false--12-31 Q1 2020 0000719220 0.0550 0.20 0.0475 0.00 0.17 0.00 0 0.27 0.28 2.50 2.50 50000000 50000000 41449444 41449444 39560304 39125425 0 0 124491000 113505000 22100000 0 0 0 0.1274 0.1254 0.0746 0.0939 0.1274 0.1254 0.0746 0.0939 39834 26739 0 3290 1889140 2324019 313904 411430 Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.Reclassification adjustments are comprised of realized security gains or losses. The realized gains or losses have been reclassified out of accumulated other comprehensive income/(loss) and have affected certain lines in the Consolidated Statements of Comprehensive Income as follows: the pre-tax amount is included in securities gains/losses-net, the tax expense amount is included in the provision for income taxes and the net of tax amount is included in net income. There were no reclassification adjustments for the three months ended March 31, 2020 or 2019.Refer to Note 1, Basis of Presentation for details of reclassification of our portfolio segments related to the adoption of ASU 2016-13 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instrument.Consumer bankruptcy loans where the debt has been legally discharged through the bankruptcy court and not reaffirmed.As reported in the Consolidated Balance Sheets 0000719220 2020-01-01 2020-03-31 0000719220 2020-05-08 0000719220 2019-12-31 0000719220 2020-03-31 0000719220 2019-01-01 2019-03-31 0000719220 stba:WealthManagementMember 2019-01-01 2019-03-31 0000719220 us-gaap:CreditAndDebitCardMember 2019-01-01 2019-03-31 0000719220 stba:WealthManagementMember 2020-01-01 2020-03-31 0000719220 us-gaap:DepositAccountMember 2020-01-01 2020-03-31 0000719220 us-gaap:DepositAccountMember 2019-01-01 2019-03-31 0000719220 us-gaap:CreditAndDebitCardMember 2020-01-01 2020-03-31 0000719220 us-gaap:AccountingStandardsUpdate201613Member 2020-01-01 0000719220 2018-12-31 0000719220 us-gaap:AdditionalPaidInCapitalMember 2020-03-31 0000719220 us-gaap:CommonStockMember 2019-03-31 0000719220 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-01-01 2019-03-31 0000719220 us-gaap:TreasuryStockMember 2019-01-01 2019-03-31 0000719220 us-gaap:RetainedEarningsMember 2019-01-01 2019-03-31 0000719220 us-gaap:RetainedEarningsMember 2019-03-31 0000719220 us-gaap:AdditionalPaidInCapitalMember 2019-12-31 0000719220 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2018-12-31 0000719220 us-gaap:TreasuryStockMember 2020-01-01 2020-03-31 0000719220 us-gaap:TreasuryStockMember 2020-03-31 0000719220 us-gaap:AdditionalPaidInCapitalMember 2018-12-31 0000719220 us-gaap:AccountingStandardsUpdate201602Member 2019-01-01 0000719220 us-gaap:TreasuryStockMember 2019-03-31 0000719220 us-gaap:RetainedEarningsMember 2020-01-01 2020-03-31 0000719220 us-gaap:AdditionalPaidInCapitalMember 2020-01-01 2020-03-31 0000719220 us-gaap:AccountingStandardsUpdate201613Member us-gaap:RetainedEarningsMember 2020-01-01 0000719220 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2020-01-01 2020-03-31 0000719220 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2020-03-31 0000719220 us-gaap:AccountingStandardsUpdate201602Member us-gaap:RetainedEarningsMember 2019-01-01 0000719220 us-gaap:RetainedEarningsMember 2018-12-31 0000719220 us-gaap:RetainedEarningsMember 2020-03-31 0000719220 us-gaap:TreasuryStockMember 2018-12-31 0000719220 us-gaap:AdditionalPaidInCapitalMember 2019-03-31 0000719220 2019-03-31 0000719220 us-gaap:CommonStockMember 2020-03-31 0000719220 us-gaap:AdditionalPaidInCapitalMember 2019-01-01 2019-03-31 0000719220 us-gaap:RetainedEarningsMember 2019-12-31 0000719220 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-03-31 0000719220 us-gaap:CommonStockMember 2019-12-31 0000719220 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-12-31 0000719220 us-gaap:CommonStockMember 2018-12-31 0000719220 us-gaap:TreasuryStockMember 2019-12-31 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember us-gaap:ConsumerPortfolioSegmentMember stba:OtherConsumerMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember 2020-01-01 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerRealEstateMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember us-gaap:ConsumerPortfolioSegmentMember stba:OtherConsumerMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember 2020-01-01 0000719220 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember 2020-01-01 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerRealEstateMember 2020-01-01 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember 2020-01-01 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember 2020-01-01 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember 2020-01-01 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:OtherConsumerMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerRealEstateMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember us-gaap:RetainedEarningsMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember stba:DNBFinancialCorporationMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember stba:CommercialAndIndustrialMember 2020-01-01 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember stba:STLegacyLoanMember 2020-01-01 0000719220 stba:DNBFinancialCorporationMember 2020-01-01 2020-03-31 0000719220 stba:DNBFinancialCorporationMember 2019-01-01 2019-12-31 0000719220 stba:DNBFinancialCorporationMember 2020-03-31 0000719220 stba:DNBFinancialCorporationMember 2019-11-30 2019-11-30 0000719220 stba:DNBFinancialCorporationMember 2019-11-30 0000719220 stba:DNBFinancialCorporationMember 2019-12-01 2020-03-31 0000719220 stba:DNBFinancialCorporationMember stba:WealthManagementMember 2020-03-31 0000719220 stba:DNBFinancialCorporationMember us-gaap:CoreDepositsMember 2020-03-31 0000719220 stba:DNBFinancialCorporationPreAcquisitionMember 2019-11-30 0000719220 stba:DNBFinancialCorporationMember us-gaap:CoreDepositsMember 2019-12-01 2020-03-31 0000719220 stba:DNBFinancialCorporationMember stba:WealthManagementMember 2019-12-01 2020-03-31 0000719220 stba:DNBFinancialCorporationMember us-gaap:CoreDepositsMember 2019-11-30 0000719220 stba:DNBFinancialCorporationMember stba:WealthManagementMember 2019-11-30 0000719220 us-gaap:RestrictedStockMember 2019-01-01 2019-03-31 0000719220 us-gaap:RestrictedStockMember 2020-01-01 2020-03-31 0000719220 us-gaap:EstimateOfFairValueFairValueDisclosureMember 2020-03-31 0000719220 us-gaap:CarryingReportedAmountFairValueDisclosureMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:EstimateOfFairValueFairValueDisclosureMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:EstimateOfFairValueFairValueDisclosureMember 2020-03-31 0000719220 us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:InterestRateLockCommitmentsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateLockCommitmentsMember 2020-03-31 0000719220 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:ForwardContractsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateSwapMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:ForwardContractsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateLockCommitmentsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:ForwardContractsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateSwapMember 2020-03-31 0000719220 us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:InterestRateSwapMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:ForwardContractsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateSwapMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateLockCommitmentsMember 2020-03-31 0000719220 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateLockCommitmentsMember 2020-03-31 0000719220 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateSwapMember 2020-03-31 0000719220 us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:ForwardContractsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CollateralizedMortgageObligationsMember 2019-12-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:ResidentialMortgageBackedSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentCorporationsAndAgenciesSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember 2019-12-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateLockCommitmentsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateLockCommitmentsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateSwapMember 2019-12-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialMortgageBackedSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USStatesAndPoliticalSubdivisionsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ForwardContractsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateSwapMember 2019-12-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:CorporateBondSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ResidentialMortgageBackedSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USStatesAndPoliticalSubdivisionsMember 2019-12-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateSwapMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ResidentialMortgageBackedSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentCorporationsAndAgenciesSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CollateralizedMortgageObligationsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ForwardContractsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateLockCommitmentsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateSwapMember 2019-12-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:CollateralizedMortgageObligationsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialMortgageBackedSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USStatesAndPoliticalSubdivisionsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialMortgageBackedSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CorporateBondSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ResidentialMortgageBackedSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialMortgageBackedSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CorporateBondSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasurySecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentCorporationsAndAgenciesSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CollateralizedMortgageObligationsMember 2019-12-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:USStatesAndPoliticalSubdivisionsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasurySecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasurySecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CorporateBondSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:ForwardContractsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentCorporationsAndAgenciesSecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateLockCommitmentsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ForwardContractsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasurySecuritiesMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember stba:ValuationTechniqueCollateralMethodMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:MeasurementInputCostToSellMember stba:ValuationTechniqueCollateralMethodMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember 2019-12-31 0000719220 us-gaap:EstimateOfFairValueFairValueDisclosureMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:EstimateOfFairValueFairValueDisclosureMember 2019-12-31 0000719220 us-gaap:CarryingReportedAmountFairValueDisclosureMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:EstimateOfFairValueFairValueDisclosureMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:ForwardContractsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateSwapMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember 2019-12-31 0000719220 us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:InterestRateSwapMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateLockCommitmentsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateLockCommitmentsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:ForwardContractsMember 2019-12-31 0000719220 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:ForwardContractsMember 2019-12-31 0000719220 us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:InterestRateLockCommitmentsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateSwapMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateSwapMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateLockCommitmentsMember 2019-12-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:ForwardContractsMember 2019-12-31 0000719220 us-gaap:CarryingReportedAmountFairValueDisclosureMember us-gaap:ForwardContractsMember 2019-12-31 0000719220 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateSwapMember 2019-12-31 0000719220 us-gaap:EstimateOfFairValueFairValueDisclosureMember us-gaap:InterestRateLockCommitmentsMember 2019-12-31 0000719220 us-gaap:FairValueMeasurementsNonrecurringMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CollateralizedMortgageObligationsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USStatesAndPoliticalSubdivisionsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ForwardContractsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateSwapMember 2020-03-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialMortgageBackedSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember 2020-03-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:CollateralizedMortgageObligationsMember 2020-03-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:ForwardContractsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialMortgageBackedSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasurySecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialMortgageBackedSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ResidentialMortgageBackedSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateSwapMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ForwardContractsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ForwardContractsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateLockCommitmentsMember 2020-03-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember 2020-03-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentCorporationsAndAgenciesSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasurySecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:ResidentialMortgageBackedSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateLockCommitmentsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CorporateBondSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CollateralizedMortgageObligationsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentCorporationsAndAgenciesSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentCorporationsAndAgenciesSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentCorporationsAndAgenciesSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateLockCommitmentsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CorporateBondSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USStatesAndPoliticalSubdivisionsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasurySecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:CorporateBondSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateLockCommitmentsMember 2020-03-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateSwapMember 2020-03-31 0000719220 us-gaap:FairValueMeasurementsRecurringMember us-gaap:USStatesAndPoliticalSubdivisionsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:InterestRateSwapMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USTreasurySecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ResidentialMortgageBackedSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CorporateBondSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USStatesAndPoliticalSubdivisionsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:ResidentialMortgageBackedSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CollateralizedMortgageObligationsMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialMortgageBackedSecuritiesMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember stba:MeasurementInputContractualLoanRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:MeasurementInputCostToSellMember stba:ValuationTechniqueCollateralMethodMember 2020-03-31 0000719220 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember stba:ValuationTechniqueCollateralMethodMember 2020-03-31 0000719220 us-gaap:FairValueMeasurementsNonrecurringMember 2019-12-31 0000719220 srt:MinimumMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2019-12-31 0000719220 srt:MaximumMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:MeasurementInputConstantPrepaymentRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2019-12-31 0000719220 srt:MinimumMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:MeasurementInputCostToSellMember stba:ValuationTechniqueCollateralMethodMember 2019-12-31 0000719220 srt:MinimumMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember stba:MeasurementInputContractualLoanRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2019-12-31 0000719220 srt:MinimumMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:MeasurementInputConstantPrepaymentRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2019-12-31 0000719220 srt:MaximumMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2019-12-31 0000719220 srt:MaximumMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember stba:MeasurementInputContractualLoanRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2019-12-31 0000719220 srt:MaximumMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:MeasurementInputCostToSellMember stba:ValuationTechniqueCollateralMethodMember 2019-12-31 0000719220 srt:MinimumMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:MeasurementInputConstantPrepaymentRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2020-03-31 0000719220 srt:MaximumMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:MeasurementInputConstantPrepaymentRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2020-03-31 0000719220 srt:MinimumMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2020-03-31 0000719220 srt:MaximumMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:MeasurementInputCostToSellMember stba:ValuationTechniqueCollateralMethodMember 2020-03-31 0000719220 srt:MinimumMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:MeasurementInputCostToSellMember stba:ValuationTechniqueCollateralMethodMember 2020-03-31 0000719220 srt:MaximumMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsNonrecurringMember us-gaap:MeasurementInputDiscountRateMember us-gaap:ValuationTechniqueDiscountedCashFlowMember 2020-03-31 0000719220 us-gaap:ResidentialMortgageBackedSecuritiesMember 2020-03-31 0000719220 us-gaap:CollateralizedMortgageObligationsMember 2020-03-31 0000719220 us-gaap:CorporateBondSecuritiesMember 2020-03-31 0000719220 us-gaap:CommercialMortgageBackedSecuritiesMember 2020-03-31 0000719220 us-gaap:USStatesAndPoliticalSubdivisionsMember 2020-03-31 0000719220 us-gaap:USGovernmentCorporationsAndAgenciesSecuritiesMember 2020-03-31 0000719220 us-gaap:USGovernmentCorporationsAndAgenciesSecuritiesMember 2019-12-31 0000719220 us-gaap:ResidentialMortgageBackedSecuritiesMember 2019-12-31 0000719220 us-gaap:CorporateDebtSecuritiesMember 2020-03-31 0000719220 us-gaap:USTreasurySecuritiesMember 2019-12-31 0000719220 us-gaap:CommercialMortgageBackedSecuritiesMember 2019-12-31 0000719220 us-gaap:CollateralizedMortgageObligationsMember 2019-12-31 0000719220 us-gaap:USStatesAndPoliticalSubdivisionsMember 2019-12-31 0000719220 us-gaap:USTreasurySecuritiesMember 2020-03-31 0000719220 us-gaap:CorporateDebtSecuritiesMember 2019-12-31 0000719220 us-gaap:CorporateBondSecuritiesMember 2019-12-31 0000719220 us-gaap:HomeEquityLoanMember 2019-01-01 2019-03-31 0000719220 us-gaap:HomeEquityLoanMember us-gaap:ContractualInterestRateReductionMember 2019-01-01 2019-03-31 0000719220 stba:MaturityDateExtensionAndInterestRateReductionMember 2019-01-01 2019-03-31 0000719220 stba:BankruptcyMember 2019-01-01 2019-03-31 0000719220 us-gaap:ResidentialMortgageMember 2019-01-01 2019-03-31 0000719220 stba:CommercialAndIndustrialMember stba:PaymentDeferralAndExtendedMaturityMember 2019-01-01 2019-03-31 0000719220 us-gaap:HomeEquityLoanMember stba:MaturityDateExtensionAndPaymentReductionMember 2019-01-01 2019-03-31 0000719220 stba:CommercialAndIndustrialMember 2019-01-01 2019-03-31 0000719220 us-gaap:ContractualInterestRateReductionMember 2019-01-01 2019-03-31 0000719220 us-gaap:HomeEquityLoanMember stba:BankruptcyMember 2019-01-01 2019-03-31 0000719220 stba:CommercialAndIndustrialMember stba:MaturityDateExtensionAndInterestRateReductionMember 2019-01-01 2019-03-31 0000719220 us-gaap:ResidentialMortgageMember stba:BankruptcyMember 2019-01-01 2019-03-31 0000719220 us-gaap:NonperformingFinancingReceivableMember stba:BusinessBankingMember 2020-01-01 2020-03-31 0000719220 us-gaap:FinanceReceivablesMember us-gaap:CommercialRealEstateMember 2020-01-01 2020-03-31 0000719220 us-gaap:PerformingFinancingReceivableMember stba:BusinessBankingMember 2020-01-01 2020-03-31 0000719220 us-gaap:FinanceReceivablesMember stba:CommercialAndIndustrialMember 2020-01-01 2020-03-31 0000719220 us-gaap:PerformingFinancingReceivableMember 2020-01-01 2020-03-31 0000719220 us-gaap:NonperformingFinancingReceivableMember 2020-01-01 2020-03-31 0000719220 us-gaap:PerformingFinancingReceivableMember stba:ConsumerRealEstateMember 2020-01-01 2020-03-31 0000719220 us-gaap:PerformingFinancingReceivableMember stba:OtherConsumerMember 2020-01-01 2020-03-31 0000719220 us-gaap:PerformingFinancingReceivableMember stba:CommercialAndIndustrialMember 2020-01-01 2020-03-31 0000719220 us-gaap:NonperformingFinancingReceivableMember stba:CommercialAndIndustrialMember 2020-01-01 2020-03-31 0000719220 us-gaap:FinanceReceivablesMember 2020-01-01 2020-03-31 0000719220 us-gaap:FinanceReceivablesMember stba:ConsumerRealEstateMember 2020-01-01 2020-03-31 0000719220 us-gaap:PerformingFinancingReceivableMember us-gaap:CommercialRealEstateMember 2020-01-01 2020-03-31 0000719220 us-gaap:FinanceReceivablesMember stba:OtherConsumerMember 2020-01-01 2020-03-31 0000719220 us-gaap:PerformingFinancingReceivableMember us-gaap:ConstructionLoansMember 2020-01-01 2020-03-31 0000719220 us-gaap:NonperformingFinancingReceivableMember us-gaap:ConstructionLoansMember 2020-01-01 2020-03-31 0000719220 us-gaap:NonperformingFinancingReceivableMember us-gaap:CommercialRealEstateMember 2020-01-01 2020-03-31 0000719220 us-gaap:FinanceReceivablesMember stba:BusinessBankingMember 2020-01-01 2020-03-31 0000719220 us-gaap:FinanceReceivablesMember us-gaap:ConstructionLoansMember 2020-01-01 2020-03-31 0000719220 us-gaap:NonperformingFinancingReceivableMember stba:OtherConsumerMember 2020-01-01 2020-03-31 0000719220 us-gaap:NonperformingFinancingReceivableMember stba:ConsumerRealEstateMember 2020-01-01 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialRealEstateAndCommercialConstructionMember 2020-01-01 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialRealEstateAndCommercialConstructionMember 2019-12-31 0000719220 stba:PerformingFinancialInstrumentConvertedToNonperformingMember us-gaap:CommercialRealEstateMember 2020-01-01 2020-03-31 0000719220 2019-12-31 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialRealEstateAndCommercialConstructionMember 2020-03-31 0000719220 2020-03-31 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember 2019-12-31 0000719220 us-gaap:NonperformingFinancingReceivableMember us-gaap:ResidentialMortgageMember 2019-01-01 2019-12-31 0000719220 