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  <xs:element id="obnk_InterestandDividendIncomeSecuritiesOperatingHeldatFinancialInstitutions" abstract="false" name="InterestandDividendIncomeSecuritiesOperatingHeldatFinancialInstitutions" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_BusinessCombinationContingentConsiderationRevenueGrowthObjectivesTerm" abstract="false" name="BusinessCombinationContingentConsiderationRevenueGrowthObjectivesTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossWriteoffOriginatedInCurrentFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossWriteoffOriginatedInCurrentFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_DebtSecuritiesFVNIMember" abstract="true" name="DebtSecuritiesFVNIMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossWriteoffOriginatedFourYearsBeforeLatestFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossWriteoffOriginatedFourYearsBeforeLatestFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossWriteoffOriginatedInFiscalYearBeforeLatestFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossWriteoffOriginatedInFiscalYearBeforeLatestFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_MortgageServicingRightsMember" abstract="true" name="MortgageServicingRightsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossRecoveryOriginatedFiveOrMoreYearsBeforeLatestFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossRecoveryOriginatedFiveOrMoreYearsBeforeLatestFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossWriteoffOriginatedTwoYearsBeforeLatestFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossWriteoffOriginatedTwoYearsBeforeLatestFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_A2012PlanMember" abstract="true" name="A2012PlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_ValuationMethodologyProbabilityOfDefaultMember" abstract="true" name="ValuationMethodologyProbabilityOfDefaultMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_ValuationMethodologyDiscountedCashFlowMember" abstract="true" name="ValuationMethodologyDiscountedCashFlowMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_ClassifiedMember" abstract="true" name="ClassifiedMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_RecognitionOfOperatingLeaseLiability" abstract="false" name="RecognitionOfOperatingLeaseLiability" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_LiabilitytoRepurchaseNonconformingGNMALoans" abstract="false" name="LiabilitytoRepurchaseNonconformingGNMALoans" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_MortgageServicingRightHedgeImpact" abstract="false" name="MortgageServicingRightHedgeImpact" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_DebtSecuritiesFVNIMeasurementInput" abstract="false" name="DebtSecuritiesFVNIMeasurementInput" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="obnk_BankingRegulationTransitionRegulatoryCapitalAmount" abstract="false" name="BankingRegulationTransitionRegulatoryCapitalAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_CommercialCollateralizedMortgageObligationsMember" abstract="true" name="CommercialCollateralizedMortgageObligationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_MortgageBankingRevenue" abstract="false" name="MortgageBankingRevenue" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_RiskParticipationDerivativeMember" abstract="true" name="RiskParticipationDerivativeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossWriteoffRevolving" abstract="false" name="FinancingReceivableAllowanceForCreditLossWriteoffRevolving" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_GainOnSaleOfMortgageLoansIncludingMortgageServicingRightsOrigination" abstract="false" name="GainOnSaleOfMortgageLoansIncludingMortgageServicingRightsOrigination" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_CreditLossExpenseReversal" abstract="false" name="CreditLossExpenseReversal" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_ValuationMethodologyFairValueOfCollateralMember" abstract="true" name="ValuationMethodologyFairValueOfCollateralMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_OriginBankMember" abstract="true" name="OriginBankMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_FairValueOptionAggregateUnpaidPrincipalBalance" abstract="false" name="FairValueOptionAggregateUnpaidPrincipalBalance" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_ServicingFeeIncomeRate" abstract="false" name="ServicingFeeIncomeRate" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="obnk_OtherNoninterestIncomeMember" abstract="true" name="OtherNoninterestIncomeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_LoansAndLeasesReceivableImpairedInterestOnNonaccrualLoans" abstract="false" name="LoansAndLeasesReceivableImpairedInterestOnNonaccrualLoans" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardPerformancePeriod" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardPerformancePeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossRecoveryOriginatedInCurrentFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossRecoveryOriginatedInCurrentFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossRecoveryRevolving" abstract="false" name="FinancingReceivableAllowanceForCreditLossRecoveryRevolving" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FairValueDisclosureOffBalanceSheetRisksAmountLiabilityGreaterThanFiveYears" abstract="false" name="FairValueDisclosureOffBalanceSheetRisksAmountLiabilityGreaterThanFiveYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_ShareBasedCompensationArrangementByShareBasedPaymentAwardTargetPercentage" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardTargetPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="obnk_DerivativeWeightedAverageInterestRate" abstract="false" name="DerivativeWeightedAverageInterestRate" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="obnk_IncreaseDecreaseInObligationRepurchaseObligations" abstract="false" name="IncreaseDecreaseInObligationRepurchaseObligations" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossRecoveryOriginatedFourYearsBeforeLatestFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossRecoveryOriginatedFourYearsBeforeLatestFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_MortgageServicingRightsValuationAdjustmentNetOfAmortization" abstract="false" name="MortgageServicingRightsValuationAdjustmentNetOfAmortization" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryOriginatedTwoYearsBeforeLatestFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryOriginatedTwoYearsBeforeLatestFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_OfficeandOperationsExpense