" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_FinancingReceivableAmountAdditionalApprovalThreshold" abstract="false" name="FinancingReceivableAmountAdditionalApprovalThreshold" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_OtherNoninterestExpenseMiscellaneous" abstract="false" name="OtherNoninterestExpenseMiscellaneous" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_ImpairedFinancingReceivableFairValueDisclosure" abstract="false" name="ImpairedFinancingReceivableFairValueDisclosure" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_EducationAndTravelExpense" abstract="false" name="EducationAndTravelExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_DeferredCompensationArrangementwithIndividualDeferredCompensationObligations" abstract="false" name="DeferredCompensationArrangementwithIndividualDeferredCompensationObligations" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_ResidentialHomeEquityLineOfCreditFinancingReceivableMember" abstract="true" name="ResidentialHomeEquityLineOfCreditFinancingReceivableMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_IncomeLossBeforeIncomeTaxesandEquityinUndistributedNetIncomeofSubsidiary" abstract="false" name="IncomeLossBeforeIncomeTaxesandEquityinUndistributedNetIncomeofSubsidiary" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_PaymentsForRepurchaseOfCommonStockExcludingStockForDeferredCompensationObligations" abstract="false" name="PaymentsForRepurchaseOfCommonStockExcludingStockForDeferredCompensationObligations" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_PaymentsForProceedsFromLoanAndLeaseOriginationsAndPrincipalCollections" abstract="false" name="PaymentsForProceedsFromLoanAndLeaseOriginationsAndPrincipalCollections" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_AgriculturalPortfolioSegmentMember" abstract="true" name="AgriculturalPortfolioSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_CommercialAndAgriculturalPortfolioSegmentMember" abstract="true" name="CommercialAndAgriculturalPortfolioSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_ManagementFeesAndOtherIncome" abstract="false" name="ManagementFeesAndOtherIncome" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_NoninterestIncomeInvestmentandTrustAdvisoryFees" abstract="false" name="NoninterestIncomeInvestmentandTrustAdvisoryFees" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_CertificatesOfDepositUnderOtherSavings" abstract="false" name="CertificatesOfDepositUnderOtherSavings" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_RealEstateOwnedMember" abstract="true" name="RealEstateOwnedMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfEmployeeAnnualSalary" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfEmployeeAnnualSalary" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="isba_ForeclosedAssetsFairValueDisclosure" abstract="false" name="ForeclosedAssetsFairValueDisclosure" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_FinancingReceivableCreditQualityDelinquencyPeriod" abstract="false" name="FinancingReceivableCreditQualityDelinquencyPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="isba_ATMandDebitCardExpense" abstract="false" name="ATMandDebitCardExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_BankOwnedLifeInsuranceIncomeNetofExpense" abstract="false" name="BankOwnedLifeInsuranceIncomeNetofExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_IncreaseDecreaseinInterestPayableAndOtherAccruedLiabilities" abstract="false" name="IncreaseDecreaseinInterestPayableAndOtherAccruedLiabilities" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isba_IsabellaBankCorporationAndRelatedCompaniesDeferredCompensationPlanForDirectorsMember" abstract="true" name="IsabellaBankCorporationAndRelatedCompaniesDeferredCompensationPlanForDirectorsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isba_AgriculturalRealEstatePortfolioSegmentMember" abstract="true" name="AgriculturalRealEstatePortfolioSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