us-gaap:NonperformingFinancingReceivableMember stba:CommercialAndIndustrialMember 2019-01-01 2019-12-31 0000719220 us-gaap:PerformingFinancingReceivableMember us-gaap:CommercialRealEstateMember 2019-01-01 2019-12-31 0000719220 us-gaap:PerformingFinancingReceivableMember us-gaap:ConstructionLoansMember 2019-01-01 2019-12-31 0000719220 us-gaap:FinanceReceivablesMember stba:CommercialAndIndustrialMember 2019-01-01 2019-12-31 0000719220 us-gaap:PerformingFinancingReceivableMember 2019-01-01 2019-12-31 0000719220 us-gaap:FinanceReceivablesMember us-gaap:HomeEquityLoanMember 2019-01-01 2019-12-31 0000719220 us-gaap:FinanceReceivablesMember us-gaap:ResidentialMortgageMember 2019-01-01 2019-12-31 0000719220 us-gaap:FinanceReceivablesMember stba:InstallmentAndOtherConsumerMember 2019-01-01 2019-12-31 0000719220 us-gaap:NonperformingFinancingReceivableMember us-gaap:HomeEquityLoanMember 2019-01-01 2019-12-31 0000719220 us-gaap:FinanceReceivablesMember us-gaap:CommercialRealEstateMember 2019-01-01 2019-12-31 0000719220 us-gaap:FinanceReceivablesMember us-gaap:ConstructionLoansMember 2019-01-01 2019-12-31 0000719220 us-gaap:PerformingFinancingReceivableMember us-gaap:ResidentialMortgageMember 2019-01-01 2019-12-31 0000719220 us-gaap:NonperformingFinancingReceivableMember us-gaap:CommercialRealEstateMember 2019-01-01 2019-12-31 0000719220 us-gaap:PerformingFinancingReceivableMember stba:InstallmentAndOtherConsumerMember 2019-01-01 2019-12-31 0000719220 us-gaap:NonperformingFinancingReceivableMember stba:InstallmentAndOtherConsumerMember 2019-01-01 2019-12-31 0000719220 us-gaap:PerformingFinancingReceivableMember us-gaap:HomeEquityLoanMember 2019-01-01 2019-12-31 0000719220 us-gaap:NonperformingFinancingReceivableMember 2019-01-01 2019-12-31 0000719220 us-gaap:NonperformingFinancingReceivableMember us-gaap:ConstructionLoansMember 2019-01-01 2019-12-31 0000719220 us-gaap:FinanceReceivablesMember 2019-01-01 2019-12-31 0000719220 us-gaap:PerformingFinancingReceivableMember stba:CommercialAndIndustrialMember 2019-01-01 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialRealEstateIncludingBusinessBankingMember 2020-03-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:InstallmentAndOtherConsumerMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:ConstructionLoansIncludingBusinessBankingMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerConstructionMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialIncludingBusinessBankingMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:InstallmentAndOtherConsumerMember 2020-03-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember 2020-03-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerConstructionMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:ConstructionLoansIncludingBusinessBankingMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialIncludingBusinessBankingMember 2020-03-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialRealEstateIncludingBusinessBankingMember 2019-12-31 0000719220 stba:ConsumerRealEstateMember 2020-01-01 2020-03-31 0000719220 stba:CommercialAndIndustrialMember stba:PaymentDeferralAndExtendedMaturityMember 2020-01-01 2020-03-31 0000719220 us-gaap:ExtendedMaturityMember 2020-01-01 2020-03-31 0000719220 us-gaap:CommercialRealEstateMember stba:PaymentDeferralAndExtendedMaturityMember 2020-01-01 2020-03-31 0000719220 us-gaap:CommercialRealEstateMember 2020-01-01 2020-03-31 0000719220 stba:MaturityDateExtensionAndPaymentReductionMember 2020-01-01 2020-03-31 0000719220 stba:ConsumerRealEstateMember stba:MaturityDateExtensionAndPaymentReductionMember 2020-01-01 2020-03-31 0000719220 stba:CommercialAndIndustrialMember 2020-01-01 2020-03-31 0000719220 stba:ConsumerRealEstateMember stba:BankruptcyMember 2020-01-01 2020-03-31 0000719220 stba:PaymentDeferralAndExtendedMaturityMember 2020-01-01 2020-03-31 0000719220 stba:BankruptcyMember 2020-01-01 2020-03-31 0000719220 us-gaap:ConstructionLoansMember 2020-01-01 2020-03-31 0000719220 us-gaap:ConstructionLoansMember us-gaap:ExtendedMaturityMember 2020-01-01 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialRealEstateAndCommercialConstructionMember 2019-01-01 2019-12-31 0000719220 stba:ConsumerRealEstateMember 2019-01-01 2019-03-31 0000719220 us-gaap:CommercialRealEstateMember 2019-01-01 2019-03-31 0000719220 stba:ConsumerRealEstateMember 2018-12-31 0000719220 stba:OtherConsumerMember 2019-01-01 2019-03-31 0000719220 us-gaap:ConstructionLoansMember 2019-01-01 2019-03-31 0000719220 us-gaap:ConstructionLoansMember 2019-03-31 0000719220 stba:OtherConsumerMember 2018-12-31 0000719220 us-gaap:CommercialRealEstateMember 2018-12-31 0000719220 us-gaap:ConstructionLoansMember 2018-12-31 0000719220 us-gaap:CommercialRealEstateMember 2019-03-31 0000719220 stba:ConsumerRealEstateMember 2019-03-31 0000719220 stba:OtherConsumerMember 2019-03-31 0000719220 stba:CommercialAndIndustrialMember 2018-12-31 0000719220 stba:CommercialAndIndustrialMember 2019-03-31 0000719220 stba:ConsumerRealEstateMember 2019-12-31 0000719220 stba:OtherConsumerMember 2019-12-31 0000719220 stba:CommercialAndIndustrialMember 2019-12-31 0000719220 us-gaap:CommercialRealEstateMember 2019-12-31 0000719220 us-gaap:ConstructionLoansMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerConstructionMember us-gaap:PerformingFinancingReceivableMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:InstallmentAndOtherConsumerMember us-gaap:PerformingFinancingReceivableMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerConstructionMember us-gaap:NonperformingFinancingReceivableMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:InstallmentAndOtherConsumerMember us-gaap:NonperformingFinancingReceivableMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember us-gaap:NonperformingFinancingReceivableMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:PerformingFinancingReceivableMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember us-gaap:PerformingFinancingReceivableMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:NonperformingFinancingReceivableMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember us-gaap:ResidentialMortgageMember us-gaap:PerformingFinancingReceivableMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember us-gaap:HomeEquityLoanMember us-gaap:NonperformingFinancingReceivableMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2020-03-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerRealEstateMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2020-03-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:OtherConsumerMember 2020-03-31 0000719220 us-gaap:FinancingReceivables30To59DaysPastDueMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2020-03-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerRealEstateMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember 2020-03-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:OtherConsumerMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2020-03-31 0000719220 us-gaap:FinancingReceivables60To89DaysPastDueMember 2020-03-31 0000719220 us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2020-03-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerRealEstateMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2020-03-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:OtherConsumerMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2020-03-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:OtherConsumerMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2020-03-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerRealEstateMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember 2020-01-01 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember 2020-01-01 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember 2020-01-01 2020-03-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerRealEstateMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerRealEstateMember 2020-01-01 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember 2020-01-01 2020-03-31 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember 2019-12-31 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember 2019-12-31 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:OtherConsumerMember 2020-01-01 2020-03-31 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember 2019-12-31 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember 2019-12-31 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember us-gaap:ConsumerPortfolioSegmentMember stba:OtherConsumerMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:OtherConsumerMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember 2019-12-31 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustmentMember us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerRealEstateMember 2019-12-31 0000719220 us-gaap:NonperformingFinancingReceivableMember stba:CommercialAndIndustrialMember 2020-03-31 0000719220 us-gaap:CommercialRealEstateMember 2020-03-31 0000719220 us-gaap:PerformingFinancingReceivableMember stba:CommercialAndIndustrialMember 2020-03-31 0000719220 us-gaap:NonperformingFinancingReceivableMember us-gaap:CommercialRealEstateMember 2020-03-31 0000719220 stba:BusinessBankingMember 2020-03-31 0000719220 us-gaap:PerformingFinancingReceivableMember stba:OtherConsumerMember 2020-03-31 0000719220 us-gaap:NonperformingFinancingReceivableMember stba:OtherConsumerMember 2020-03-31 0000719220 us-gaap:NonperformingFinancingReceivableMember us-gaap:ConstructionLoansMember 2020-03-31 0000719220 stba:ConsumerRealEstateMember 2020-03-31 0000719220 us-gaap:ConstructionLoansMember 2020-03-31 0000719220 us-gaap:PerformingFinancingReceivableMember stba:ConsumerRealEstateMember 2020-03-31 0000719220 stba:CommercialAndIndustrialMember 2020-03-31 0000719220 stba:OtherConsumerMember 2020-03-31 0000719220 us-gaap:NonperformingFinancingReceivableMember 2020-03-31 0000719220 us-gaap:PerformingFinancingReceivableMember us-gaap:ConstructionLoansMember 2020-03-31 0000719220 us-gaap:PerformingFinancingReceivableMember 2020-03-31 0000719220 us-gaap:NonperformingFinancingReceivableMember stba:BusinessBankingMember 2020-03-31 0000719220 us-gaap:NonperformingFinancingReceivableMember stba:ConsumerRealEstateMember 2020-03-31 0000719220 us-gaap:PerformingFinancingReceivableMember stba:BusinessBankingMember 2020-03-31 0000719220 us-gaap:PerformingFinancingReceivableMember us-gaap:CommercialRealEstateMember 2020-03-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:OtherConsumerMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerRealEstateMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:OtherConsumerMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:OtherConsumerMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-12-31 0000719220 us-gaap:FinancingReceivables30To59DaysPastDueMember 2019-12-31 0000719220 us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerRealEstateMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2019-12-31 0000719220 us-gaap:ConsumerPortfolioSegmentMember stba:ConsumerRealEstateMember us-gaap:FinancingReceivablesEqualToGreaterThan90DaysPastDueMember 2019-12-31 0000719220 us-gaap:FinancingReceivables60To89DaysPastDueMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:FinancingReceivables60To89DaysPastDueMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember us-gaap:FinancingReceivables30To59DaysPastDueMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:SpecialMentionMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:PassMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:SubstandardMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember us-gaap:PassMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember us-gaap:SpecialMentionMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember us-gaap:PassMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember us-gaap:SpecialMentionMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember us-gaap:DoubtfulMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:DoubtfulMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:SpecialMentionMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:PassMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember us-gaap:SubstandardMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:SubstandardMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember us-gaap:SubstandardMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember us-gaap:DoubtfulMember 2019-12-31 0000719220 us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember us-gaap:DoubtfulMember 2019-12-31 0000719220 stba:CommercialAndIndustrialIncludingBusinessBankingMember 2019-12-31 0000719220 stba:ConsumerRealEstateIncludingBusinessBankingMember 2019-12-31 0000719220 stba:ConstructionLoansIncludingBusinessBankingMember 2019-12-31 0000719220 stba:CommercialRealEstateIncludingBusinessBankingMember 2019-12-31 0000719220 stba:OtherConsumerIncludingBusinessBankingMember 2019-12-31 0000719220 us-gaap:RealEstateMember us-gaap:CommercialPortfolioSegmentMember stba:OtherConsumerMember 2020-03-31 0000719220 stba:BlanketLienMember us-gaap:CommercialPortfolioSegmentMember stba:OtherConsumerMember 2020-03-31 0000719220 us-gaap:RealEstateMember us-gaap:CommercialPortfolioSegmentMember stba:ConsumerRealEstateMember 2020-03-31 0000719220 stba:OtherCollateralMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember 2020-03-31 0000719220 stba:InvestmentAndCashCollateralMember us-gaap:CommercialPortfolioSegmentMember stba:OtherConsumerMember 2020-03-31 0000719220 stba:OtherCollateralMember us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember 2020-03-31 0000719220 stba:BlanketLienMember us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember 2020-03-31 0000719220 stba:BlanketLienMember us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember 2020-03-31 0000719220 us-gaap:RealEstateMember 2020-03-31 0000719220 stba:BlanketLienMember us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember 2020-03-31 0000719220 us-gaap:RealEstateMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember 2020-03-31 0000719220 stba:InvestmentAndCashCollateralMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember 2020-03-31 0000719220 stba:OtherCollateralMember 2020-03-31 0000719220 stba:InvestmentAndCashCollateralMember us-gaap:CommercialPortfolioSegmentMember stba:ConsumerRealEstateMember 2020-03-31 0000719220 stba:OtherCollateralMember us-gaap:CommercialPortfolioSegmentMember stba:ConsumerRealEstateMember 2020-03-31 0000719220 us-gaap:RealEstateMember us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember 2020-03-31 0000719220 stba:InvestmentAndCashCollateralMember us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember 2020-03-31 0000719220 stba:BlanketLienMember us-gaap:CommercialPortfolioSegmentMember us-gaap:ConstructionLoansMember 2020-03-31 0000719220 stba:OtherCollateralMember us-gaap:CommercialPortfolioSegmentMember stba:OtherConsumerMember 2020-03-31 0000719220 stba:InvestmentAndCashCollateralMember us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember 2020-03-31 0000719220 stba:InvestmentAndCashCollateralMember us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember 2020-03-31 0000719220 stba:OtherCollateralMember us-gaap:CommercialPortfolioSegmentMember us-gaap:CommercialRealEstateMember 2020-03-31 0000719220 stba:OtherCollateralMember us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember 2020-03-31 0000719220 stba:BlanketLienMember us-gaap:CommercialPortfolioSegmentMember stba:ConsumerRealEstateMember 2020-03-31 0000719220 stba:InvestmentAndCashCollateralMember 2020-03-31 0000719220 us-gaap:RealEstateMember us-gaap:CommercialPortfolioSegmentMember stba:CommercialAndIndustrialMember 2020-03-31 0000719220 us-gaap:RealEstateMember us-gaap:CommercialPortfolioSegmentMember stba:BusinessBankingMember 2020-03-31 0000719220 stba:BlanketLienMember 2020-03-31 0000719220 stba:OtherConsumerMember us-gaap:PassMember 2020-03-31 0000719220 stba:OtherConsumerMember us-gaap:SubstandardMember 2020-03-31 0000719220 us-gaap:ConstructionLoansMember us-gaap:SubstandardMember 2020-03-31 0000719220 stba:OtherConsumerMember us-gaap:SpecialMentionMember 2020-03-31 0000719220 us-gaap:CommercialRealEstateMember us-gaap:SpecialMentionMember 2020-03-31 0000719220 stba:CommercialAndIndustrialMember us-gaap:SubstandardMember 2020-03-31 0000719220 stba:ConsumerRealEstateMember us-gaap:SpecialMentionMember 2020-03-31 0000719220 us-gaap:ConstructionLoansMember us-gaap:PassMember 2020-03-31 0000719220 stba:BusinessBankingMember us-gaap:SpecialMentionMember 2020-03-31 0000719220 stba:BusinessBankingMember us-gaap:PassMember 2020-03-31 0000719220 stba:CommercialAndIndustrialMember us-gaap:SpecialMentionMember 2020-03-31 0000719220 stba:ConsumerRealEstateMember us-gaap:SubstandardMember 2020-03-31 0000719220 us-gaap:CommercialRealEstateMember us-gaap:SubstandardMember 2020-03-31 0000719220 us-gaap:ConstructionLoansMember us-gaap:SpecialMentionMember 2020-03-31 0000719220 stba:CommercialAndIndustrialMember us-gaap:PassMember 2020-03-31 0000719220 stba:BusinessBankingMember us-gaap:SubstandardMember 2020-03-31 0000719220 stba:ConsumerRealEstateMember us-gaap:PassMember 2020-03-31 0000719220 us-gaap:CommercialRealEstateMember us-gaap:PassMember 2020-03-31 0000719220 us-gaap:OtherAssetsMember us-gaap:NondesignatedMember 2019-12-31 0000719220 us-gaap:OtherLiabilitiesMember us-gaap:NondesignatedMember 2020-03-31 0000719220 us-gaap:OtherLiabilitiesMember us-gaap:NondesignatedMember 2019-12-31 0000719220 us-gaap:OtherAssetsMember us-gaap:NondesignatedMember 2020-03-31 0000719220 us-gaap:OtherAssetsMember us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2019-12-31 0000719220 us-gaap:OtherLiabilitiesMember us-gaap:InterestRateLockCommitmentsMember us-gaap:NondesignatedMember 2019-12-31 0000719220 us-gaap:OtherLiabilitiesMember us-gaap:ForwardContractsMember us-gaap:NondesignatedMember 2019-12-31 0000719220 us-gaap:OtherLiabilitiesMember us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2019-12-31 0000719220 us-gaap:OtherAssetsMember us-gaap:ForwardContractsMember us-gaap:NondesignatedMember 2019-12-31 0000719220 us-gaap:OtherAssetsMember us-gaap:ForwardContractsMember us-gaap:NondesignatedMember 2020-03-31 0000719220 us-gaap:OtherLiabilitiesMember us-gaap:InterestRateLockCommitmentsMember us-gaap:NondesignatedMember 2020-03-31 0000719220 us-gaap:OtherLiabilitiesMember us-gaap:ForwardContractsMember us-gaap:NondesignatedMember 2020-03-31 0000719220 us-gaap:OtherAssetsMember us-gaap:InterestRateLockCommitmentsMember us-gaap:NondesignatedMember 2019-12-31 0000719220 us-gaap:OtherAssetsMember us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2020-03-31 0000719220 us-gaap:OtherLiabilitiesMember us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2020-03-31 0000719220 us-gaap:OtherAssetsMember us-gaap:InterestRateLockCommitmentsMember us-gaap:NondesignatedMember 2020-03-31 0000719220 us-gaap:InterestRateLockCommitmentsMember us-gaap:NondesignatedMember 2020-01-01 2020-03-31 0000719220 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2019-01-01 2019-03-31 0000719220 us-gaap:InterestRateLockCommitmentsMember us-gaap:NondesignatedMember 2019-01-01 2019-03-31 0000719220 us-gaap:InterestRateSwapMember us-gaap:NondesignatedMember 2020-01-01 2020-03-31 0000719220 us-gaap:ForwardContractsMember us-gaap:NondesignatedMember 2020-01-01 2020-03-31 0000719220 us-gaap:NondesignatedMember 2020-01-01 2020-03-31 0000719220 us-gaap:NondesignatedMember 2019-01-01 2019-03-31 0000719220 us-gaap:ForwardContractsMember us-gaap:NondesignatedMember 2019-01-01 2019-03-31 0000719220 us-gaap:MortgageBackedSecuritiesMember 2019-12-31 0000719220 us-gaap:FederalHomeLoanBankAdvancesMember 2020-03-31 0000719220 us-gaap:FederalHomeLoanBankAdvancesMember 2019-12-31 0000719220 us-gaap:MortgageBackedSecuritiesMember 2020-03-31 0000719220 us-gaap:LongTermDebtMember 2020-03-31 0000719220 stba:OtherShortTermBorrowingsMember 2020-03-31 0000719220 us-gaap:JuniorSubordinatedDebtMember 2020-03-31 0000719220 us-gaap:LongTermDebtMember 2019-12-31 0000719220 us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2019-12-31 0000719220 us-gaap:SecuritiesSoldUnderAgreementsToRepurchaseMember 2020-03-31 0000719220 stba:OtherShortTermBorrowingsMember 2019-12-31 0000719220 us-gaap:JuniorSubordinatedDebtMember 2019-12-31 0000719220 us-gaap:StandbyLettersOfCreditMember 2019-01-01 2019-12-31 0000719220 us-gaap:CommitmentsToExtendCreditMember 2019-01-01 2019-12-31 0000719220 us-gaap:StandbyLettersOfCreditMember 2020-01-01 2020-03-31 0000719220 us-gaap:CommitmentsToExtendCreditMember 2020-01-01 2020-03-31 0000719220 2019-01-01 2019-12-31 0000719220 stba:CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember 2019-12-31 0000719220 us-gaap:DepositAccountMember us-gaap:TransferredAtPointInTimeMember 2019-01-01 2019-03-31 0000719220 us-gaap:DepositAccountMember us-gaap:TransferredAtPointInTimeMember 2020-01-01 2020-03-31 0000719220 stba:WealthManagementMember us-gaap:TransferredAtPointInTimeMember 2020-01-01 2020-03-31 0000719220 us-gaap:CreditAndDebitCardMember us-gaap:TransferredAtPointInTimeMember 2019-01-01 2019-03-31 0000719220 us-gaap:CreditAndDebitCardMember us-gaap:TransferredOverTimeMember 2020-01-01 2020-03-31 0000719220 stba:WealthManagementMember us-gaap:TransferredOverTimeMember 2020-01-01 2020-03-31 0000719220 us-gaap:DepositAccountMember us-gaap:TransferredOverTimeMember 2020-01-01 2020-03-31 0000719220 us-gaap:DepositAccountMember us-gaap:TransferredOverTimeMember 2019-01-01 2019-03-31 0000719220 stba:WealthManagementMember us-gaap:TransferredOverTimeMember 2019-01-01 2019-03-31 0000719220 stba:OtherFeeRevenueMember us-gaap:TransferredAtPointInTimeMember 2019-01-01 2019-03-31 0000719220 us-gaap:CreditAndDebitCardMember us-gaap:TransferredAtPointInTimeMember 2020-01-01 2020-03-31 0000719220 stba:OtherFeeRevenueMember us-gaap:TransferredAtPointInTimeMember 2020-01-01 2020-03-31 0000719220 stba:WealthManagementMember us-gaap:TransferredAtPointInTimeMember 2019-01-01 2019-03-31 0000719220 us-gaap:CreditAndDebitCardMember us-gaap:TransferredOverTimeMember 2019-01-01 2019-03-31 0000719220 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember 2019-01-01 2019-03-31 0000719220 us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember 2020-01-01 2020-03-31 0000719220 us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember 2019-01-01 2019-03-31 0000719220 us-gaap:AccumulatedDefinedBenefitPlansAdjustmentNetUnamortizedGainLossMember 2020-01-01 2020-03-31 0000719220 srt:MaximumMember us-gaap:DefinedBenefitPlanEquitySecuritiesMember 2020-03-31 0000719220 srt:MinimumMember us-gaap:DefinedBenefitPlanEquitySecuritiesMember 2020-03-31 0000719220 srt:MaximumMember us-gaap:FixedIncomeFundsMember 2020-03-31 0000719220 srt:MinimumMember us-gaap:FixedIncomeFundsMember 2020-03-31 0000719220 stba:NewQualifiedAffordableHousingProjectMember 2020-03-31 0000719220 srt:ScenarioForecastMember stba:NewQualifiedAffordableHousingProjectMember 2020-01-01 2020-12-31 0000719220 stba:NewQualifiedAffordableHousingProjectMember 2019-09-11 0000719220 stba:NoninterestExpenseMember 2020-01-01 2020-03-31 0000719220 stba:NoninterestExpenseMember 2019-01-01 2019-03-31 0000719220 stba:NewShareRepurchasePlanMember 2019-09-16 0000719220 stba:NewShareRepurchasePlanMember 2020-01-01 2020-03-31 0000719220 stba:CoronavirusAidReliefAndEconomicSecurityActPaycheckProtectionProgramLoanMember us-gaap:SubsequentEventMember 2020-05-05 iso4217:USD iso4217:USD xbrli:shares xbrli:pure xbrli:shares stba:banking_location stba:note stba:security stba:loan