" abstract="false" name="OfficeandOperationsExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_DepreciationandAmortizationExcludingAmortizationofInvestmentPremiumsandDiscountsandQualifiedAffordableHousingProjectsInvestments" abstract="false" name="DepreciationandAmortizationExcludingAmortizationofInvestmentPremiumsandDiscountsandQualifiedAffordableHousingProjectsInvestments" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FairValueDisclosureOffBalanceSheetRisksAmountLiabilityThreeYearsThroughFiveYears" abstract="false" name="FairValueDisclosureOffBalanceSheetRisksAmountLiabilityThreeYearsThroughFiveYears" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_OccupancyNetandEquipmentExpense" abstract="false" name="OccupancyNetandEquipmentExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossRecoveryOriginatedTwoYearsBeforeLatestFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossRecoveryOriginatedTwoYearsBeforeLatestFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossWriteoffOriginatedFiveOrMoreYearsBeforeLatestFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossWriteoffOriginatedFiveOrMoreYearsBeforeLatestFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_ServicingFeesNet1" abstract="false" name="ServicingFeesNet1" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryRevolving" abstract="false" name="FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryRevolving" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FederalHomeLoanBankMember" abstract="true" name="FederalHomeLoanBankMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossRecoveryOriginatedThreeYearsBeforeLatestFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossRecoveryOriginatedThreeYearsBeforeLatestFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_ProductsAndServicesDepositServiceFeesMember" abstract="true" name="ProductsAndServicesDepositServiceFeesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_CombinationMember" abstract="true" name="CombinationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossWriteoffOriginatedFiveYearsBeforeLatestFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossWriteoffOriginatedFiveYearsBeforeLatestFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_MortgageBankingOperationsTableTextBlock" abstract="false" name="MortgageBankingOperationsTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossWriteoffOriginatedThreeYearsBeforeLatestFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossWriteoffOriginatedThreeYearsBeforeLatestFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryOriginatedInCurrentFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryOriginatedInCurrentFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_CommitmentsToExtendCreditUnconditionalCancellableCommitmentsMember" abstract="true" name="CommitmentsToExtendCreditUnconditionalCancellableCommitmentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_ProceedsfromMaturitiesRepaymentsandCallsofEquitySecuritiesFVNI" abstract="false" name="ProceedsfromMaturitiesRepaymentsandCallsofEquitySecuritiesFVNI" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_ResidentialRealEstateLoanMember" abstract="true" name="ResidentialRealEstateLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_PaycheckProtectionProgramMember" abstract="true" name="PaycheckProtectionProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_LoansHeldforSaleMember" abstract="true" name="LoansHeldforSaleMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_ElectronicBankingExpense" abstract="false" name="ElectronicBankingExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryOriginatedFiveYearsBeforeLatestFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryOriginatedFiveYearsBeforeLatestFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_PaymentToAcquireLowIncomeHousingTaxCreditInvestments" abstract="false" name="PaymentToAcquireLowIncomeHousingTaxCreditInvestments" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryOriginatedInFiscalYearBeforeLatestFiscalYear" abstract="false" name="FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryOriginatedInFiscalYearBeforeLatestFiscalYear" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_ConstructionLandandLandDevelopmentLoansMember" abstract="true" name="ConstructionLandandLandDevelopmentLoansMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="obnk_MortgageServicingRightandHedgeFairValueAdjustment" abstract="false" name="MortgageServicingRightandHedgeFairValueAdjustment" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_OtherInvestmentsFairValue" abstract="false" name="OtherInvestmentsFairValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfCategories" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfCategories" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="obnk_BankingRegulationAbstract" abstract="true" name="BankingRegulationAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="obnk_JuniorSubordinatedDebentureOwedtoUnconsolidatedSubsidiaryTrustFairValue" abstract="false" name="JuniorSubordinatedDebentureOwedtoUnconsolidatedSubsidiaryTrustFairValue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForAmortizationOfUnrealizedLossesOnAvailableForSaleSecuritiesTransferredToHeldToMaturityBeforeTax" abstract="false" name="OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForAmortizationOfUnrealizedLossesOnAvailableForSaleSecuritiesTransferredToHeldToMaturityBeforeTax" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FranchiseTaxExpense" abstract="false" name="FranchiseTaxExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_PaymentsForLoanOriginations" abstract="false" name="PaymentsForLoanOriginations" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_ProceedsfromFHLBankBorrowingsShortTermAdvancesFinancingActivities" abstract="false" name="ProceedsfromFHLBankBorrowingsShortTermAdvancesFinancingActivities" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_DebtSecuritiesFVNIAbstract" abstract="true" name="DebtSecuritiesFVNIAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="obnk_MortgageBankingRevenueOriginationsOfMortgageServicingRights" abstract="false" name="MortgageBankingRevenueOriginationsOfMortgageServicingRights" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_FederalHomeLoanBankAdvancesandSecuritiesSoldUnderAgreementstoRepurchaseFairValue" abstract="false" name="FederalHomeLoanBankAdvancesandSecuritiesSoldUnderAgreementstoRepurchaseFairValue" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="obnk_ForwardCommitmenttoPurchaseMember" abstract="true" name="ForwardCommitmenttoPurchaseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