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
______________________________________
FORM 10-Q
______________________________________
(Mark One)

☒ | QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended March 31, 2020
OR

☐ | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from to
Commission file number 0-12508
______________________________________
S&T BANCORP INC
(Exact name of registrant as specified in its charter)
______________________________________

Pennsylvania |  |  |  | 25-1434426
(State or other jurisdiction of incorporation or organization) |  | (IRS Employer Identification No.)
800 Philadelphia Street | Indiana | PA |  | 15701
(Address of principal executive offices) |  | (zip code)

800-325-2265
(Registrant’s telephone number, including area code)
Not Applicable
(Former name, former address, and former fiscal year, if changed since last report)
Securities registered pursuant to Section 12(b) of the Act:

Title of each class | Trading Symbol(s) | Name of each exchange on which registered
Common Stock, $2.50 par value | STBA | The NASDAQ Stock Market LLC

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐
Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and "emerging growth company" in Rule 12b-2 of the Exchange Act.

Large accelerated filer | ☒ | Accelerated filer | ☐
Non-accelerated filer | ☐ | Smaller reporting company | ☐
|  | Emerging growth company | ☐
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒
APPLICABLE ONLY TO CORPORATE ISSUERS:
Indicate the number of shares outstanding of each of the issuer’s classes of common stock, as of the latest practical date.
Common Stock, $2.50 Par Value - 39,242,510 shares as of May 8, 2020

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
INDEX
S&T BANCORP, INC. AND SUBSIDIARIES

|  | Page No.
PART I. FINANCIAL INFORMATION |
Item 1. | Financial Statements |
| Consolidated Balance Sheets - March 31, 2020 and December 31, 2019 | 2
| Consolidated Statements of Comprehensive Income - Three Months Ended March 31, 2020 and 2019 | 3
| Consolidated Statements of Changes in Shareholders' Equity - Three Months Ended March 31, 2020 and 2019 | 4
| Consolidated Statements of Cash Flows - Three Months Ended March 31, 2020 and 2019 | 5
| Notes to Consolidated Financial Statements | 6
Item 2. | Management's Discussion and Analysis of Financial Condition and Results of Operations | 43
Item 3. | Quantitative and Qualitative Disclosures About Market Risk | 59
Item 4. | Controls and Procedures | 60
PART II. OTHER INFORMATION |
Item 1. | Legal Proceedings | 61
Item 1A. | Risk Factors | 61
Item 2. | Unregistered Sales of Equity Securities and Use of Proceeds | 62
Item 3. | Defaults Upon Senior Securities | 62
Item 4. | Mine Safety Disclosures | 62
Item 5. | Other Information | 62
Item 6. | Exhibits | 62
| Signatures | 63

1

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
CONSOLIDATED BALANCE SHEETS
(Unaudited)

| March 31, 2020 |  | December 31, 2019
(dollars in thousands, except per share data) | (Unaudited) |  | (Audited)
ASSETS |  |  |  |  |
Cash and due from banks, including interest-bearing deposits of $113,505 and $124,491 at March 31, 2020 and December 31, 2019 |  | $ | 187,684 |  |  |  | $ | 197,823 |
Securities, at fair value |  | 799,532 |  |  |  | 784,283 |
Loans held for sale |  | 7,309 |  |  |  | 5,256 |
Portfolio loans, net of unearned income |  | 7,246,745 |  |  |  | 7,137,152 |
Allowance for credit losses on loans |  | (96,850 | ) |  |  | (62,224 | )
Portfolio loans, net |  | 7,149,895 |  |  |  | 7,074,928 |
Bank owned life insurance |  | 80,978 |  |  |  | 80,473 |
Premises and equipment, net |  | 56,659 |  |  |  | 56,940 |
Federal Home Loan Bank and other restricted stock, at cost |  | 28,253 |  |  |  | 22,977 |
Goodwill |  | 374,270 |  |  |  | 371,621 |
Other intangible assets, net |  | 10,287 |  |  |  | 10,919 |
Other assets |  | 310,629 |  |  |  | 159,429 |
Total Assets |  | $ | 9,005,496 |  |  |  | $ | 8,764,649 |
LIABILITIES |  |  |  |  |
Deposits: |  |  |  |  |
Noninterest-bearing demand |  | $ | 1,702,960 |  |  |  | $ | 1,698,082 |
Interest-bearing demand |  | 962,937 |  |  |  | 962,331 |
Money market |  | 1,967,692 |  |  |  | 1,949,811 |
Savings |  | 836,237 |  |  |  | 830,919 |
Certificates of deposit |  | 1,588,053 |  |  |  | 1,595,433 |
Total Deposits |  | 7,057,879 |  |  |  | 7,036,576 |
Securities sold under repurchase agreements |  | 69,644 |  |  |  | 19,888 |
Short-term borrowings |  | 410,240 |  |  |  | 281,319 |
Long-term borrowings |  | 50,180 |  |  |  | 50,868 |
Junior subordinated debt securities |  | 64,038 |  |  |  | 64,277 |
Other liabilities |  | 177,264 |  |  |  | 119,723 |
Total Liabilities |  | 7,829,245 |  |  |  | 7,572,651 |
SHAREHOLDERS’ EQUITY |  |  |  |  |
Common stock ($2.50 par value) Authorized—50,000,000 shares Issued—41,449,444 shares at March 31, 2020 and December 31, 2019 Outstanding— 39,125,425 shares at March 31, 2020 and 39,560,304 shares at December 31, 2019 |  | 103,623 |  |  |  | 103,623 |
Additional paid-in capital |  | 400,387 |  |  |  | 399,944 |
Retained earnings |  | 740,726 |  |  |  | 761,083 |
Accumulated other comprehensive loss |  | 5,672 |  |  |  | (11,670 | )
Treasury stock (2,324,019 shares at March 31, 2020 and 1,889,140 shares at December 31, 2019, at cost) |  | (74,157 | ) |  |  | (60,982 | )
Total Shareholders’ Equity |  | 1,176,251 |  |  |  | 1,191,998 |
Total Liabilities and Shareholders’ Equity |  | $ | 9,005,496 |  |  |  | $ | 8,764,649 |

See Notes to Consolidated Financial Statements
2

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
(Unaudited)

| Three Months Ended March 31,
(dollars in thousands, except per share data) | 2020 |  | 2019
INTEREST AND DIVIDEND INCOME |  |  |  |  |
Loans, including fees |  | $ | 82,051 |  |  |  | $ | 73,392 |
Investment Securities: |  |  |  |  |
Taxable |  | 4,215 |  |  |  | 3,790 |
Tax-exempt |  | 870 |  |  |  | 844 |
Dividends |  | 453 |  |  |  | 564 |
Total Interest and Dividend Income |  | 87,589 |  |  |  | 78,590 |
INTEREST EXPENSE |  |  |  |  |
Deposits |  | 15,338 |  |  |  | 14,981 |
Borrowings and junior subordinated debt securities |  | 2,215 |  |  |  | 3,253 |
Total Interest Expense |  | 17,553 |  |  |  | 18,234 |
NET INTEREST INCOME |  | 70,036 |  |  |  | 60,356 |
Provision for credit losses |  | 20,050 |  |  |  | 5,684 |
Net Interest Income After Provision for Credit Losses |  | 49,986 |  |  |  | 54,672 |
NONINTEREST INCOME |  |  |  |  |
Net gain on sale of securities |  | — |  |  |  | — |
Service charges on deposit accounts |  | 3,558 |  |  |  | 3,153 |
Debit and credit card |  | 3,482 |  |  |  | 2,974 |
Commercial loan swap income |  | 2,484 |  |  |  | 581 |
Wealth management |  | 2,362 |  |  |  | 2,048 |
Mortgage banking |  | 1,236 |  |  |  | 494 |
Other |  | (719 | ) |  |  | 2,112 |
Total Noninterest Income |  | 12,403 |  |  |  | 11,362 |
NONINTEREST EXPENSE |  |  |  |  |
Salaries and employee benefits |  | 21,335 |  |  |  | 20,910 |
Data processing and information technology |  | 3,868 |  |  |  | 3,233 |
Net occupancy |  | 3,765 |  |  |  | 3,036 |
Furniture, equipment and software |  | 2,519 |  |  |  | 2,230 |
Merger related expenses |  | 2,342 |  |  |  | — |
Other taxes |  | 1,600 |  |  |  | 1,185 |
Marketing |  | 1,111 |  |  |  | 1,141 |
Professional services and legal |  | 1,048 |  |  |  | 1,184 |
FDIC insurance |  | 770 |  |  |  | 516 |
Other |  | 8,033 |  |  |  | 5,449 |
Total Noninterest Expense |  | 46,391 |  |  |  | 38,884 |
Income Before Taxes |  | 15,998 |  |  |  | 27,150 |
Provision for income taxes |  | 2,767 |  |  |  | 4,222 |
Net Income |  | $ | 13,231 |  |  |  | $ | 22,928 |
Earnings per share—basic |  | $ | 0.34 |  |  |  | $ | 0.67 |
Earnings per share—diluted |  | $ | 0.34 |  |  |  | $ | 0.66 |
Dividends declared per share |  | $ | 0.28 |  |  |  | $ | 0.27 |
Comprehensive Income |  | $ | 30,573 |  |  |  | $ | 29,104 |

See Notes to Consolidated Financial Statements
3

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY
(Unaudited)

| For the three months ended March 31, 2019
(dollars in thousands, except share and per share data) | Common Stock |  | Additional Paid-in Capital |  | Retained Earnings |  | Accumulated Other Comprehensive (Loss)/Income |  | Treasury Stock |  | Total
Balance at January 1, 2019 |  | $ | 90,326 |  |  |  | $ | 210,345 |  |  |  | $ | 701,819 |  |  |  | $ | (23,107 | ) |  |  | $ | (43,622 | ) |  |  | $ | 935,761 |
Net income for the three months ended March 31, 2019 |  | — |  |  |  | — |  |  |  | 22,928 |  |  |  | — |  |  |  | — |  |  |  | 22,928 |
Other comprehensive income (loss), net of tax |  | — |  |  |  | — |  |  |  | — |  |  |  | 6,176 |  |  |  | — |  |  |  | 6,176 |
Adoption of accounting standard - Leases |  | — |  |  |  | — |  |  |  | 167 |  |  |  | — |  |  |  | — |  |  |  | 167 |
Cash dividends declared ($0.27 per share) |  | — |  |  |  | — |  |  |  | (9,317 | ) |  |  | — |  |  |  | — |  |  |  | (9,317 | )
Treasury stock issued for restricted stock awards (0 shares, net of forfeitures of 39,834 shares) |  | — |  |  |  | — |  |  |  | 481 |  |  |  | — |  |  |  | (1,357 | ) |  |  | (876 | )
Repurchase of S&T Stock (313,904 shares) |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (12,287 | ) |  |  | (12,287 | )
Recognition of restricted stock compensation expense |  | — |  |  |  | 604 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 604 |
Balance at March 31, 2019 |  | $ | 90,326 |  |  |  | $ | 210,949 |  |  |  | $ | 716,078 |  |  |  | $ | (16,931 | ) |  |  | $ | (57,266 | ) |  |  | $ | 943,156 |
| For the three months ended March 31, 2020
(dollars in thousands, except share and per share data) | Common Stock |  | Additional Paid-in Capital |  | Retained Earnings |  | Accumulated Other Comprehensive (Loss)/Income |  | Treasury Stock |  | Total
Balance at January 1, 2020 |  | $ | 103,623 |  |  |  | $ | 399,944 |  |  |  | $ | 761,083 |  |  |  | $ | (11,670 | ) |  |  | $ | (60,982 | ) |  |  | $ | 1,191,998 |
Net income for the three months ended March 31, 2020 |  | — |  |  |  | — |  |  |  | 13,231 |  |  |  | — |  |  |  | — |  |  |  | 13,231 |
Other comprehensive income (loss), net of tax |  | — |  |  |  | — |  |  |  | — |  |  |  | 17,342 |  |  |  | — |  |  |  | 17,342 |
Adoption of accounting standard - credit losses |  | — |  |  |  | — |  |  |  | (22,590 | ) |  |  | — |  |  |  | — |  |  |  | (22,590 | )
Cash dividends declared ($0.28 per share) |  | — |  |  |  | — |  |  |  | (11,051 | ) |  |  | — |  |  |  | — |  |  |  | (11,051 | )
Treasury stock issued for restricted stock awards (3,290 shares, net of forfeitures of 26,739 shares) |  | — |  |  |  | — |  |  |  | 53 |  |  |  | — |  |  |  | (616 | ) |  |  | (563 | )
Repurchase of S&T Stock (411,430 shares) |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (12,559 | ) |  |  | (12,559 | )
Recognition of restricted stock compensation expense |  | — |  |  |  | 443 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 443 |
Balance at March 31, 2020 |  | $ | 103,623 |  |  |  | $ | 400,387 |  |  |  | $ | 740,726 |  |  |  | $ | 5,672 |  |  |  | $ | (74,157 | ) |  |  | $ | 1,176,251 |

See Notes to Consolidated Financial Statements
4

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
CONSOLIDATED STATEMENTS OF CASH FLOWS
(Unaudited)

| Three Months Ended March 31,
(dollars in thousands) |  | 2020 |  |  | 2019
OPERATING ACTIVITIES |  |  |  |  |
Net income |  | $ | 13,231 |  |  |  | $ | 22,928 |
Adjustments to reconcile net income to net cash provided by operating activities: |  |  |  |  |
Provision for credit losses |  | 20,050 |  |  |  | 5,649 |
Provision for unfunded loan commitments |  | — |  |  |  | 35 |
Net depreciation, amortization and accretion |  | 1,171 |  |  |  | 1,420 |
Net amortization of discounts and premiums on securities |  | 1,154 |  |  |  | 776 |
Stock-based compensation expense |  | 443 |  |  |  | 604 |
Gain on the sale of mortgage loans, net |  | (536 | ) |  |  | (293 | )
Mortgage loans originated for sale |  | (37,332 | ) |  |  | (14,506 | )
Proceeds from the sale of mortgage loans |  | 35,358 |  |  |  | 14,464 |
Net change in: |  |  |  |  |
Interest receivable |  | 26 |  |  |  | (1,963 | )
Interest payable |  | (242 | ) |  |  | (789 | )
Other assets |  | (149,186 | ) |  |  | (3,466 | )
Other liabilities |  | 55,902 |  |  |  | 5,600 |
Net Cash (Used in) Provided by Operating Activities |  | (59,961 | ) |  |  | 30,459 |
INVESTING ACTIVITIES |  |  |  |  |
Purchases of securities |  | (30,292 | ) |  |  | (9,437 | )
Proceeds from maturities, prepayments and calls of securities |  | 33,869 |  |  |  | 20,193 |
Net (purchases of) proceeds from sales of Federal Home Loan Bank stock |  | (5,277 | ) |  |  | 9,477 |
Net (increase) decrease in loans |  | (122,507 | ) |  |  | 4,760 |
Proceeds from sale of loans not originated for resale |  | — |  |  |  | 465 |
Purchases of premises and equipment |  | (1,429 | ) |  |  | (1,757 | )
Net Cash (Used in) Provided by Investing Activities |  | (125,636 | ) |  |  | 23,701 |
FINANCING ACTIVITIES |  |  |  |  |
Net increase in core deposits |  | 28,684 |  |  |  | 170,744 |
Net decrease in certificates of deposit |  | (7,042 | ) |  |  | (11,241 | )
Net increase in securities sold under repurchase agreements |  | 49,756 |  |  |  | 5,044 |
Net increase (decrease) in short-term borrowings |  | 128,921 |  |  |  | (235,000 | )
Proceeds from long-term borrowings |  | — |  |  |  | 104 |
Repayments on long-term borrowings |  | (688 | ) |  |  | — |
Treasury shares issued-net |  | (563 | ) |  |  | (876 | )
Cash dividends paid to common shareholders |  | (11,051 | ) |  |  | (9,317 | )
Repurchase of common stock |  | (12,559 | ) |  |  | (12,287 | )
Net Cash Provided by (Used in) Financing Activities |  | 175,458 |  |  |  | (92,829 | )
Net decrease in cash and cash equivalents |  | (10,139 | ) |  |  | (38,669 | )
Cash and cash equivalents at beginning of period |  | 197,823 |  |  |  | 155,489 |
Cash and Cash Equivalents at End of Period |  | $ | 187,684 |  |  |  | $ | 116,820 |
Supplemental Disclosures |  |  |  |  |
Leased right-of-use operating assets and lease liabilities added to the balance sheet |  | $ | 91 |  |  |  | $ | 35,686 |
Interest paid |  | $ | 17,795 |  |  |  | $ | 19,023 |
Income taxes paid, net of refunds |  | $ | 210 |  |  |  | $ | 1,432 |
Transfers of loans to other real estate owned |  | $ | 110 |  |  |  | $ | 80 |

See Notes to Consolidated Financial Statements
5

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
NOTE 1. BASIS OF PRESENTATION
Principles of Consolidation
The interim Consolidated Financial Statements include the accounts of S&T Bancorp, Inc., or S&T, and its wholly owned subsidiaries. All significant intercompany transactions have been eliminated in consolidation. Investments of 20 percent to 50 percent of the outstanding common stock of investees are accounted for using the equity method of accounting.
Basis of Presentation
The accompanying unaudited interim Consolidated Financial Statements of S&T have been prepared in accordance with generally accepted accounting principles, or GAAP, in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with the audited Consolidated Financial Statements included in our Annual Report on Form 10-K for the year ended December 31, 2019, filed with the Securities and Exchange Commission, or SEC, on March 2, 2020. In the opinion of management, the accompanying interim financial information reflects all adjustments, consisting of normal recurring adjustments, necessary to present fairly our financial position and the results of operations for each of the interim periods presented. Results of operations for interim periods are not necessarily indicative of the results of operations that may be expected for a full year or any future period.
On June 5, 2019 we entered into an agreement to acquire DNB Financial Corporation, or DNB, and the transaction was completed on November 30, 2019. Refer to Note 2, Business Combinations for further details on the merger.
Reclassification
A mounts in prior period financial statements and footnotes are reclassified whenever necessary to conform to the current period presentation. Reclassifications had no effect on our results of operations or financial condition.
Use of Estimates
The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates.
Recently Adopted Accounting Standards Updates, or ASU or Update
Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract
In August 2018, the Financial Accounting Standards Board, or FASB, issued ASU No. 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. The amendments in this ASU apply to an entity that is a customer in a hosting arrangement that is a service contract. These amendments relate to accounting for implementation costs (e.g., implementation, setup and other upfront costs). These amendments require an entity in a hosting arrangement that is a service contract to follow the guidance in Subtopic 350-40 to determine which costs to capitalize and which costs to expense. These amendments require the entity to expense the capitalized implementation costs of a hosting arrangement that is a service contract over the term of the hosting arrangement. This ASU is effective for annual and interim periods beginning after December 15, 2019. We adopted this ASU on January 1, 2020. The amendments in this ASU did not materially impact our Consolidated Balance Sheets or Consolidated Statements of Comprehensive Income.
Fair Value Measurement - Changes to the Disclosure Requirements for Fair Value Measurement
In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement - Changes to the Disclosure Requirements for Fair Value Measurement. The amendments in this ASU remove certain disclosures from Topic 820, modify disclosures and/or require additional disclosures. The amendments in this Update required us to change our Fair Value disclosures beginning with the disclosures included in this Form 10-Q for the period ended March 31, 2020. We adopted this ASU on January 1, 2020. The amendments in this ASU did not materially impact our Consolidated Balance Sheets or Consolidated Statements of Comprehensive Income. Refer to Note 4. Fair Value Measurements.
6

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 1. BASIS OF PRESENTATION - continued
Intangibles - Goodwill and Other - Simplifying the Test for Goodwill Impairment
In January 2017, the FASB issued ASU No. 2017-04, Intangibles - Goodwill and Other - Simplifying the Test for Goodwill Impairment (Topic 350). The main objective of this ASU is to simplify the current requirements for testing goodwill for impairment by eliminating step two from the goodwill impairment test. The amendments are expected to reduce the complexity and costs associated with performing the goodwill impairment test, which could result in recording impairment charges sooner. This Update is effective for any interim and annual impairment tests in reporting periods in fiscal years beginning after December 15, 2019. We adopted the amendments of this ASU on January 1, 2020. The amendments in this ASU did not have any impact on our Consolidated Balance Sheets or Consolidated Statements of Comprehensive Income.
Financial Instruments - Credit Losses
On January 1, 2020, we adopted ASU 2016-13 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which replaces the incurred loss methodology for determining our provision for credit losses, and allowance for credit losses, or ACL, with an expected loss methodology that is referred to as the Current Expected Credit Loss, or CECL, model. The measurement of expected credit losses under the CECL methodology is applicable to financial assets measured at amortized cost, including our loans and off-balance sheet credit exposures. In addition, ASU 2016-13 made changes to the accounting for available-for-sale debt securities. Credit losses related to available-for-sale debt securities (regardless of whether the impairment is considered to be other-than-temporary) will be measured in a manner similar to the present, except that such losses will be recorded as allowances rather than as reductions in the amortized cost of the related securities.
We adopted ASU 2016-13 using the modified retrospective method for all financial assets measured at amortized cost and off-balance sheet credit exposures. Results for reporting periods beginning after January 1, 2020 are presented under ASU 2016-13 while prior period amounts continue to be reported in accordance with previously applicable GAAP.
We made the accounting policy election to not measure an ACL for accrued interest receivables for loans and securities. Accrued interest deemed uncollectible will be written off through interest income.
The majority of our available-for-sale debt securities are government agency-backed securities for which the risk of loss is minimal, and accordingly the ACL is immaterial.
In connection with our adoption of ASU 2016-13, we made changes to our loan portfolio segments to align with the methodology applied in determining the allowance under CECL. Refer to Note 7 Allowance for Credit Losses for further discussion of these portfolio segments. Our new segmentation breaks out business banking loans from our other loan segments: Commercial Real Estate, or CRE, Commercial and Industrial, or C&I , Commercial Construction, Consumer Real Estate and Other Consumer. Business banking loans are commercial loans made to small businesses that are standard, non-complex products and evaluated through a streamlined credit approval process that has been designed to maximize efficiency while maintaining high credit quality standards.
7

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 1. BASIS OF PRESENTATION - continued
The following table details the impact of ASU 2016-13 and the reclassification of loans for the identification of new portfolio loan segments under CECL:

| January 1, 2020
(dollars in thousands) | As Reported Under ASU 2016-13 |  | Pre-ASU 2016-13 |  | Impact of ASU 2016-13 Adoption
Assets: |  |  |  |  |  |  |  |
Loans held for investment (outstanding balance) |  |  |  |  |  |  |  |
Commercial real estate |  | $ | 2,946,319 |  |  |  | $ | 3,416,518 |  |  |  | $ | (470,199 | )
Commercial and industrial |  | 1,458,541 |  |  |  | 1,720,833 |  |  |  | (262,292 | )
Commercial construction |  | 345,263 |  |  |  | 375,445 |  |  |  | (30,182 | )
Business banking |  | 1,092,908 |  |  |  | — |  |  |  | 1,092,908 |
Consumer real estate |  | 1,235,352 |  |  |  | 1,545,323 |  |  |  | (309,971 | )
Other consumer |  | 58,769 |  |  |  | 79,033 |  |  |  | (20,264 | )
Allowance for credit losses on loans |  | (89,577 | ) |  |  | (62,224 | ) |  |  | (27,353 | )
Total loans held for investment, net |  | $ | 7,047,575 |  |  |  | $ | 7,074,928 |  |  |  | $ | (27,353 | )
Net deferred tax asset |  | $ | 19,317 |  |  |  | $ | 13,206 |  |  |  | $ | 6,111 |
Liabilities: |  |  |  |  |  |  |  |
Allowance for credit losses on unfunded loan commitments |  | $ | 4,462 |  |  |  | $ | 3,113 |  |  |  | $ | 1,349 |
Equity: |  |  |  |  |  |  |  |
Retained earnings |  | $ | 738,493 |  |  |  | $ | 761,083 |  |  |  | $ | (22,590 | )

The adoption of ASU 2016-13 resulted in an increase to our ACL of $27.4 million on January 1, 2020. The increase included $8.2 million for S&T legacy loans and $9.3 million for acquired loans from the DNB merger. Under the previously applicable accounting guidance, a credit reserve was not recorded for acquired loans upon acquisition, however, ASU 2016-13 requires an ACL to be recognized for acquired loan similar to originated loans. We also recorded a day one adjustment of $9.9 million primarily related to a Commercial and Industrial, or C&I, relationship that was charged off in the first quarter of 2020. We obtained information on the relationship subsequent to filing our December 31, 2019 Form 10-K, but before the end of the first quarter of 2020. The updated information supported a loss existed at January 1, 2020. As of January 1, 2020, we recorded a cumulative-effect adjustment of $22.6 million to decrease retained earnings related to the adoption of ASU 2016-13.
Allowance for Credit Losses Policy
The ACL is a valuation reserve established and maintained by charges against operating income and is deducted from the amortized cost basis of loans to present the net amount expected to be collected on the loans. Loans, or portions thereof, are charged off against the ACL when they are deemed uncollectible. Expected recoveries do not exceed the aggregate of amounts previously charged-off and expected to be charged-off. The ACL is an estimate of expected credit losses, measured over the contractual life of a loan, that considers our historical loss experience, current conditions and forecasts of future economic conditions. Determination of an appropriate ACL is inherently subjective and may have significant changes from period to period.
The methodology for determining the ACL has two main components: evaluation of expected credit losses for certain groups of homogeneous loans that share similar risk characteristics and evaluation of loans that do not share risk characteristics with other loans.
The ACL for homogeneous loans is calculated using a life-time loss rate methodology with both a quantitative and a qualitative analysis that is applied on a quarterly basis. The ACL model is comprised of six distinct portfolio segments: 1) Construction, 2) Commercial Real Estate, or CRE, 3) C&I, 4) Business Banking, 5) Consumer Real Estate and 6) Other Consumer. Each segment has a distinct set of risk characteristics monitored by management. We further evaluate the ACL at a disaggregated level which includes type of collateral, loan participations, non-owner occupied and our internal risk rating system for the commercial segments and type of collateral, lien position, and FICO score, for the consumer segments. Historical credit loss experience is the basis for the estimation of expected credit losses. We apply historical loss rates to pools of loans with similar risk characteristics. After consideration of the historic loss calculation, management applies qualitative adjustments to reflect the current conditions and reasonable and supportable forecasts not already reflected in the historical loss information at the balance sheet date. Our reasonable and supportable forecast adjustment is based on the unemployment forecast and management judgment. For periods beyond our two year reasonable and supportable forecast, we revert to the historical loss rate. We revert to historical loss rates utilizing a straight-line method over a one year reversion period. The qualitative adjustments for current conditions are based upon changes in lending policies and practices, experience and ability of lending staff, quality of the bank’s loan review system, value of underlying
8

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 1. BASIS OF PRESENTATION - continued
collateral for collateral dependent loans, the existence of and changes in concentrations and other external factors. These modified historical loss rates are multiplied by the outstanding principal balance of each loan to calculate a required reserve. A similar process is employed to calculate a reserve assigned to off-balance sheet commitments, specifically unfunded loan commitments and letters of credit, and any needed reserve is recorded in other liabilities.
The ACL for individual loans begins with the use of normal credit review procedures to identify whether a loan no longer shares similar risk characteristics with other pooled loans and therefore, should be individually assessed. We evaluate all commercial loans greater than $0.5 million that meet the following criteria: 1) when it is determined that foreclosure is probable, 2) substandard, doubtful and nonperforming loans when repayment is expected to be provided substantially through the operation or sale of the collateral, 3) any commercial troubled debt restructuring, or TDR, or any loan reasonably expected to become a TDR whether on accrual or nonaccrual status and 4) when it is determined by management that a loan does not share similar risk characteristics with other loans. Specific reserves are established based on the following three acceptable methods for measuring the ACL: 1) the present value of expected future cash flows discounted at the loan’s original effective interest rate; 2) the loan’s observable market price; or 3) the fair value of the collateral when the loan is collateral dependent. Our individual loan evaluations consist primarily of the fair value of collateral method because most of our loans are collateral dependent. Collateral values are discounted to consider disposition costs when appropriate. A specific reserve is established or a charge-off is taken if the fair value of the loan is less than the loan balance.
Although we believe our process for determining the ACL appropriately considers all the factors that would likely result in credit losses, the process includes subjective elements and may be susceptible to significant change. To the extent actual losses are higher than management estimates, additional provision for credit losses could be required and could adversely affect our earnings or financial position in future periods.
Accounting Standards Issued But Not Yet Adopted
Compensation-Retirement Benefits-Defined Benefit Plans-General (Subtopic 715-20): Changes to the Disclosure Requirements for Defined Benefit Plans
In August 2018, the FASB issued ASU No. 2018-14, Compensation-Retirement Benefits-Defined Benefit Plans-General (Subtopic 715-20): Changes to the Disclosure Requirements for Defined Benefit Plans. The amendments in this ASU apply to all employers that sponsor defined benefit pension or other postretirement plans. These amendments remove certain disclosures from Topic 715-20 and require additional disclosures. The amendments in this ASU will require S&T to update our employee benefits disclosures beginning with our Form 10-Q for the period ended March 31, 2021. The amendments in this ASU will have no impact on our consolidated financial statements.
Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes
In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The amendments in this ASU simplifies the accounting for income taxes by removing certain exceptions and improves the consistent application of GAAP by clarifying and amending other existing guidance. The amendments in this ASU will be effective on January 1, 2021 and are not expected to have any impact on our consolidated financial statements.
Reference Rate Reform (Topic 848) Facilitation of the Effects of Reference Rate Reform on Financial Reporting
In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. The amendments in this ASU provide optional guidance for a limited period of time to ease the potential burden in accounting for or recognizing the effects of reference rate reform on financial reporting. The amendments provide optional expedients and exceptions for applying GAAP to loan and lease agreements, derivative contracts, and other transactions affected by the anticipated transition away from LIBOR toward new interest rate benchmarks. Modified contracts that meet certain scope guidance are eligible for relief from the modification accounting requirements in US GAAP. The optional guidance generally allows for the modified contract to be accounted for as a continuation of the existing contract and does not require contract remeasurement at the modification date or reassessment of a previous accounting determination. The amendments in this ASU are effective as of March 12, 2020 through December 31, 2022. We are evaluating the impacts of this ASU and have not yet determined whether LIBOR transition and this ASU will have material effects on our business operations and consolidated financial statements.
9

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 2. BUSINESS COMBINATIONS
On November 30, 2019, we completed our acquisition of DNB Financial Corporation, or DNB, and DNB First National Association, its wholly-owned bank subsidiary, located in Downingtown, Pennsylvania. The acquisition of DNB expanded our Eastern Pennsylvania market by adding 14 banking locations, in an all-stock transaction structured as a merger of DNB with and into S&T, with S&T being the surviving entity. The related systems conversion of DNB into S&T Bank occurred on February 7, 2020.
DNB shareholders received, without interest, 1.22 shares of S&T common stock for each share of DNB common stock. The total purchase price was approximately $201.0 million, which included $0.4 million of cash and 5,318,964 S&T common shares at a fair value of $37.72 per share. The fair value of $37.72 per share of S&T common stock was based on the November 30, 2019 closing price.
The Merger was accounted for under the acquisition method of accounting and our Consolidated Financial Statements include all DNB Bank transactions beginning on December 1, 2019. Goodwill of $86.0 million at March 31, 2020 was calculated as the excess of the consideration exchanged over the fair value of the identifiable net assets acquired. All of the goodwill was assigned to our Community Banking segment. The goodwill recognized is not deductible for tax purposes.
The following table provides a summary of the assets acquired and liabilities assumed by DNB, the preliminary estimates of the fair value adjustments necessary to adjust those acquired assets and assumed liabilities to estimated fair value and the preliminary estimates of the resultant fair values of those assets and liabilities by S&T at November 30, 2019, the acquisition date. Preliminary estimates were adjusted by $1.8 million during the three months ended March 31, 2020. These measurement period adjustments primarily related to $2.5 million reduction in the fair value of loans, $0.3 million reduction in the fair value of borrowings and $0.3 million in deferred taxes related to these valuation adjustments. Preliminary fair value adjustments continue to be evaluated by management and may be subject to further adjustment during the measurement period, which may not extend beyond one year following the acquisition.
The following table presents the preliminary fair value adjustments and the measurement period adjustments as of the dates presented:

| November 30, 2019 |  | March 31, 2020
| As Recorded by DNB |  | Preliminary Fair Value Adjustments(1) |  | As Recorded by S&T |  | Measurement Period Adjustments |  | As Recorded by S&T
Fair Value of Assets Acquired |  |  |  |  |  |  |  |  |
Cash and cash equivalents | $ | 64,119 |  |  | $ | — |  |  | $ | 64,119 |  |  | $ | — |  |  | $ | 64,119 |
Securities and other investments | 108,715 |  |  | 183 |  |  | 108,898 |  |  | — |  |  | 108,898 |
Loans | 917,127 |  |  | (8,143 | ) |  | 908,984 |  |  | (2,496 | ) |  | 906,488 |
Allowance for credit losses | (6,487 | ) |  | 6,487 |  |  | — |  |  | — |  |  | — |
Goodwill | 15,525 |  |  | (15,525 | ) |  | — |  |  | — |  |  | — |
Premises and equipment | 6,782 |  |  | 8,090 |  |  | 14,872 |  |  | — |  |  | 14,872 |
Accrued interest receivable | 4,138 |  |  | — |  |  | 4,138 |  |  | — |  |  | 4,138 |
Deferred income taxes | 2,017 |  |  | (3,298 | ) |  | (1,281 | ) |  | 311 |  |  | (970 | )
Core deposits and other intangible assets | 269 |  |  | (269 | ) |  | — |  |  | — |  |  | — |
Other assets | 24,883 |  |  | (4,278 | ) |  | 20,605 |  |  | 40 |  |  | 20,645 |
Total Assets Acquired | 1,137,088 |  |  | (16,753 | ) |  | 1,120,335 |  |  | (2,145 | ) |  | 1,118,190 |
Fair Value of Liabilities Assumed |  |  |  |  |  |  |  |  |
Deposits | 966,263 |  |  | 1,002 |  |  | 967,265 |  |  | (12 | ) |  | 967,253 |
Borrowings | 37,617 |  |  | (276 | ) |  | 37,341 |  |  | (257 | ) |  | 37,084 |
Accrued interest payable and other liabilities | 11,157 |  |  | (3,184 | ) |  | 7,973 |  |  | (68 | ) |  | 7,905 |
Total Liabilities Assumed | 1,015,037 |  |  | (2,458 | ) |  | 1,012,579 |  |  | (337 | ) |  | 1,012,242 |
Total Net Assets Acquired | $ | 122,051 |  |  | $ | (14,295 | ) |  | $ | 107,756 |  |  | $ | (1,808 | ) |  | $ | 105,948 |
Core Deposit Intangible Asset |  |  |  |  | $ | 7,288 |  |  | $ | — |  |  | $ | 7,288 |
Wealth Management Intangible Asset |  |  |  |  | 1,772 |  |  | — |  |  | 1,772 |
Total Fair Value of Net Assets Acquired and Identified |  |  |  |  | $ | 116,816 |  |  | $ | (1,808 | ) |  | $ | 115,008 |
Consideration Paid |  |  |  |  |  |  |  |  |
Cash |  |  |  |  | $ | 360 |  |  | $ | — |  |  | $ | 360 |
Common stock |  |  |  |  | 200,631 |  |  | — |  |  | 200,631 |
Fair Value of Total Consideration |  |  |  |  | $ | 200,991 |  |  | $ | — |  |  | $ | 200,991 |
Goodwill |  |  |  |  | $ | 84,175 |  |  | $ | 1,808 |  |  | $ | 85,983 |

10

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 2. BUSINESS COMBINATIONS – continued
(1)Management is continuing to evaluate the purchase accounting fair value adjustments related to loans, including loan classification, deferred and current income taxes until the final valuations are complete and final tax returns are filed. Any changes in preliminary estimates will be adjusted in goodwill in subsequent periods, but not extending beyond one year from the date of acquisition.
Loans acquired in the Merger were recorded at fair value with no carryover of the related ACL from DNB. Determining the fair value of the loans involves estimating the amount and timing of principal and interest cash flows expected to be collected on the loans and discounting those cash flows at a market rate of interest. The preliminary fair value of the loans acquired was estimated at $909.0 million, net of a $10.5 million discount. The discount is accreted to interest income over the remaining contractual life of the loans. During the three month period ended March 31, 2020, the fair value of acquired loans was reduced by an additional $2.5 million as we continue to finalize our evaluation of the loan portfolio.
As of March 31, 2020, direct costs related to the DNB merger of $13.7 million were recognized and expensed as incurred. During the three months ended March 31, 2020, we recognized $2.3 million of merger related expenses including $0.2 million in legal and professional fees, $1.4 million in severance payments and stay-bonuses, $0.4 million for data processing, and $0.3 million in other expenses. As of December 31, 2019, we recognized $11.4 million of merger related expenses, including $4.7 million for data processing contract termination and system conversion costs, $2.8 million in legal and professional expenses, $3.4 million in severance payments and $0.5 million in other expenses.
11

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 3. EARNINGS PER SHARE
Diluted earnings per share is calculated using both the two-class and the treasury stock methods with the more dilutive method used to determine diluted earnings per share. The following table reconciles the numerators and denominators of basic and diluted earnings per share calculations for the periods presented.

| Three Months Ended March 31,
(in thousands, except share and per share data) | 2020 |  | 2019
Numerator for Earnings per Share—Basic: |  |  |  |  |
Net income |  | $ | 13,231 |  |  |  | $ | 22,928 |
Less: Income allocated to participating shares |  | 29 |  |  |  | 62 |
Net Income Allocated to Shareholders |  | $ | 13,202 |  |  |  | $ | 22,866 |
Numerator for Earnings per Share—Diluted: |  |  |  |  |
Net income |  | $ | 13,231 |  |  |  | $ | 22,928 |
Net Income Available to Shareholders |  | $ | 13,231 |  |  |  | $ | 22,928 |
Denominators for Earnings per Share: |  |  |  |  |
Weighted Average Shares Outstanding—Basic |  | 39,271,540 |  |  |  | 34,414,555 |
Add: Potentially dilutive shares |  | 108,116 |  |  |  | 128,256 |
Denominator for Treasury Stock Method—Diluted |  | 39,379,656 |  |  |  | 34,542,811 |
Weighted Average Shares Outstanding—Basic |  | 39,271,540 |  |  |  | 34,414,555 |
Add: Average participating shares outstanding |  | 54,398 |  |  |  | 92,659 |
Denominator for Two-Class Method—Diluted |  | 39,325,938 |  |  |  | 34,507,214 |
Earnings per share—basic |  | $ | 0.34 |  |  |  | $ | 0.67 |
Earnings per share—diluted |  | $ | 0.34 |  |  |  | $ | 0.66 |
Restricted stock considered anti-dilutive excluded from potentially dilutive shares |  | 41 |  |  |  | 68,314 |

12

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 4. FAIR VALUE MEASUREMENTS
We use fair value measurements when recording and disclosing certain financial assets and liabilities. Debt securities, equity securities and derivative financial instruments are recorded at fair value on a recurring basis. Additionally, from time to time, we may be required to record other assets at fair value on a nonrecurring basis, such as loans held for sale, loans held for investment, other real estate owned, or OREO, and other repossessed assets, mortgage servicing rights, or MSRs, and certain other assets.
Fair value is the price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market in an orderly transaction between market participants at the measurement date. An orderly transaction is a transaction that assumes exposure to the market for a period prior to the measurement date to allow for marketing activities that are usual and customary for transactions involving such assets or liabilities; it is not a forced transaction. In determining fair value, we use various valuation approaches, including market, income and cost approaches. The fair value standard establishes a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing an asset or liability, which are developed based on market data that we have obtained from independent sources. Unobservable inputs reflect our estimates of assumptions that market participants would use in pricing an asset or liability, which are developed based on the best information available in the circumstances.
The fair value hierarchy gives the highest priority to unadjusted quoted market prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority to unobservable inputs (Level 3 measurement). The fair value hierarchy is broken down into three levels based on the reliability of inputs as follows:
Level 1: valuation is based upon unadjusted quoted market prices for identical instruments traded in active markets.
Level 2: valuation is based upon quoted market prices for similar instruments traded in active markets, quoted market prices for identical or similar instruments traded in markets that are not active and model-based valuation techniques for which all significant assumptions are observable in the market or can be corroborated by market data.
Level 3: valuation is derived from other valuation methodologies, including discounted cash flow models and similar techniques that use significant assumptions not observable in the market. These unobservable assumptions reflect estimates of assumptions that market participants would use in determining fair value.
A financial instrument’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. Our policy is to recognize transfers between any of the fair value hierarchy levels at the end of the reporting period in which the transfer occurred.
The following are descriptions of the valuation methodologies that we use for financial instruments recorded at fair value on either a recurring or nonrecurring basis.
Recurring Basis
Available-for-Sale Debt Securities
We obtain fair values for debt securities from a third-party pricing service which utilizes several sources for valuing fixed-income securities. We validate prices received from our pricing service through comparison to a secondary pricing service and broker quotes. We review the methodologies of the pricing services which provide us with a sufficient understanding of the valuation models, assumptions, inputs and pricing to reasonably measure the fair value of our debt securities. The market valuation sources for debt securities include observable inputs rather than significant unobservable inputs and are classified as Level 2. The service provider utilizes pricing models that vary by asset class and include available trade, bid and other market information. Generally, the methodologies include broker quotes, proprietary models, vast descriptive terms and conditions databases, and extensive quality control programs.
Equity Securities
Marketable equity securities that have an active, quotable market are classified as Level 1. Marketable equity securities that are quotable, but are thinly traded or inactive, are classified as Level 2. Marketable equity securities that are not readily traded and do not have a quotable market are classified as Level 3.
13

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 4. FAIR VALUE MEASUREMENTS - continued
Deferred Compensation Plan Assets
We use quoted market prices to determine the fair value of our equity security assets. These securities are reported at fair value with the gains and losses included in noninterest income in our Consolidated Statements of Comprehensive Income. These assets are held in a deferred compensation plan and are invested in readily quoted mutual funds. Accordingly, these assets are classified as Level 1. Deferred compensation plan assets are reported in other assets in the Consolidated Balance Sheets.
Derivative Financial Instruments
We use derivative instruments, including interest rate swaps for commercial loans with our customers, interest rate lock commitments and the sale of mortgage loans in the secondary market. We calculate the fair value for derivatives using accepted valuation techniques, including discounted cash flow analysis on the expected cash flows of each derivative. Each valuation considers the contractual terms of the derivative, including the period to maturity, and uses observable market-based inputs, such as interest rate curves and implied volatilities. Accordingly, derivatives are classified as Level 2. We incorporate credit valuation adjustments into the valuation models to appropriately reflect both our own nonperformance risk and the respective counterparties’ nonperformance risk in calculating fair value measurements. In adjusting the fair value of our derivative contracts for the effect of nonperformance risk, we have considered the impact of netting and any applicable credit enhancements and collateral postings.
Nonrecurring Basis
Loans Held for Sale
Loans held for sale consist of 1-4 family residential loans originated for sale in the secondary market and, from time to time, certain loans are transferred from the loan portfolio to loans held for sale, all of which are carried at the lower of cost or fair value. The fair value of 1-4 family residential loans is based on the principal or most advantageous market currently offered for similar loans using observable market data. The fair value of the loans transferred from the loan portfolio is based on the amounts offered for these loans in currently pending sales transactions. Loans held for sale carried at fair value are classified as Level 3.
Loans Held for Investment
Loans that are individually evaluated to determine whether a specific allocation of ACL is needed are reported at fair value. Fair value is determined using the following methods: 1) the present value of expected future cash flows discounted at the loan’s original effective interest rate; 2) the loan’s observable market price; or 3) the fair value of the collateral less estimated selling costs when the loan is collateral dependent and we expect to liquidate the collateral. However, if repayment is expected to come from the operation of the collateral, rather than liquidation, then we do not consider estimated selling costs in determining the fair value of the collateral. Collateral values are generally based upon appraisals by approved, independent state certified appraisers. Appraisals may be discounted based on our historical knowledge, changes in market conditions from the time of appraisal or our knowledge of the borrower and the borrower’s business. Loans carried at fair value are classified as Level 3.
OREO and Other Repossessed Assets
OREO and other repossessed assets obtained in partial or total satisfaction of a loan are recorded at the lower of recorded investment in the loan or fair value less cost to sell. Subsequent to foreclosure, these assets are carried at the lower of the amount recorded at acquisition date or fair value less cost to sell. Accordingly, it may be necessary to record nonrecurring fair value adjustments. Fair value, when recorded, is generally based upon appraisals by approved, independent state certified appraisers. Appraisals on OREO may be discounted based on our historical knowledge, changes in market conditions from the time of appraisal or other information available to us. OREO and other repossessed assets carried at fair value are classified as Level 3.
14

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 4. FAIR VALUE MEASUREMENTS - continued
Mortgage Servicing Rights
The fair value of MSRs is determined by calculating the present value of estimated future net servicing cash flows, considering expected mortgage loan prepayment rates, discount rates, servicing costs and other economic factors, which are determined based on current market conditions. The expected rate of mortgage loan prepayments is the most significant factor driving the value of MSRs. MSRs are considered impaired if the carrying value exceeds fair value. Since the valuation model includes significant unobservable inputs as listed above, MSRs are classified as Level 3. MSRs are reported in other assets in the Consolidated Balance Sheets and are amortized into mortgage banking income in the Consolidated Statements of Comprehensive Income.
Other Assets
We measure certain other assets at fair value on a nonrecurring basis. Fair value is based on the application of lower of cost or fair value accounting, or write-downs of individual assets. Valuation methodologies used to measure fair value are consistent with overall principles of fair value accounting and consistent with those described above.
Financial Instruments
In addition to financial instruments recorded at fair value in our financial statements, fair value accounting guidance requires disclosure of the fair value of all of an entity’s assets and liabilities that are considered financial instruments. The majority of our assets and liabilities are considered financial instruments. Many of these instruments lack an available trading market as characterized by a willing buyer and a willing seller engaged in an exchange transaction. Also, it is our general practice and intent to hold our financial instruments to maturity and to not engage in trading or sales activities with respect to such financial instruments. For fair value disclosure purposes, we substantially utilize the fair value measurement criteria as required and explained above. In cases where quoted fair values are not available, we use present value methods to determine the fair value of our financial instruments.
Cash and Cash Equivalents
The carrying amounts reported in the Consolidated Balance Sheets for cash and due from banks, including interest-bearing deposits, approximate fair value.
Loans
The fair value of variable rate loans that may reprice frequently at short-term market rates is based on carrying values adjusted for liquidity and credit risk. The fair value of variable rate loans that reprice at intervals of one year or longer, such as adjustable rate mortgage products, is estimated using discounted cash flow analyses that utilize interest rates currently being offered for similar loans and adjusted for liquidity and credit risk. The fair value of fixed rate loans is estimated using a discounted cash flow analysis that utilizes interest rates currently being offered for similar loans adjusted for liquidity and credit risk.
Bank Owned Life Insurance
Fair value approximates net cash surrender value of bank owned life insurance, or BOLI.
Federal Home Loan Bank, or FHLB, and Other Restricted Stock
It is not practical to determine the fair value of our FHLB and other restricted stock due to the restrictions placed on the transferability of these stocks; it is presented at carrying value.
Deposits
The fair values disclosed for deposits without defined maturities (e.g., noninterest and interest-bearing demand, money market and savings accounts) are by definition equal to the amounts payable on demand. The carrying amounts for variable rate, fixed-term time deposits approximate their fair values. Estimated fair values for fixed rate and other time deposits are based on discounted cash flow analysis using interest rates currently offered for time deposits with similar terms. The carrying amount of accrued interest approximates fair value.
15

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 4. FAIR VALUE MEASUREMENTS - continued
Short-Term Borrowings
The carrying amounts of securities sold under repurchase agreements, or REPOs, and other short-term borrowings approximate their fair values.
Long-Term Borrowings
The fair values disclosed for fixed rate long-term borrowings are determined by discounting their contractual cash flows using current interest rates for long-term borrowings of similar remaining maturities. The carrying amounts of variable rate long-term borrowings approximate their fair values.
Junior Subordinated Debt Securities
The interest rate on the variable rate junior subordinated debt securities is reset quarterly; therefore, the carrying values approximate their fair values.
Loan Commitments and Standby Letters of Credit
Off-balance sheet financial instruments consist of commitments to extend credit and letters of credit. Except for interest rate lock commitments, estimates of the fair value of these off-balance sheet items are not made because of the short-term nature of these arrangements and the credit standing of the counterparties.
Other
Estimates of fair value are not made for items that are not defined as financial instruments, including such items as our core deposit intangibles and the value of our trust operations.
16

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 4. FAIR VALUE MEASUREMENTS - continued
Assets and Liabilities Recorded at Fair Value on a Recurring Basis
The following tables present our assets and liabilities that are measured at fair value on a recurring basis by fair value hierarchy level at March 31, 2020 and December 31, 2019. There were no transfers between Level 1 and Level 2 for items measured at fair value on a recurring basis during the periods presented.

| March 31, 2020
(dollars in thousands) | Level 1 |  | Level 2 |  | Level 3 |  | Total
ASSETS |  |  |  |  |  |  |
Available-for-sale debt securities: |  |  |  |  |  |  |
U.S. Treasury securities | $ | — |  |  | $ | 10,372 |  |  | $ | — |  |  | $ | 10,372 |
Obligations of U.S. government corporations and agencies | — |  |  | 137,982 |  |  | — |  |  | 137,982 |
Collateralized mortgage obligations of U.S. government corporations and agencies | — |  |  | 189,472 |  |  | — |  |  | 189,472 |
Residential mortgage-backed securities of U.S. government corporations and agencies | — |  |  | 21,193 |  |  | — |  |  | 21,193 |
Commercial mortgage-backed securities of U.S. government corporations and agencies | — |  |  | 284,679 |  |  | — |  |  | 284,679 |
Corporate Bonds | — |  |  | 7,551 |  |  | — |  |  | 7,551 |
Obligations of states and political subdivisions | — |  |  | 144,717 |  |  | — |  |  | 144,717 |
Total Available-for-sale Debt Securities | — |  |  | 795,966 |  |  | — |  |  | 795,966 |
Marketable equity securities | 3,504 |  |  | 62 |  |  | — |  |  | 3,566 |
Total Securities | 3,504 |  |  | 796,028 |  |  | — |  |  | 799,532 |
Securities held in a deferred compensation plan | 4,782 |  |  | — |  |  | — |  |  | 4,782 |
Derivative financial assets: |  |  |  |  |  |  |
Interest rate swaps | — |  |  | 88,135 |  |  | — |  |  | 88,135 |
Interest rate lock commitments | — |  |  | 2,927 |  |  | — |  |  | 2,927 |
Total Assets | $ | 8,286 |  |  | $ | 887,090 |  |  | $ | — |  |  | $ | 895,376 |
LIABILITIES |  |  |  |  |  |  |
Derivative financial liabilities: |  |  |  |  |  |  |
Interest rate swaps | $ | — |  |  | $ | 87,989 |  |  | $ | — |  |  | $ | 87,989 |
Forward sale contracts | — |  |  | 1,292 |  |  | — |  |  | 1,292 |
Total Liabilities | $ | — |  |  | $ | 89,281 |  |  | $ | — |  |  | $ | 89,281 |

17

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 4. FAIR VALUE MEASUREMENTS - continued

|  | December 31, 2019
(dollars in thousands) |  | Level 1 |  |  | Level 2 |  |  | Level 3 |  |  | Total
ASSETS |  |  |  |  |  |  |  |  |  |  |
Available-for-sale debt securities: |  |  |  |  |  |  |  |  |  |  |
U.S. Treasury securities |  | $ | — |  |  |  | $ | 10,040 |  |  |  | $ | — |  |  |  | $ | 10,040 |
Obligations of U.S. government corporations and agencies |  | — |  |  |  | 157,697 |  |  |  | — |  |  |  | 157,697 |
Collateralized mortgage obligations of U.S. government corporations and agencies |  | — |  |  |  | 189,348 |  |  |  | — |  |  |  | 189,348 |
Residential mortgage-backed securities of U.S. government corporations and agencies |  | — |  |  |  | 22,418 |  |  |  | — |  |  |  | 22,418 |
Commercial mortgage-backed securities of U.S. government corporations and agencies |  | — |  |  |  | 275,870 |  |  |  | — |  |  |  | 275,870 |
Corporate Bonds |  | — |  |  |  | 7,627 |  |  |  | — |  |  |  | 7,627 |
Obligations of states and political subdivisions |  | — |  |  |  | 116,133 |  |  |  | — |  |  |  | 116,133 |
Total Available-for-Sale Debt Securities |  | — |  |  |  | 779,133 |  |  |  | — |  |  |  | 779,133 |
Marketable equity securities |  | 5,078 |  |  |  | 72 |  |  |  | — |  |  |  | 5,150 |
Total Securities |  | 5,078 |  |  |  | 779,205 |  |  |  | — |  |  |  | 784,283 |
Securities held in a deferred compensation plan |  | 5,987 |  |  |  | — |  |  |  | — |  |  |  | 5,987 |
Derivative financial assets: |  |  |  |  |  |  |  |  |  |  |
Interest rate swaps |  | — |  |  |  | 25,647 |  |  |  | — |  |  |  | 25,647 |
Interest rate lock commitments |  | — |  |  |  | 321 |  |  |  | — |  |  |  | 321 |
Forward sale contracts |  | — |  |  |  | 1 |  |  |  | — |  |  |  | 1 |
Total Assets |  | $ | 11,065 |  |  |  | $ | 805,174 |  |  |  | $ | — |  |  |  | $ | 816,239 |
LIABILITIES |  |  |  |  |  |  |  |  |  |  |
Derivative financial liabilities: |  |  |  |  |  |  |  |  |  |  |
Interest rate swaps |  | $ | — |  |  |  | $ | 25,615 |  |  |  | $ | — |  |  |  | $ | 25,615 |
Total Liabilities |  | $ | — |  |  |  | $ | 25,615 |  |  |  | $ | — |  |  |  | $ | 25,615 |

Assets Recorded at Fair Value on a Nonrecurring Basis
We may be required to measure certain assets and liabilities at fair value on a nonrecurring basis. Nonrecurring assets are recorded at the lower of cost or fair value in our financial statements. There were no liabilities measured at fair value on a nonrecurring basis at either March 31, 2020 or December 31, 2019.
For Level 3 assets measured at fair value on a nonrecurring basis as of March 31, 2020 and December 31, 2019, the significant unobservable inputs used in the fair value measurements were as follows:

| March 31, 2020 | Valuation Technique(s) |  | Significant Unobservable Inputs |  | Range
(dollars in thousands) |  |  |  |  |  |  |  |
Loans held for investment | $ | 20,926 |  |  | Collateral Method | Third party appraisal |  | Costs to sell |  | 0% - 17%
|  |  | Discounted cash flow method | Discount rate |  | Contractual loan rate |  | 3.25%
Other real estate owned | 3,045 |  |  | Collateral method | Third party appraisal |  | Costs to sell |  | 7%
Mortgage servicing rights | 3,929 |  |  | Discounted cash flow method | Third party service provider |  | Discount rate |  | 9.39% - 12.54%
|  |  |  |  |  | Constant prepayment rates |  | 7.46% - 12.74%
Total Assets | $ | 27,900 |  |  |

18

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 4. FAIR VALUE MEASUREMENTS - continued

| December 31, 2019 | Valuation Technique(s) |  | Significant Unobservable Inputs |  | Range
(dollars in thousands) |  |  |  |  |  |  |  |
Impaired loans | $ | 38,697 |  |  | Collateral Method | Third party appraisal |  | Costs to sell |  | 0% - 20%
|  |  | Discounted cash flow method | Discount rate |  | Contractual loan rate |  | 4.75% - 5.50%
Other real estate owned | 3,231 |  |  | Collateral method | Third party appraisal |  | Costs to sell |  | 7%
Mortgage servicing rights | 1,134 |  |  | Discounted cash flow method | Third party service provider |  | Discount rate |  | 9.39% - 12.54%
|  |  |  |  |  | Constant prepayment rates |  | 7.46% - 12.74%
Total Assets | $ | 43,062 |  |  |

19

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 4. FAIR VALUE MEASUREMENTS - continued
The carrying values and fair values of our financial instruments at March 31, 2020 and December 31, 2019 are presented in the following tables:

| Carrying Value(1) |  | Fair Value Measurements at March 31, 2020
(dollars in thousands) |  | Total |  | Level 1 |  | Level 2 |  | Level 3
ASSETS |  |  |  |  |  |  |  |  |
Cash and due from banks, including interest-bearing deposits | $ | 187,684 |  |  | $ | 187,684 |  |  | $ | 187,684 |  |  | $ | — |  |  | $ | — |
Securities | 799,532 |  |  | 799,532 |  |  | 3,504 |  |  | 796,028 |  |  | — |
Loans held for sale | 7,309 |  |  | 7,309 |  |  | — |  |  | — |  |  | 7,309 |
Portfolio loans, net | 7,149,895 |  |  | 7,090,570 |  |  | — |  |  | — |  |  | 7,090,570 |
Bank owned life insurance | 80,978 |  |  | 80,798 |  |  | — |  |  | 80,798 |  |  | — |
FHLB and other restricted stock | 28,253 |  |  | 28,253 |  |  | — |  |  | — |  |  | 28,253 |
Securities held in a deferred compensation plan | 4,782 |  |  | 4,782 |  |  | 4,782 |  |  | — |  |  | — |
Mortgage servicing rights | 3,979 |  |  | 3,982 |  |  | — |  |  | — |  |  | 3,982 |
Interest rate swaps | 88,135 |  |  | 88,135 |  |  | — |  |  | 88,135 |  |  | — |
Interest rate lock commitments | 2,927 |  |  | 2,927 |  |  | — |  |  | 2,927 |  |  | — |
LIABILITIES |  |  |  |  |  |  |  |  |
Deposits | $ | 7,057,879 |  |  | $ | 7,065,896 |  |  | $ | 5,469,826 |  |  | $ | 1,596,070 |  |  | $ | — |
Securities sold under repurchase agreements | 69,644 |  |  | 69,644 |  |  | 69,644 |  |  | — |  |  | — |
Short-term borrowings | 410,240 |  |  | 410,240 |  |  | 410,240 |  |  | — |  |  | — |
Long-term borrowings | 50,180 |  |  | 51,675 |  |  | 4,630 |  |  | 47,045 |  |  | — |
Junior subordinated debt securities | 64,038 |  |  | 64,038 |  |  | 64,038 |  |  | — |  |  | — |
Interest rate swaps | 87,989 |  |  | 87,989 |  |  | — |  |  | 87,989 |  |  | — |
Forward sales contracts | 1,292 |  |  | 1,292 |  |  | — |  |  | 1,292 |  |  | — |
(1) As reported in the Consolidated Balance Sheets |  |  |  |  |  |  |  |  |

| Carrying Value(1) |  | Fair Value Measurements at December 31, 2019
(dollars in thousands) |  | Total |  | Level 1 |  | Level 2 |  | Level 3
ASSETS |  |  |  |  |  |  |  |  |
Cash and due from banks, including interest-bearing deposits | $ | 197,823 |  |  | $ | 197,823 |  |  | $ | 197,823 |  |  | $ | — |  |  | $ | — |
Securities | 784,283 |  |  | 784,283 |  |  | 5,078 |  |  | 779,205 |  |  | — |
Loans held for sale | 5,256 |  |  | 5,256 |  |  | — |  |  | — |  |  | 5,256 |
Portfolio loans, net | 7,074,928 |  |  | 6,940,875 |  |  | — |  |  | — |  |  | 6,940,875 |
Bank owned life insurance | 80,473 |  |  | 80,473 |  |  | — |  |  | 80,473 |  |  | — |
FHLB and other restricted stock | 22,977 |  |  | 22,977 |  |  | — |  |  | — |  |  | 22,977 |
Securities held in a Deferred Compensation Plan | 5,987 |  |  | 5,987 |  |  | 5,987 |  |  | — |  |  | — |
Mortgage servicing rights | 4,662 |  |  | 4,650 |  |  | — |  |  | — |  |  | 4,650 |
Interest rate swaps | 25,647 |  |  | 25,647 |  |  | — |  |  | 25,647 |  |  | — |
Interest rate lock commitments | 321 |  |  | 321 |  |  | — |  |  | 321 |  |  | — |
Forward sale contracts | 1 |  |  | 1 |  |  | — |  |  | 1 |  |  | — |
LIABILITIES |  |  |  |  |  |  |  |  |
Deposits | $ | 7,036,576 |  |  | $ | 7,034,595 |  |  | $ | 5,441,143 |  |  | $ | 1,593,452 |  |  | $ | — |
Securities sold under repurchase agreements | 19,888 |  |  | 19,888 |  |  | 19,888 |  |  | — |  |  | — |
Short-term borrowings | 281,319 |  |  | 281,319 |  |  | 281,319 |  |  | — |  |  | — |
Long-term borrowings | 50,868 |  |  | 51,339 |  |  | 4,678 |  |  | 46,661 |  |  | — |
Junior subordinated debt securities | 64,277 |  |  | 64,277 |  |  | 64,277 |  |  | — |  |  | — |
Interest rate swaps | 25,615 |  |  | 25,615 |  |  | — |  |  | 25,615 |  |  | — |
(1) As reported in the Consolidated Balance Sheets |  |  |  |  |  |  |  |  |

20

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 5. SECURITIES
The following table presents the fair values of our securities portfolio at the dates presented:

(dollars in thousands) | March 31, 2020 |  | December 31, 2019
Available-for-sale debt securities |  | $ | 795,966 |  |  |  | $ | 779,133 |
Marketable equity securities |  | 3,566 |  |  |  | 5,150 |
Total Securities |  | $ | 799,532 |  |  |  | $ | 784,283 |

Available-for-Sale Debt Securities
The following tables present the amortized cost and fair value of available-for-sale debt securities as of the dates presented:

| March 31, 2020 |  | December 31, 2019
(dollars in thousands) | Amortized Cost |  |  | Gross Unrealized Gains |  |  | Gross Unrealized Losses |  |  | Fair Value |  |  | Amortized Cost |  |  | Gross Unrealized Gains |  |  | Gross Unrealized Losses |  |  | Fair Value |
U.S. Treasury securities |  | $ | 9,972 |  |  |  | $ | 400 |  |  |  | $ | — |  |  |  | $ | 10,372 |  |  |  | $ | 9,969 |  |  |  | $ | 71 |  |  |  | $ | — |  |  |  | $ | 10,040 |
Obligations of U.S. government corporations and agencies |  | 132,938 |  |  |  | 5,044 |  |  |  | — |  |  |  | 137,982 |  |  |  | 155,969 |  |  |  | 1,773 |  |  |  | (45 | ) |  |  | 157,697 |
Collateralized mortgage obligations of U.S. government corporations and agencies |  | 180,682 |  |  |  | 8,790 |  |  |  | — |  |  |  | 189,472 |  |  |  | 186,879 |  |  |  | 2,773 |  |  |  | (304 | ) |  |  | 189,348 |
Residential mortgage-backed securities of U.S. government corporations and agencies |  | 20,391 |  |  |  | 802 |  |  |  | — |  |  |  | 21,193 |  |  |  | 22,120 |  |  |  | 321 |  |  |  | (23 | ) |  |  | 22,418 |
Commercial mortgage-backed securities of U.S. government corporations and agencies |  | 272,651 |  |  |  | 12,028 |  |  |  | — |  |  |  | 284,679 |  |  |  | 273,771 |  |  |  | 2,680 |  |  |  | (581 | ) |  |  | 275,870 |
Corporate obligations |  | 7,532 |  |  |  | 30 |  |  |  | (11 | ) |  |  | 7,551 |  |  |  | 7,603 |  |  |  | 24 |  |  |  | — |  |  |  | 7,627 |
Obligations of states and political subdivisions |  | 139,530 |  |  |  | 5,187 |  |  |  | — |  |  |  | 144,717 |  |  |  | 112,116 |  |  |  | 4,017 |  |  |  | — |  |  |  | 116,133 |
Total Available-for-Sale Debt Securities (1) |  | $ | 763,696 |  |  |  | $ | 32,281 |  |  |  | $ | (11 | ) |  |  | $ | 795,966 |  |  |  | $ | 768,427 |  |  |  | $ | 11,659 |  |  |  | $ | (953 | ) |  |  | $ | 779,133 |

(1) Excludes interest receivable of $3.5 million at March 31, 2020 and $3.4 million at December 31, 2019. Interest receivable is included in other assets in the consolidated balance sheets.
21

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 5. SECURITIES – continued
The following tables present the fair value and the age of gross unrealized losses on available-for-sale debt securities by investment category as of the dates presented:

| March 31, 2020
| Less Than 12 Months |  | 12 Months or More |  | Total
(dollars in thousands) | Number of Securities |  | Fair Value |  |  | Unrealized Losses |  |  | Number of Securities |  | Fair Value |  |  | Unrealized Losses |  |  | Number of Securities |  | Fair Value |  |  | Unrealized Losses |
U.S. Treasury securities | — |  | $ | — |  |  | $ | — |  |  | — |  | $ | — |  |  | $ | — |  |  | — |  | $ | — |  |  | $ | — |
Obligations of U.S. government corporations and agencies | — |  | — |  |  | — |  |  | — |  | — |  |  | — |  |  | — |  | — |  |  | — |
Collateralized mortgage obligations of U.S. government corporations and agencies | — |  | — |  |  | — |  |  | — |  | — |  |  | — |  |  | — |  | — |  |  | — |
Residential mortgage-backed securities of U.S. government corporations and agencies | — |  | — |  |  | — |  |  | — |  | — |  |  | — |  |  | — |  | — |  |  | — |
Commercial mortgage-backed securities of U.S. government corporations and agencies | — |  | — |  |  | — |  |  | — |  | — |  |  | — |  |  | — |  | — |  |  | — |
Corporate bonds | 2 |  | 2,989 |  |  | (11 | ) |  | — |  | — |  |  | — |  |  | 2 |  | 2,989 |  |  | (11 | )
Obligations of states and political subdivisions | — |  | — |  |  | — |  |  | — |  | — |  |  | — |  |  | — |  | — |  |  | — |
Total | 2 |  | $ | 2,989 |  |  | $ | (11 | ) |  | — |  | $ | — |  |  | $ | — |  |  | 2 |  | $ | 2,989 |  |  | $ | (11 | )

| December 31, 2019
| Less Than 12 Months |  | 12 Months or More |  | Total
(dollars in thousands) | Number of Securities |  | Fair Value |  |  | Unrealized Losses |  |  | Number of Securities |  | Fair Value |  |  | Unrealized Losses |  |  | Number of Securities |  | Fair Value |  |  | Unrealized Losses |
U.S. Treasury securities | — |  | $ | — |  |  | $ | — |  |  | — |  | $ | — |  |  | $ | — |  |  | — |  | $ | — |  |  | $ | — |
Obligations of U.S. government corporations and agencies | 3 |  | 22,638 |  |  | (45 | ) |  | — |  | — |  |  | — |  |  | 3 |  | 22,638 |  |  | (45 | )
Collateralized mortgage obligations of U.S. government corporations and agencies | 6 |  | 23,393 |  |  | (73 | ) |  | 6 |  | 25,254 |  |  | (231 | ) |  | 12 |  | 48,647 |  |  | (304 | )
Residential mortgage-backed securities of U.S. government corporations and agencies | 1 |  | 982 |  |  | (2 | ) |  | 1 |  | 2,534 |  |  | (21 | ) |  | 2 |  | 3,516 |  |  | (23 | )
Commercial mortgage-backed securities of U.S. government corporations and agencies | 9 |  | 90,005 |  |  | (581 | ) |  | — |  | — |  |  | — |  |  | 9 |  | 90,005 |  |  | (581 | )
Corporate bonds | 1 |  | 79 |  |  | — |  |  | — |  | — |  |  | — |  |  | 1 |  | 79 |  |  | — |
Obligations of states and political subdivisions | — |  | — |  |  | — |  |  | — |  | — |  |  | — |  |  | — |  | — |  |  | — |
Total Temporarily Impaired Debt Securities | 20 |  | $ | 137,097 |  |  | $ | (701 | ) |  | 7 |  | $ | 27,788 |  |  | $ | (252 | ) |  | 27 |  | $ | 164,885 |  |  | $ | (953 | )

We evaluate quarterly securities with unrealized losses to determine if the decline in fair value has resulted from credit losses or other factors. There were two debt securities in an unrealized loss position at March 31, 2020 and 27 debt securities in an unrealized loss position at December 31, 2019. We do not intend to sell and it is more likely than not that we will not be required to sell any of the securities in an unrealized loss position before recovery of their amortized cost. The unrealized losses on debt securities were attributable to changes in interest rates and not related to the credit quality of these issuers. All debt securities were determined to be investment grade and paying principal and interest according to the contractual terms of the security. We concluded that the allowance for credit losses for debt securities was immaterial at March 31, 2020. Prior to the adoption of ASU 2016-13 there was no other than temporary impairment, or OTTI, recorded during the three months ended March 31, 2019.
22

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 5. SECURITIES – continued
The following table presents net unrealized gains and losses, net of tax, on available-for-sale debt securities included in accumulated other comprehensive income/(loss), for the periods presented:

| March 31, 2020 |  | December 31, 2019
(dollars in thousands) | Gross Unrealized Gains |  |  | Gross Unrealized Losses |  |  | Net Unrealized Gains/(Losses) |  |  | Gross Unrealized Gains |  |  | Gross Unrealized Losses |  |  | Net Unrealized Gains/(Losses) |
Total unrealized gains/(losses) on available-for-sale debt securities | $ | 32,281 |  |  | $ | (11 | ) |  | $ | 32,270 |  |  | $ | 11,659 |  |  | $ | (953 | ) |  | $ | 10,706 |
Income tax (expense) benefit | (6,873 | ) |  | 2 |  |  | (6,871 | ) |  | (2,486 | ) |  | 203 |  |  | (2,283 | )
Net Unrealized Gains/(Losses), Net of Tax Included in Accumulated Other Comprehensive Income/(Loss) | $ | 25,408 |  |  | $ | (9 | ) |  | $ | 25,399 |  |  | $ | 9,173 |  |  | $ | (750 | ) |  | $ | 8,423 |

The amortized cost and fair value of available-for-sale debt securities at March 31, 2020 by contractual maturity are included in the table below. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties.

| March 31, 2020
(dollars in thousands) | Amortized Cost |  |  | Fair Value |
Obligations of the U.S. Treasury, U.S. government corporations and agencies, and obligations of states and political subdivisions |  |  |
Due in one year or less | $ | 84,687 |  |  | $ | 85,259 |
Due after one year through five years | 100,877 |  |  | 106,112 |
Due after five years through ten years | 65,732 |  |  | 68,913 |
Due after ten years | 31,144 |  |  | 32,786 |
Available-for-Sale Debt Securities With Maturities | 282,440 |  |  | 293,070 |
Collateralized mortgage obligations of U.S. government corporations and agencies | 180,682 |  |  | 189,473 |
Residential mortgage-backed securities of U.S. government corporations and agencies | 20,391 |  |  | 21,193 |
Commercial mortgage-backed securities of U.S. government corporations and agencies | 272,651 |  |  | 284,679 |
Corporate Securities | 7,532 |  |  | 7,551 |
Total Available-for-Sale Debt Securities | $ | 763,696 |  |  | $ | 795,966 |

Debt securities with carrying values of $298.4 million at March 31, 2020 and $286.0 million at December 31, 2019 were pledged for various regulatory and legal requirements.
Marketable Equity Securities
The following table presents realized and unrealized net gains and losses for our marketable equity securities for the periods presented:

| Three Months Ended March 31,
(dollars in thousands) | 2020 |  |  | 2019 |
Marketable Equity Securities |  |  |  |  |
Net gains and losses recognized during the period on equity securities | $ | (1,585 | ) |  | $ | (318 | )
Less: Net gains and losses recognized during the period on equity securities sold during the period | — |  |  | — |
Unrealized Losses/Gains Recognized During the Reporting Period on Equity Securities Still Held at the Reporting Date | $ | (1,585 | ) |  | $ | (318 | )

Total unrealized gains and losses on marketable equity securities recognized during the current period are included in other noninterest income on the Consolidated Statements of Comprehensive Income.
23

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 6. LOANS AND LOANS HELD FOR SALE
Loans are presented net of unearned income of $5.0 million at March 31, 2020 and $4.6 million at December 31, 2019 and net of a discount related to purchase accounting fair value adjustments of $10.9 million and $12.3 million at March 31, 2020 and December 31, 2019. The following table presents loans as of the dates presented:

(dollars in thousands) | March 31, 2020 |  | December 31, 2019
Commercial |  |  |
Commercial real estate | $ | 3,442,495 |  |  | $ | 3,416,518 |
Commercial and industrial | 1,781,402 |  |  | 1,720,833 |
Commercial construction | 396,518 |  |  | 375,445 |
Total Commercial Loans | 5,620,415 |  |  | 5,512,796 |
Consumer |  |  |
Residential mortgage | 988,816 |  |  | 998,585 |
Home Equity | 544,405 |  |  | 538,348 |
Installment and other consumer | 79,887 |  |  | 79,033 |
Consumer construction | 13,222 |  |  | 8,390 |
Total Consumer Loans | 1,626,330 |  |  | 1,624,356 |
Total Portfolio Loans | 7,246,745 |  |  | 7,137,152 |
Loans held for sale | 7,309 |  |  | 5,256 |
Total Loans(1) | $ | 7,254,054 |  |  | $ | 7,142,408 |

(1) Excludes interest receivable of $22.1 million at both March 31, 2020 and December 31, 2019. Interest receivable is included in other assets in the consolidated balance sheets.
We attempt to limit our exposure to credit risk by diversifying our loan portfolio by segment, geography, collateral and industry and actively managing concentrations. When concentrations exist in certain segments, we mitigate this risk by reviewing the relevant economic indicators and internal risk rating trends and through stress testing of the loans in these segments. Total commercial loans represented 77.6 percent of total portfolio loans at March 31, 2020 and 77.2 percent at December 31, 2019. Within our commercial portfolio, the CRE and Commercial Construction portfolios combined comprised $3.8 billion or 68.3 percent of total commercial loans at March 31, 2020 and $3.8 billion or 68.8 percent of total commercial loans at December 31, 2019 and 53.0 percent of total portfolio loans at March 31, 2020 and 53.1 percent at December 31, 2019. Further segmentation of the CRE and commercial construction portfolios by collateral type reveals no concentration in excess of 13.6 percent of both total CRE and commercial construction loans at March 31, 2020 and 11 percent at December 31, 2019.
We lend primarily in Pennsylvania and the contiguous states of Ohio, New York, West Virginia and Maryland. The majority of our commercial and consumer loans are made to businesses and individuals in this geography, resulting in a concentration. We believe our knowledge and familiarity with customers and conditions locally outweighs this geographic concentration risk. The conditions of the local and regional economies are monitored closely through publicly available data and information supplied by our customers. We also use subscription services for additional geographic and industry specific information. Our CRE and commercial construction portfolios have exposure outside of this geography of 5.4 percent of the combined portfolios and 2.8 percent of total portfolio loans at March 31, 2020. This compares to 5.4 percent of the combined portfolios and 2.9 percent of total portfolio loans at December 31, 2019.
We individually evaluate all substandard and nonaccrual commercial loans that have experienced a forbearance or change in terms agreement, and all substandard consumer and residential mortgage loans that entered into an agreement to modify their existing loan, to determine if they should be designated as troubled debt restructurings, or TDRs.
All TDRs will be reported as such for the remaining life of the loan, unless the restructuring agreement specifies an interest rate equal to or greater than the rate that would be accepted at the time of the restructuring for a new loan with comparable risk and it is fully expected that the remaining principal and interest will be collected according to the restructured agreement. TDRs can be returned to accruing status if the ultimate collectability of all contractual amounts due, according to the restructured agreement, is not in doubt and there is a period of a minimum of six months of satisfactory payment performance by the borrower either immediately before or after the restructuring.
24

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 6. LOANS AND LOANS HELD FOR SALE - continued
The following tables summarize restructured loans as of the dates presented:

| March 31, 2020
(dollars in thousands) | Performing TDRs |  | Nonperforming TDRs |  | Total TDRs
Commercial real estate | $ | 30 |  |  | $ | 28,973 |  |  | $ | 29,003 |
Commercial and industrial | 4,566 |  |  | 4,665 |  |  | 9,231 |
Commercial construction | 3,316 |  |  | — |  |  | 3,316 |
Business banking | 1,524 |  |  | 352 |  |  | 1,876 |
Consumer real estate | 5,749 |  |  | 2,064 |  |  | 7,813 |
Other consumer | 4 |  |  | — |  |  | 4 |
Total(1) | $ | 15,189 |  |  | $ | 36,055 |  |  | $ | 51,243 |

(1) Refer to Note 1, Basis of Presentation for details of reclassification of our portfolio segments related to the adoption of ASU 2016-13 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.

| December 31, 2019
(dollars in thousands) | Performing TDRs |  | Nonperforming TDRs |  | Total TDRs
Commercial real estate | $ | 22,233 |  |  | $ | 6,713 |  |  | $ | 28,946 |
Commercial and industrial | 6,909 |  |  | 695 |  |  | 7,604 |
Commercial construction | 1,425 |  |  | — |  |  | 1,425 |
Residential mortgage | 2,013 |  |  | 822 |  |  | 2,835 |
Home equity | 4,371 |  |  | 678 |  |  | 5,049 |
Installment and other consumer | 9 |  |  | 4 |  |  | 13 |
Total | $ | 36,960 |  |  | $ | 8,912 |  |  | $ | 45,872 |

The significant increase in nonperforming TDRs at March 31, 2020 compared to December 31, 2019 primarily related to a $20.9 million CRE relationship that became a performing TDR in the third quarter of 2019 and then moved to nonperforming in the first quarter of 2020 when the borrower experienced financial deterioration that led to cash flow issues. The relationship was individually assessed at March 31, 2020 resulting in no ACL due to the borrower being current on their payments under the modified terms and the relationship is fully collateralized.
There were no TDRs that returned to accruing status during the three months ended March 31, 2020. There were three TDRs totaling $1.7 million that returned to accruing status during the three months ended March 31, 2019.
25

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 6. LOANS AND LOANS HELD FOR SALE - continued
The following tables present the restructured loans by portfolio segment and by type of concession for the three months ended March 31, 2020 and 2019:

| Three Months Ended March 31, 2020
(dollars in thousands) | Number of Loans |  | Pre-Modification Outstanding Recorded Investment(1) |  | Post-Modification Outstanding Recorded Investment(1) |  | Total Difference in Recorded Investment
Totals by Loan Segment |  |  |  |  |  |  |
Commercial Real Estate |  |  |  |  |  |  |
Principal deferral and maturity date extension | 1 |  |  | $ | 2,210 |  |  | $ | 2,210 |  |  | $ | — |
Total Commercial Real Estate | 1 |  |  | 2,210 |  |  | 2,210 |  |  | — |
Commercial and Industrial |  |  |  |  |  |  |
Principal deferral and maturity date extension | 5 |  |  | 3,780 |  |  | 3,780 |  |  | — |
Total Commercial and Industrial | 5 |  |  | 3,780 |  |  | 3,780 |  |  | — |
Commercial Construction |  |  | — |  |  |  |  |
Maturity date extension | 1 |  |  | 1,891 |  |  | 1,891 |  |  | — |
Total Commercial Construction | 1 |  |  | 1,891 |  |  | 1,891 |  |  | — |
Consumer Real Estate |  |  |  |  |  |  |
Consumer bankruptcy(2) | 6 |  |  | 388 |  |  | 388 |  |  | — |
Maturity date extension and reduction in payment | 1 |  |  | 27 |  |  | 27 |  |  | — |
Total Consumer Real Estate | 7 |  |  | 415 |  |  | 415 |  |  | — |
Totals by Concession Type |  |  |  |  |  |  |
Principal deferral and maturity date extension | 6 |  |  | 5,991 |  |  | 5,991 |  |  | — |
Maturity date extension | 1 |  |  | 1,891 |  |  | 1,891 |  |  | — |
Consumer bankruptcy(2) | 6 |  |  | 388 |  |  | 388 |  |  | — |
Maturity date extension and payment reduction | 1 |  |  | 27 |  |  | 27 |  |  | — |
Total(3) | 14 |  |  | $ | 8,297 |  |  | $ | 8,297 |  |  | $ | — |
(1) Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end. (2) Consumer bankruptcy loans where the debt has been legally discharged through the bankruptcy court and not reaffirmed. (3) Refer to Note 1, Basis of Presentation for details of reclassification of our portfolio segments related to the adoption of ASU 2016-13 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.

26

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 6. LOANS AND LOANS HELD FOR SALE - continued

| Three Months Ended March 31, 2019
(dollars in thousands) | Number of Loans |  | Pre-Modification Outstanding Recorded Investment(1) |  | Post-Modification Outstanding Recorded Investment(1) |  | Total Difference in Recorded Investment
Totals by Loan Segment |  |  |  |  |  |  |
Commercial and Industrial |  |  |  |  |  |  |
Maturity date extension and interest rate reduction | 1 |  |  | $ | 5,201 |  |  | $ | 5,201 |  |  | $ | — |
Principal deferral and maturity date extension | — |  |  | — |  |  | — |  |  | — |
Total Commercial and Industrial | 1 |  |  | 5,201 |  |  | 5,201 |  |  | — |
Residential Mortgage |  |  |  |  |  |  |
Consumer bankruptcy(2) | 1 |  |  | 49 |  |  | 49 |  |  | — |
Total Residential Mortgage | 1 |  |  | 49 |  |  | 49 |  |  | — |
Home Equity |  |  |  |  |  |  |
Consumer bankruptcy(2) | 7 |  |  | 191 |  |  | 168 |  |  | (23 | )
Interest rate reduction | 1 |  |  | 81 |  |  | 81 |  |  | — |
Maturity date extension and reduction in payment | — |  |  | — |  |  | — |  |  | — |
Total Home Equity | 8 |  |  | 272 |  |  | 249 |  |  | (23 | )
Totals by Concession Type |  |  |  |  |  |  |
Maturity date extension and interest rate reduction | 1 |  |  | 5,201 |  |  | 5,201 |  |  | — |
Consumer bankruptcy(2) | 8 |  |  | 240 |  |  | 217 |  |  | (23 | )
Interest rate reduction | 1 |  |  | 81 |  |  | 81 |  |  | — |
Total | 10 |  |  | $ | 5,522 |  |  | $ | 5,499 |  |  | $ | (23 | )
(1) Excludes loans that were fully paid-off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end. (2) Consumer bankruptcy loans where the debt has been legally discharged through the bankruptcy court and not reaffirmed.

In response to the COVID-19 pandemic and its economic impact to our customers, we implemented a short-term modification program that complies with the Coronavirus Aid, Relief, and Economic Security, or CARES Act to provide temporary payment relief to those borrowers directly impacted by COVID-19 who were not more than 30 days past due as of December 31, 2019. This program allows for a deferral of payments for 90 days, up to a maximum of 180 days for our commercial customers. The deferred payments along with interest accrued during the deferral period are due and payable on the maturity date. For our consumer customers interest does not accrue during the deferral period and the maturity date is extended by the length of the deferral period. Under the applicable guidance, none of these loans were considered restructured as of March 31, 2020.
As of March 31, 2020, we had 20 commitments to lend an additional $2.3 million on TDRs. Defaulted TDRs are defined as loans having a payment default of 90 days or more after the restructuring takes place. There were 11 TDRs that defaulted during the three months ended March 31, 2020 totaling $21.1 million and no TDRs that defaulted during the three months ended March 31, 2019 that were restructured within the last 12 months prior to defaulting. The large increase in defaulted TDRs is related to one CRE customer with five notes totaling $20.9 million discussed above.
27

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 6. LOANS AND LOANS HELD FOR SALE - continued
The following table is a summary of nonperforming assets as of the dates presented:

| Nonperforming Assets
(dollars in thousands) | March 31, 2020 |  |  | December 31, 2019 |
Nonperforming Assets |  |  |  |  |
Nonaccrual loans |  | $ | 37,744 |  |  |  | $ | 45,145 |
Nonaccrual TDRs |  | 36,055 |  |  |  | 8,912 |
Total Nonaccrual Loans |  | 73,799 |  |  |  | 54,057 |
OREO |  | 3,389 |  |  |  | 3,525 |
Total Nonperforming Assets |  | $ | 77,188 |  |  |  | $ | 57,582 |

The significant increase in nonperforming TDRs primarily related to a $20.9 million CRE relationship discussed above.
28

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 7. ALLOWANCE FOR CREDIT LOSSES
We maintain an ACL at a level determined to be adequate to absorb estimated expected credit losses within the loan portfolio over the contractual life of an instrument that considers our historical loss experience, current conditions and forecasts of future economic conditions as of the balance sheet date. We develop and document a systematic ACL methodology based on the following portfolio segments: 1) Construction, 2) Commercial Real Estate, or CRE, 3) Commercial and Industrial, or C&I, 4) Business Banking, 5) Consumer Real Estate and 6) Other Consumer.
The following are key risks within each portfolio segment:
CRE—Loans secured by commercial purpose real estate, including both owner-occupied properties and investment properties for various purposes such as hotels, retail, multifamily, and health care. Operations of the individual projects and global cash flows of the debtors are the primary sources of repayment for these loans. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the collateral type and the business prospects of the lessee, if the project is not owner-occupied.
C&I—Loans made to operating companies or manufacturers for the purpose of production, operating capacity, accounts receivable, inventory or equipment financing. Cash flow from the operations of the company is the primary source of repayment for these loans. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the industry of the company. Collateral for these types of loans often does not have sufficient value in a distressed or liquidation scenario to satisfy the outstanding debt.
Commercial Construction—Loans made to finance construction of buildings or other structures, as well as to finance the acquisition and development of raw land for various purposes. While the risk of these loans is generally confined to the construction period, if there are problems, the project may not be completed, and as such, may not provide sufficient cash flow on its own to service the debt or have sufficient value in a liquidation to cover the outstanding principal. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the type of project and the experience and resources of the developer.
Business Banking—Commercial loans made to small businesses that are standard, non-complex products evaluated through a streamlined credit approval process that has been designed to maximize efficiency while maintaining high credit quality standards that meet small business market customers’ needs. The business banking portfolio is monitored by utilizing a standard and closely managed process focusing on behavioral and performance criteria. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the collateral type and business.
Consumer Real Estate—Loans secured by first and second liens such as home equity loans, home equity lines of credit and 1-4 family residential mortgages, including purchase money mortgages. The primary source of repayment for these loans is the income and assets of the borrower. The condition of the local economy, in particular the unemployment rate, is an important indicator of risk for this segment. The state of the local housing market can also have a significant impact on this segment because low demand and/or declining home values can limit the ability of borrowers to sell a property and satisfy the debt.
Other Consumer—Loans made to individuals that may be secured by assets other than 1-4 family residences, as well as unsecured loans. This segment includes auto loans, unsecured loans and lines and credit cards. The primary source of repayment for these loans is the income and assets of the borrower. The condition of the local economy, in particular the unemployment rate, is an important indicator of risk for this segment. The value of the collateral, if there is any, is less likely to be a source of repayment due to less certain collateral values.
Management monitors various credit quality indicators for the commercial, business banking and consumer loan portfolios, including changes in risk ratings, nonperforming status and delinquency on a monthly basis.
We monitor the commercial loan portfolio through an internal risk rating system. Loan risk ratings are assigned based upon the creditworthiness of the borrower and are reviewed on an ongoing basis according to our internal policies. Loans within the pass rating generally have a lower risk of loss than loans risk rated as special mention or substandard.
Our risk ratings are consistent with regulatory guidance and are as follows:
Pass—The loan is currently performing and is of high quality.
29

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 7. ALLOWANCE FOR CREDIT LOSSES – continued
Special Mention—A special mention loan has potential weaknesses that warrant management’s close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects or in the strength of our credit position at some future date.
Substandard—A substandard loan is not adequately protected by the net worth and/or paying capacity of the borrower or by the collateral pledged, if any. Substandard loans have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. These loans are characterized by the distinct possibility that we will sustain some loss if the deficiencies are not corrected.
Doubtful—Loans classified doubtful have all the weaknesses inherent in those classified substandard with the added characteristic that the weaknesses make collection or liquidation in full, on the basis of currently known facts, conditions, and values, highly questionable and improbable.
The following table presents loan balances by year of origination and internally assigned risk rating for our portfolio segments as of March 31, 2020:

| Risk Rating
(dollars in thousands) | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 and Prior | Revolving | Revolving-Term | Total
Commercial Real Estate |  |  |  |  |  |  |  |  |
Pass | $ | 169,367 |  | $ | 483,699 |  | $ | 452,024 |  | $ | 359,553 |  | $ | 416,420 |  | $ | 882,326 |  | $ | 59,032 |  | — |  | $ | 2,822,421 |
Special Mention | — |  | 3,236 |  | 187 |  | 11,591 |  | 10,005 |  | 26,575 |  | 850 |  | — |  | 52,444 |
Substandard | — |  | — |  | 1,462 |  | — |  | 25,285 |  | 50,348 |  | 3,008 |  | 21 |  | 80,124 |
Total Commercial Real Estate | 169,367 |  | 486,935 |  | 453,673 |  | 371,144 |  | 451,710 |  | 959,249 |  | 62,890 |  | 21 |  | 2,954,989 |
Commercial and Industrial |  |  |  |  |  |  |  |  |
Pass | 75,969 |  | 240,261 |  | 165,631 |  | 103,537 |  | 73,798 |  | 282,138 |  | 486,045 |  | — |  | 1,427,379 |
Special Mention | — |  | 6,239 |  | 3,525 |  | 947 |  | 1,883 |  | 9,437 |  | 31,890 |  | — |  | 53,921 |
Substandard | — |  | 5,666 |  | 2,301 |  | 3,785 |  | 1,621 |  | 12,232 |  | 17,316 |  | — |  | 42,921 |
Total Commercial and Industrial | 75,969 |  | 252,166 |  | 171,457 |  | 108,269 |  | 77,302 |  | 303,807 |  | 535,251 |  | — |  | 1,524,221 |
Commercial Construction |  |  |  |  |  |  |  |  |
Pass | 23,004 |  | 179,956 |  | 117,527 |  | 17,122 |  | 18,986 |  | 11,586 |  | 11,992 |  | — |  | 380,173 |
Special Mention | — |  | — |  | — |  | — |  | — |  | 5,117 |  | 91 |  | — |  | 5,208 |
Substandard | — |  | — |  | — |  | 1,041 |  | — |  | 3,780 |  | — |  | — |  | 4,821 |
Total Commercial Construction | 23,004 |  | 179,956 |  | 117,527 |  | 18,163 |  | 18,986 |  | 20,483 |  | 12,083 |  | — |  | 390,202 |
Business Banking |  |  |  |  |  |  |  |  |
Pass | 40,952 |  | 181,242 |  | 148,419 |  | 103,027 |  | 89,925 |  | 327,333 |  | 125,800 |  | — |  | 1,016,698 |
Special Mention | — |  | 62 |  | 1,496 |  | 1,775 |  | 1,181 |  | 7,902 |  | 737 |  | — |  | 13,153 |
Substandard | — |  | 382 |  | 3,111 |  | 3,646 |  | 4,006 |  | 27,803 |  | 1,665 |  | — |  | 40,613 |
Total Business Banking | 40,952 |  | 181,686 |  | 153,026 |  | 108,448 |  | 95,112 |  | 363,038 |  | 128,202 |  | — |  | 1,070,464 |
Consumer Real Estate |  |  |  |  |  |  |  |  |
Pass | 33,737 |  | 149,942 |  | 86,463 |  | 83,402 |  | 92,013 |  | 316,169 |  | 432,274 |  | 20,966 |  | 1,214,966 |
Special Mention | — |  | — |  | — |  | — |  | 798 |  | 304 |  | — |  | — |  | 1,102 |
Substandard | — |  | 190 |  | 71 |  | 537 |  | 1,103 |  | 7,410 |  | 305 |  | 1,385 |  | 11,001 |
Total Consumer Real Estate | 33,737 |  | 150,132 |  | 86,534 |  | 83,939 |  | 93,914 |  | 323,883 |  | 432,579 |  | 22,351 |  | 1,227,069 |
Other consumer |  |  |  |  |  |  |  |  |
Pass | 8,706 |  | 9,522 |  | 10,670 |  | 6,474 |  | 5,088 |  | 3,365 |  | 28,156 |  | 773 |  | 72,754 |
Special Mention | — |  | — |  | — |  | — |  | — |  | — |  | — |  | — |  | — |
Substandard | — |  | 488 |  | 132 |  | 132 |  | 594 |  | 4,252 |  | 322 |  | 1,126 |  | 7,046 |
Total Other Consumer | 8,706 |  | 10,010 |  | 10,802 |  | 6,606 |  | 5,682 |  | 7,617 |  | 28,478 |  | 1,899 |  | 79,800 |
Total Loan Balance | $ | 351,735 |  | $ | 1,260,885 |  | $ | 993,019 |  | $ | 696,569 |  | $ | 742,706 |  | $ | 1,978,077 |  | $ | 1,199,483 |  | $ | 24,271 |  | $ | 7,246,745 |

We monitor the delinquent status of the commercial and consumer portfolios on a monthly basis. Loans are considered nonperforming when interest and principal are 90 days or more past due or management has determined that a material deterioration in the borrower’s financial condition exists. The risk of loss is generally highest for nonperforming loans.
30

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 7. ALLOWANCE FOR CREDIT LOSSES – continued
The following table presents loan balances by year of origination and performing and nonperforming status for our portfolio segments as of March 31, 2020:

(dollars in thousands) | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 and Prior | Revolving | Revolving-Term | Total
Commercial Real Estate |  |  |  |  |  |  |  |  |
Performing | $ | 169,367 |  | $ | 486,935 |  | $ | 453,673 |  | $ | 371,144 |  | $ | 431,919 |  | $ | 935,536 |  | $ | 59,882 |  | $ | — |  | $ | 2,908,456 |
Nonperforming | — |  | — |  | — |  | — |  | 19,791 |  | 23,713 |  | 3,008 |  | 21 |  | 46,533 |
Total Commercial Real Estate | 169,367 |  | 486,935 |  | 453,673 |  | 371,144 |  | 451,710 |  | 959,249 |  | 62,890 |  | 21 |  | 2,954,989 |
Commercial and Industrial |  |  |  |  |  |  |  |  |
Performing | 75,969 |  | 252,166 |  | 171,093 |  | 108,269 |  | 76,593 |  | 303,745 |  | 531,881 |  | — |  | 1,519,716 |
Nonperforming | — |  | — |  | 364 |  | — |  | 709 |  | 62 |  | 3,370 |  | — |  | 4,505 |
Total Commercial and Industrial | 75,969 |  | 252,166 |  | 171,457 |  | 108,269 |  | 77,302 |  | 303,807 |  | 535,251 |  | — |  | 1,524,221 |
Commercial Construction |  |  |  |  |  |  |  |  |
Performing | 23,004 |  | 179,956 |  | 117,527 |  | 18,055 |  | 18,986 |  | 20,020 |  | 12,083 |  | — |  | 389,631 |
Nonperforming | — |  | — |  | — |  | 108 |  | — |  | 463 |  | — |  | — |  | 571 |
Total Commercial Construction | 23,004 |  | 179,956 |  | 117,527 |  | 18,163 |  | 18,986 |  | 20,483 |  | 12,083 |  | — |  | 390,202 |
Business Banking |  |  |  |  |  |  |  |  |
Performing | 40,952 |  | 181,576 |  | 151,933 |  | 107,176 |  | 94,230 |  | 355,259 |  | 128,022 |  | — |  | 1,059,148 |
Nonperforming | — |  | 110 |  | 1,093 |  | 1,272 |  | 882 |  | 7,779 |  | 180 |  | — |  | 11,316 |
Total Business Banking | 40,952 |  | 181,686 |  | 153,026 |  | 108,448 |  | 95,112 |  | 363,038 |  | 128,202 |  | — |  | 1,070,464 |
Consumer Real Estate |  |  |  |  |  |  |  |  |
Performing | 33,737 |  | 149,942 |  | 86,401 |  | 83,526 |  | 90,151 |  | 318,926 |  | 432,403 |  | 21,367 |  | 1,216,453 |
Nonperforming | — |  | 190 |  | 133 |  | 413 |  | 3,763 |  | 4,957 |  | 176 |  | 984 |  | 10,616 |
Total Consumer Real Estate | 33,737 |  | 150,132 |  | 86,534 |  | 83,939 |  | 93,914 |  | 323,883 |  | 432,579 |  | 22,351 |  | 1,227,069 |
Other Consumer |  |  |  |  |  |  |  |  |
Performing | 8,706 |  | 10,010 |  | 10,802 |  | 6,606 |  | 5,682 |  | 7,359 |  | 28,478 |  | 1,899 |  | 79,542 |
Nonperforming | — |  | — |  | — |  | — |  | — |  | 258 |  | — |  | — |  | 258 |
Total Other Consumer | 8,706 |  | 10,010 |  | 10,802 |  | 6,606 |  | 5,682 |  | 7,617 |  | 28,478 |  | 1,899 |  | 79,800 |
Performing | 351,735 |  | 1,260,585 |  | 991,429 |  | 694,776 |  | 717,561 |  | 1,940,845 |  | 1,192,749 |  | 23,266 |  | 7,172,946 |
Nonperforming | — |  | 300 |  | 1,590 |  | 1,793 |  | 25,145 |  | 37,232 |  | 6,734 |  | 1,005 |  | 73,799 |
Total Loan Balance | $ | 351,735 |  | $ | 1,260,885 |  | $ | 993,019 |  | $ | 696,569 |  | $ | 742,706 |  | $ | 1,978,077 |  | $ | 1,199,483 |  | $ | 24,271 |  | $ | 7,246,745 |

The following tables present the age analysis of past due loans segregated by class of loans as of the dates presented:

| March 31, 2020
(dollars in thousands) | Current |  |  | 30-59 Days Past Due |  |  | 60-89 Days Past Due |  |  | 90 Days Past Due(1) |  |  | Non - performing |  |  | Total Past Due Loans |  |  | Total Loans |
Commercial real estate | $ | 2,901,375 |  |  | $ | 6,381 |  |  | $ | — |  |  | $ | 700 |  |  | $ | 46,533 |  |  | $ | 53,614 |  |  | $ | 2,954,989 |
Commercial and industrial | 1,516,639 |  |  | 463 |  |  | — |  |  | 2,615 |  |  | 4,505 |  |  | 7,582 |  |  | 1,524,221 |
Commercial construction | 388,122 |  |  | 576 |  |  | — |  |  | 933 |  |  | 571 |  |  | 2,080 |  |  | 390,202 |
Business banking | 1,048,241 |  |  | 6,758 |  |  | 3,381 |  |  | 768 |  |  | 11,316 |  |  | 22,223 |  |  | 1,070,464 |
Consumer real estate | 1,211,865 |  |  | 3,859 |  |  | 646 |  |  | 83 |  |  | 10,616 |  |  | 15,203 |  |  | 1,227,069 |
Other consumer | 79,083 |  |  | 174 |  |  | 91 |  |  | 195 |  |  | 258 |  |  | 717 |  |  | 79,800 |
Total | $ | 7,145,326 |  |  | $ | 18,211 |  |  | $ | 4,117 |  |  | $ | 5,294 |  |  | $ | 73,799 |  |  | $ | 101,419 |  |  | $ | 7,246,745 |

(1) Refer to Note 1, Basis of Presentation for details of reclassification of our portfolio segments related to the adoption of ASU 2016-13 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instrument.
31

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 7. ALLOWANCE FOR CREDIT LOSSES – continued

| December 31, 2019
(dollars in thousands) | Current |  |  | 30-59 Days Past Due |  |  | 60-89 Days Past Due |  |  | 90 Days Past Due(1) |  |  | Non - performing |  |  | Total Past Due Loans |  |  | Total Loans |
Commercial real estate | $ | 3,025,505 |  |  | $ | 7,749 |  |  | $ | 71 |  |  | $ | 911 |  |  | $ | 25,356 |  |  | $ | 34,087 |  |  | $ | 3,059,592 |
Commercial and industrial | 1,466,460 |  |  | 126 |  |  | 1,589 |  |  | 1,443 |  |  | 10,911 |  |  | 14,069 |  |  | 1,480,529 |
Commercial construction | 367,204 |  |  | 956 |  |  | 1,163 |  |  | — |  |  | 737 |  |  | 2,856 |  |  | 370,060 |
Business banking | 830,735 |  |  | 5,093 |  |  | 1,099 |  |  | — |  |  | 9,863 |  |  | 16,055 |  |  | 846,790 |
Consumer real estate | 1,283,591 |  |  | 2,620 |  |  | 1,758 |  |  | 1,175 |  |  | 6,063 |  |  | 11,616 |  |  | 1,295,207 |
Other consumer | 81,866 |  |  | 1,448 |  |  | 305 |  |  | 228 |  |  | 1,127 |  |  | 3,108 |  |  | 84,974 |
Total | $ | 7,055,361 |  |  | $ | 17,992 |  |  | $ | 5,985 |  |  | $ | 3,757 |  |  | $ | 54,057 |  |  | $ | 81,791 |  |  | $ | 7,137,152 |

(1)Represents acquired loans that were recorded at fair value at the acquisition date and remain performing at March 31, 2020 and December 31, 2019.
The following table presents loans on nonaccrual status and loans past due 90 days or more and still accruing by class of loan:

| As or for the Three Months Ended March 31, 2020
(dollars in thousands) | Beginning of Period Nonaccrual |  | End of Period Nonaccrual |  | Nonaccrual With No Related Allowance |  | Past Due 90+ Days Still Accruing |  | Interest Income Recognized on Nonaccrual
Commercial real estate |  | $25,356 |  |  | $ | 46,533 |  |  |  | $39,454 |  |  | $ | 700 |  |  |  | $684 |
Commercial and industrial | 10,911 |  |  | 4,505 |  |  | 4,054 |  |  | 2,615 |  |  | 64 |
Commercial construction | 737 |  |  | 571 |  |  | 285 |  |  | 933 |  |  | — |
Business banking | 9,863 |  |  | 11,316 |  |  | 2,363 |  |  | 768 |  |  | 58 |
Consumer real estate | 6,063 |  |  | 10,616 |  |  | 398 |  |  | 83 |  |  | 47 |
Other consumer | 1,127 |  |  | 258 |  |  | — |  |  | 195 |  |  | 28 |
Total |  | $54,057 |  |  |  | $73,799 |  |  |  | $46,554 |  |  | $ | 5,294 |  |  |  | $881 |

The following table presents collateral-dependent loans by class of loan:

| March 31, 2020
| Type of Collateral
(dollars in thousands) | Real Estate |  | Blanket Lien |  | Investment/Cash |  | Other
Commercial real estate |  | $51,630 |  |  |  | $— |  |  |  | $— |  |  |  | $— |
Commercial and industrial | 4,686 |  |  | 4,545 |  |  | 40 |  |  | — |
Commercial construction | 3,602 |  |  | — |  |  | — |  |  | — |
Business banking | 2,322 |  |  | 876 |  |  | — |  |  | 689 |
Consumer real estate | — |  |  | — |  |  | — |  |  | — |
Other consumer | 398 |  |  | — |  |  | — |  |  | — |
Total |  | $62,638 |  |  |  | $5,421 |  |  |  | $40 |  |  |  | $689 |

32

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 7. ALLOWANCE FOR CREDIT LOSSES – continued
The following table presents activity in the ACL for the three months ended March 31, 2020:

| Three Months Ended March 31, 2020
(dollars in thousands) | Commercial Real Estate |  | Commercial and Industrial |  | Commercial Construction |  | Business Banking(1) |  | Consumer Real Estate |  | Other Consumer |  | Total Loans
Allowance for credit losses on loans: |  |  |  |  |  |  |  |  |  |  |  |  |
Balance at beginning of period | $ | 30,577 |  |  | $ | 15,681 |  |  | $ | 7,900 |  |  | $ | — |  |  | $ | 6,337 |  |  | $ | 1,729 |  |  | $ | 62,224 |
Impact of CECL adoption | 4,810 |  |  | 7,853 |  |  | (3,376 | ) |  | 12,898 |  |  | 4,525 |  |  | 642 |  |  | 27,352 |
Provision for credit losses on loans | 7,639 |  |  | 6,196 |  |  | 2,309 |  |  | 1,194 |  |  | 472 |  |  | 620 |  |  | 18,430 |
Charge-offs | (442 | ) |  | (9,879 | ) |  | (229 | ) |  | (460 | ) |  | (172 | ) |  | (248 | ) |  | (11,430 | )
Recoveries | 27 |  |  | 19 |  |  | 2 |  |  | 74 |  |  | 38 |  |  | 114 |  |  | 274 |
Net (Charge-offs)/Recoveries | (415 | ) |  | (9,860 | ) |  | (227 | ) |  | (386 | ) |  | (134 | ) |  | (134 | ) |  | (11,156 | )
Balance at End of Period | $ | 42,611 |  |  | $ | 19,870 |  |  | $ | 6,606 |  |  | $ | 13,706 |  |  | $ | 11,200 |  |  | $ | 2,857 |  |  | $ | 96,850 |

(1) In connection with our adoption of ASU 2016-13, we made changes to our loan portfolio segments to align with the methodology applied in determining the allowance under CECL. Our new segmentation breaks out business banking loans from our other loan segments: CRE, C&I , commercial construction, consumer real estate and other consumer. The business banking allowance balance at the beginning of period is included in the other segments and reclassified to business banking through the impact of CECL adoption line.
The adoption of ASU 2016-13 resulted in an increase to our ACL of $27.4 million on January 1, 2020. The increase included $8.2 million for S&T legacy loans and $9.3 million for acquired loans from the DNB merger. We also recorded a day one adjustment of $9.9 million primarily related to a C&I relationship that was charged off in the first quarter of 2020. We obtained information on the relationship subsequent to filing our December 31, 2019 10-K, but before the end of the first quarter of 2020. The updated information supported a loss existed at January 1, 2020. The significant increase in the provision for credit losses during the three months ended March 31, 2020 was mainly due to the COVID-19 pandemic. We added approximately $14.9 million to the ACL in the first quarter of 2020 related to qualitative factors. This included $11.2 million for a revised economic forecast and the impact of that forecast on certain loan portfolios due to the COVID-19 pandemic. Changes in current conditions resulted in an additional $3.7 million increase in the ACL.
Prior to the adoption of ASU 326 on January 1, 2020, we calculated our allowance for loan losses using an incurred loan loss methodology. The following tables are disclosures related to the allowance for loan losses in prior periods.
The following table presents the recorded investment in commercial loan classes by internally assigned risk ratings as of December 31, 2019:

| December 31, 2019
(dollars in thousands) | Commercial Real Estate | % of Total |  | Commercial and Industrial | % of Total |  | Commercial Construction | % of Total |  | Total | % of Total
Pass | $ | 3,270,437 |  | 95.7 | % |  | $ | 1,636,314 |  | 93.4 | % |  | $ | 347,324 |  | 92.5 | % |  | $ | 5,254,076 |  | 95.3 | %
Special mention | 57,285 |  | 1.7 | % |  | 36,484 |  | 1.7 | % |  | 10,109 |  | 2.7 | % |  | 103,878 |  | 1.9 | %
Substandard | 86,772 |  | 2.5 | % |  | 47,980 |  | 4.9 | % |  | 17,899 |  | 4.8 | % |  | 152,651 |  | 2.8 | %
Doubtful | 2,023 |  | — | % |  | 55 |  | — | % |  | 133 |  | — | % |  | 2,191 |  | — | %
Total | $ | 3,416,518 |  | 100.0 | % |  | $ | 1,720,833 |  | 100.0 | % |  | $ | 375,445 |  | 100.0 | % |  | $ | 5,512,796 |  | 100.0 | %

The following table presents the recorded investment in consumer loan classes by performing and nonperforming status as of December 31, 2019:

| December 31, 2019
(dollars in thousands) | Residential Mortgage | % of Total |  | Home Equity | % of Total |  | Installment and Other Consumer | % of Total |  | Consumer Construction | % of Total |  | Total | % of Total
Performing | $ | 991,066 |  | 99.2 | % |  | $ | 535,709 |  | 99.5 | % |  | $ | 78,993 |  | 99.9 | % |  | $ | 8,390 |  | 100.0 | % |  | $ | 1,614,158 |  | 99.4 | %
Nonperforming | 7,519 |  | 0.8 | % |  | 2,639 |  | 0.5 | % |  | 40 |  | 0.1 | % |  | — |  | — | % |  | 10,198 |  | 0.6 | %
Total | $ | 998,585 |  | 100.0 | % |  | $ | 538,348 |  | 100.0 | % |  | $ | 79,033 |  | 100.0 | % |  | $ | 8,390 |  | 100.0 | % |  | $ | 1,624,356 |  | 100.0 | %

The following table presents investments in loans considered to be impaired and related information on those impaired loans as of December 31, 2019:
33

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 7. ALLOWANCE FOR CREDIT LOSSES – continued

| December 31, 2019
(dollars in thousands) | Recorded Investment |  | Unpaid Principal Balance |  | Related Allowance
With a related allowance recorded: |  |  |  |  |
Commercial real estate | $ | 13,011 |  |  | $ | 14,322 |  |  | $ | 2,023 |
Commercial and industrial | 10,001 |  |  | 10,001 |  |  | 55 |
Commercial construction | 489 |  |  | 489 |  |  | 113 |
Consumer real estate | — |  |  | — |  |  | — |
Other consumer | 9 |  |  | 9 |  |  | 9 |
Total with a Related Allowance Recorded | 23,510 |  |  | 24,821 |  |  | 2,200 |
Without a related allowance recorded: |  |  |  |  |
Commercial real estate | 34,909 |  |  | 40,201 |  |  | — |
Commercial and industrial | 7,605 |  |  | 10,358 |  |  | — |
Commercial construction | 1,425 |  |  | 2,935 |  |  | — |
Consumer real estate | 7,884 |  |  | 8,445 |  |  | — |
Other consumer | 4 |  |  | 11 |  |  | — |
Total without a Related Allowance Recorded | 51,827 |  |  | 61,950 |  |  | — |
Total: |  |  |  |  |
Commercial real estate | 47,920 |  |  | 54,523 |  |  | 2,023 |
Commercial and industrial | 17,606 |  |  | 20,359 |  |  | 55 |
Commercial construction | 1,914 |  |  | 3,424 |  |  | 113 |
Consumer real estate | 7,884 |  |  | 8,445 |  |  | — |
Other consumer | 13 |  |  | 20 |  |  | 9 |
Total | $ | 75,337 |  |  | $ | 86,771 |  |  | $ | 2,200 |

34

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 7. ALLOWANCE FOR CREDIT LOSSES – continued
The following table presents average recorded investment and interest income recognized on impaired loans for the three months ended March 31, 2019:

| Three months ended
| March 31, 2019
(dollars in thousands) | Average Recorded Investment |  | Interest Income Recognized
With a related allowance recorded: |  |  |
Commercial real estate | $ | 15,107 |  |  | $ | 144 |
Commercial and industrial | 12,780 |  |  | 209 |
Commercial construction | 2,319 |  |  | 140 |
Consumer real estate | 8,846 |  |  | 417 |
Other consumer | 4 |  |  | — |
Total with a Related Allowance Recorded | 39,056 |  |  | 910 |
Without a related allowance recorded: |  |  |
Commercial real estate | 12,983 |  |  | 400 |
Commercial and industrial | 980 |  |  | 35 |
Commercial construction | 489 |  |  | — |
Consumer real estate | 14 |  |  | 1 |
Other consumer | 10 |  |  | 1 |
Total without a Related Allowance Recorded | 14,476 |  |  | 437 |
Total: |  |  |
Commercial real estate | 28,090 |  |  | 544 |
Commercial and industrial | 13,760 |  |  | 244 |
Commercial construction | 2,808 |  |  | 140 |
Consumer real estate | 8,860 |  |  | 418 |
Other consumer | 14 |  |  | 1 |
Total | $ | 53,532 |  |  | $ | 1,347 |

The following table details activity in the allowance for loan losses for the three months ended March 31, 2019:

|  |  | Three Months Ended March 31, 2019
(dollars in thousands) |  |  | Commercial Real Estate |  | Commercial and Industrial |  | Commercial Construction |  | Consumer Real Estate |  | Other Consumer |  | Total Loans
Balance at beginning of period |  |  | $ | 33,707 |  |  | $ | 11,596 |  |  | $ | 7,983 |  |  | $ | 6,187 |  |  | $ | 1,494 |  |  | $ | 6,996 |
Charge-offs |  |  | (1 | ) |  | (5,477 | ) |  | — |  |  | (162 | ) |  | (425 | ) |  | (6,023 | )
Recoveries |  |  | 122 |  |  | 417 |  |  | — |  |  | 148 |  |  | 169 |  |  | 787 |
Net (Charge-offs)/Recoveries |  |  | 121 |  |  | (5,060 | ) |  | — |  |  | (14 | ) |  | (256 | ) |  | (5,236 | )
Provision for credit losses |  |  | 1,075 |  |  | 5,460 |  |  | (1,226 | ) |  | 5 |  |  | 249 |  |  | 5,649 |
Balance at End of Period |  |  | $ | 34,903 |  |  | $ | 11,996 |  |  | $ | 6,757 |  |  | $ | 6,178 |  |  | $ | 1,487 |  |  | $ | 61,409 |

The following tables present the allowance for loan losses and recorded investments in loans by category as of December 31,2019:

| December 31, 2019
| Allowance for Loan Losses |  | Portfolio Loans
(dollars in thousands) | Individually Evaluated for Impairment |  |  | Collectively Evaluated for Impairment |  |  | Total |  |  | Individually Evaluated for Impairment |  |  | Collectively Evaluated for Impairment |  |  | Total |
Commercial real estate | $ | 2,023 |  |  | $ | 28,554 |  |  | $ | 30,577 |  |  | $ | 47,920 |  |  | $ | 3,368,598 |  |  | $ | 3,416,518 |
Commercial and industrial | 55 |  |  | 15,626 |  |  | 15,681 |  |  | 17,606 |  |  | 1,703,227 |  |  | 1,720,833 |
Commercial construction | 113 |  |  | 7,787 |  |  | 7,900 |  |  | 1,914 |  |  | 373,531 |  |  | 375,445 |
Consumer real estate | — |  |  | 6,337 |  |  | 6,337 |  |  | 7,884 |  |  | 1,537,439 |  |  | 1,545,323 |
Other consumer | 9 |  |  | 1,720 |  |  | 1,729 |  |  | 13 |  |  | 79,020 |  |  | 79,033 |
Total | $ | 2,200 |  |  | $ | 60,024 |  |  | $ | 62,224 |  |  | $ | 75,337 |  |  | $ | 7,061,815 |  |  | $ | 7,137,152 |

35

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 8. DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES
Interest Rate Swaps
In accordance with applicable accounting guidance for derivatives and hedging, all derivatives are recognized as either assets or liabilities on the balance sheet at fair value. Interest rate swaps are contracts in which a series of interest rate flows (fixed and variable) are exchanged over a prescribed period. The notional amounts on which the interest payments are based are not exchanged. These derivative positions relate to transactions in which we enter into an interest rate swap with a commercial customer while at the same time entering into an offsetting interest rate swap with another financial institution. In connection with each transaction, we agree to pay interest to the customer on a notional amount at a variable interest rate and receive interest from the customer on the same notional amount at a fixed rate. At the same time, we agree to pay another financial institution the same fixed interest rate on the same notional amount and receive the same variable interest rate on the same notional amount. The transaction allows our customer to effectively convert a variable rate loan to a fixed rate loan with us receiving a variable rate. These agreements could have floors or caps on the contracted interest rates.
Pursuant to our agreements with various financial institutions, we may receive collateral or may be required to post collateral based upon mark-to-market positions. Beyond unsecured threshold levels, collateral in the form of cash or securities may be made available to counterparties of interest rate swap transactions. Based upon our current positions and related future collateral requirements relating to them, we believe any effect on our cash flow or liquidity position to be immaterial.
Derivatives contain an element of credit risk, the possibility that we will incur a loss because a counterparty, which may be a financial institution or a customer, fails to meet its contractual obligations. All derivative contracts with financial institutions may be executed only with counterparties approved by our Asset and Liability Committee, or ALCO, and derivatives with customers may only be executed with customers within credit exposure limits approved by our Senior Loan Committee. Interest rate swaps are considered derivatives but are not accounted for using hedge accounting. As such, changes in the estimated fair value of the derivatives are recorded in current earnings and included in other noninterest income in the Consolidated Statements of Comprehensive Income.
Interest Rate Lock Commitments and Forward Sale Contracts
In the normal course of business, we sell originated mortgage loans into the secondary mortgage loan market. We also offer interest rate lock commitments to potential borrowers. The commitments are generally for a period of 60 days and guarantee a specified interest rate for a loan if underwriting standards are met, but the commitment does not obligate the potential borrower to close on the loan. Accordingly, some commitments expire prior to becoming loans. We may encounter pricing risks if interest rates increase significantly before the loan can be closed and sold. We may utilize forward sale contracts in order to mitigate this pricing risk. Whenever a customer desires these products, a mortgage originator quotes a secondary market rate guaranteed for that day by the investor. The rate lock is executed between the mortgagee and us and in turn a forward sale contract may be executed between us and the investor. Both the rate lock commitment and the corresponding forward sale contract for each customer are considered derivatives but are not accounted for using hedge accounting. As such, changes in the estimated fair value of the derivatives during the commitment period are recorded in current earnings and included in mortgage banking in the Consolidated Statements of Comprehensive Income.
36

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 8. DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES – continued
The following table indicates the amounts representing the value of derivative assets and derivative liabilities as of the dates presented:

| Derivatives (included in Other Assets) |  | Derivatives (included in Other Liabilities)
(dollars in thousands) | March 31, 2020 |  |  | December 31, 2019 |  |  | March 31, 2020 |  |  | December 31, 2019 |
Derivatives not Designated as Hedging Instruments: |  |  |  |  |  |  |  |  |  |  |
Interest Rate Swap Contracts - Commercial Loans |  |  |  |  |  |  |  |  |  |  |
Fair value |  | $ | 88,135 |  |  |  | $ | 25,647 |  |  |  | $ | 87,989 |  |  |  | $ | 25,615 |
Notional amount |  | 918,481 |  |  |  | 740,762 |  |  |  | 918,481 |  |  |  | 740,762 |
Collateral posted |  | — |  |  |  | — |  |  |  | 86,720 |  |  |  | 26,127 |
Interest Rate Lock Commitments - Mortgage Loans |  |  |  |  |  |  |  |  |  |  |
Fair value |  | 2,927 |  |  |  | 321 |  |  |  | — |  |  |  | — |
Notional amount |  | 86,674 |  |  |  | 9,829 |  |  |  | — |  |  |  | — |
Forward Sale Contracts - Mortgage Loans |  |  |  |  |  |  |  |  |  |  |
Fair value |  | — |  |  |  | 1 |  |  |  | 1,292 |  |  |  | — |
Notional amount |  | $ | — |  |  |  | $ | 12,750 |  |  |  | $ | 91,750 |  |  |  | $ | — |

Presenting offsetting derivatives that are subject to legally enforceable netting arrangements with the same party is permitted. For example, we may have a derivative asset and a derivative liability with the same counterparty to a swap transaction and we are permitted to offset the asset position and the liability position resulting in a net presentation.
The following table indicates the gross amounts of commercial loan swap derivative assets and derivative liabilities, the amounts offset and the carrying values in the Consolidated Balance Sheets as of the dates presented:

| Derivatives (included in Other Assets) |  | Derivatives (included in Other Liabilities)
(dollars in thousands) | March 31, 2020 |  | December 31, 2019 |  | March 31, 2020 |  | December 31, 2019
Derivatives not Designated as Hedging Instruments: |  |  |  |  |  |  |  |  |  |  |
Gross amounts recognized |  | $ | 90,723 |  |  |  | $ | 26,146 |  |  |  | $ | 90,577 |  |  |  | $ | 26,114 |
Gross amounts offset |  | (2,588 | ) |  |  | (499 | ) |  |  | (2,588 | ) |  |  | (499 | )
Net Amounts Presented in the Consolidated Balance Sheets |  | 88,135 |  |  |  | 25,647 |  |  |  | 87,989 |  |  |  | 25,615 |
Gross amounts not offset(1) |  | — |  |  |  | — |  |  |  | (86,720 | ) |  |  | (26,127 | )
Net Amount |  | $ | 88,135 |  |  |  | $ | 25,647 |  |  |  | $ | 1,269 |  |  |  | $ | (512 | )

(1) Amounts represent collateral posted for the periods presented.
The following table indicates the gain or loss recognized in income on derivatives for the periods presented:

| Three Months Ended March 31,
(dollars in thousands) | 2020 |  | 2019
Derivatives not Designated as Hedging Instruments |  |  |  |  |
Interest rate swap contracts—commercial loans |  | $ | 114 |  |  |  | $ | (122 | )
Interest rate lock commitments—mortgage loans |  | 2,606 |  |  |  | 88 |
Forward sale contracts—mortgage loans |  | (1,293 | ) |  |  | 33 |
Total Derivatives Gain/(Loss) |  | $ | 1,427 |  |  |  | $ | (1 | )

37

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 9. BORROWINGS
Short-term borrowings are for terms under or equal to one year and are comprised of securities sold under repurchase agreements, or REPOs and FHLB advances. All REPOs are overnight short-term investments and are not insured by the Federal Deposit Insurance Corporation, or FDIC. Securities pledged as collateral under these REPO financing arrangements cannot be sold or repledged by the secured party and, therefore, the REPOs are accounted for as secured borrowings. Mortgage-backed securities with amortized cost of $66.4 million and carrying value of $70.0 million at March 31, 2020 and amortized cost of $22.7 million and carrying value of $23.0 million at December 31, 2019, were pledged as collateral for these secured transactions. The pledged securities are held in safekeeping at the Federal Reserve. Due to the overnight short-term nature of REPOs, potential risk due to a decline in the value of the pledged collateral is low. Collateral pledging requirements with REPOs are monitored daily. FHLB advances are for various terms and are secured by a blanket lien on residential mortgages and other real estate secured loans.
Long-term borrowings are for original terms greater than one year and are comprised of FHLB advances, finance leases and junior subordinated debt securities. Long-term FHLB advances are secured by the same loans as short-term FHLB advances. We had total long-term borrowings outstanding of $45.6 million at a fixed rate and $67.1 million at a variable rate at March 31, 2020, excluding our finance leases.
Information pertaining to borrowings is summarized in the table below as of the dates presented:

| March 31, 2020 |  | December 31, 2019
(dollars in thousands) | Balance | Weighted Average Rate |  | Balance | Weighted Average Rate
Short-term Borrowings |  |  |  |  |  |  |  |  |
Securities sold under repurchase agreements |  | $ | 69,644 |  |  | 0.25 | % |  |  | $ | 19,888 |  |  | 0.74 | %
Short-term borrowings |  | 410,240 |  |  | 0.44 | % |  |  | 281,319 |  |  | 1.84 | %
Total Short-term Borrowings |  | 479,884 |  |  | 0.41 | % |  |  | 301,207 |  |  | 1.76 | %
Long-term Borrowings |  |  |  |  |  |  |  |  |
Long-term borrowings |  | 50,180 |  |  | 2.59 | % |  |  | 50,868 |  |  | 2.60 | %
Junior subordinated debt securities |  | 64,038 |  |  | 3.63 | % |  |  | 64,277 |  |  | 3.59 | %
Total Long-term Borrowings |  | 114,218 |  |  | 3.17 | % |  |  | 115,145 |  |  | 3.15 | %
Total Borrowings |  | $ | 594,102 |  |  | 0.94 | % |  |  | $ | 416,352 |  |  | 2.14 | %

We had total borrowings at the FHLB of Pittsburgh of $458.9 million at March 31, 2020 and $532.9 million at December 31, 2019. The $458.9 million at March 31, 2020 consisted of $410.2 million in short-term borrowings and $50.2 million in long-term borrowings. Our maximum borrowing capacity with the FHLB of Pittsburgh was $3.1 billion at March 31, 2020. We utilized $698.1 million of our borrowing capacity at March 31, 2020 consisting of $458.9 million for borrowings and $239.2 million for letters of credit to collateralize public funds. Our remaining borrowing availability at March 31, 2020 is $2.4 billion.
We have completed three private placements of trust preferred securities to financial institutions. As a result, we own 100 percent of the common equity of STBA Capital Trust I, DNB Capital Trust I and DNB Capital Trust II, collectively the Trusts. The Trusts were formed to issue mandatorily redeemable capital securities to third-party investors. The proceeds from the sale of the securities and the issuance of the common equity by the Trusts were invested in junior subordinated debt securities issued by us. The Trusts are variable interest entities, and the third-party investors are the primary beneficiaries; therefore, the trusts are not consolidated into our financial statements. The Trusts pays dividends on the securities at the same rate as the interest paid by us on the junior subordinated debt held by the Trusts. DNB Capital Trust I and DNB Capital Trust II were acquired with the DNB merger.
38

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 10. COMMITMENTS AND CONTINGENCIES
Commitments
In the normal course of business, we offer off-balance sheet credit arrangements to enable our customers to meet their financing objectives. These instruments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the financial statements. Our exposure to credit loss, in the event the customer does not satisfy the terms of the agreement, equals the contractual amount of the obligation less the value of any collateral. We apply the same credit policies in making commitments and standby letters of credit that are used for the underwriting of loans to customers. Commitments generally have fixed expiration dates, annual renewals or other termination clauses and may require payment of a fee. Because many of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements.
Estimates of the fair value of these off-balance sheet items were not made because of the short-term nature of these arrangements and the credit standing of the counterparties.
The following table sets forth our commitments and letters of credit as of the dates presented:

(dollars in thousands) | March 31, 2020 |  |  | December 31, 2019 |
Commitments to extend credit |  | $ | 1,967,190 |  |  |  | $ | 1,910,805 |
Standby letters of credit |  | 85,021 |  |  |  | 80,040 |
Total |  | $ | 2,052,211 |  |  |  | $ | 1,990,845 |

Allowance for Credit Losses on Unfunded Loan Commitments
We maintain an allowance for credit losses on unfunded commercial lending commitments and letters of credit to provide for the risk of loss inherent in these arrangements. The allowance is computed using a methodology similar to that used to determine the allowance for credit losses for loans, modified to take into account the probability of a draw-down on the commitment. The provision for credit losses on unfunded loan commitments is included in the provision for credit losses on our Consolidated Statements of Comprehensive Income. The allowance for unfunded commitments is included in other liabilities in the Consolidated Balance Sheets.
The activity in the allowance for credit losses on unfunded loan commitments for the three months ended March 31, 2020 was as follows:

(dollars in thousands) |  | Total
Three months ended March 31, 2020 |  |
Allowance for credit losses on unfunded loan commitments: |  |
Balance at beginning of period |  | $ | 3,112 |
Impact of adopting ASU 2016-13 |  | 1,349 |
January 1, 2020 |  | 4,461 |
Provision for credit losses |  | 1,616 |
March 31, 2020 |  | $ | 6,077 |

Litigation
In the normal course of business, we are subject to various legal and administrative proceedings and claims. While any type of litigation contains a level of uncertainty, we believe that the outcome of such proceedings or claims pending will not have a material adverse effect on our consolidated financial position or results of operations.
39

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 11. REVENUE FROM CONTRACTS WITH CUSTOMERS
We earn revenue from contracts with our customers when we have completed our performance obligations and recognize that revenue when services are provided to our customers. Our contracts with customers are primarily in the form of account agreements. Generally, our services are transferred at a point in time in response to transactions initiated and controlled by our customers under service agreements with an expected duration of one year or less. Our customers have the right to terminate their service agreements at any time.
We do not defer incremental direct costs to obtain contracts with customers that would be amortized in one year or less. These costs are primarily salaries and employee benefits recognized as expense in the period incurred.
Service charges on deposit accounts - We recognize monthly service charges for both commercial and personal banking customers based on account fee schedules. Our performance obligation is generally satisfied and the related revenue recognized at a point in time or over time when the services are provided. Other fees are earned based on specific transactions or customer activity within the customers' deposit accounts. These are earned at the time the transaction or customer activity occurs.
Debit and credit card services - Interchange fees are earned whenever debit and credit cards are processed through third-party card payment networks. ATM fees are based on transactions by our customers' and other customers' use of our ATMs or other ATMs. Debit and credit card revenue is recognized at a point in time when the transaction is settled. Our performance obligation to our customers is generally satisfied and the related revenue is recognized at a point in time when the service is provided. Third-party service contracts include annual volume and marketing incentives which are recognized over a period of twelve months when we meet thresholds as stated in the service contract.
Wealth management services - Wealth management services are primarily comprised of fees earned from the management and administration of trusts, assets under administration and other financial advisory services. Generally, wealth management fees are earned over a period of time between monthly and annually, per the related fee schedules. Our performance obligations with our customers are generally satisfied when we provide the services as stated in the customers' agreements. The fees are based on a fixed amount or a scale based on the level of services provided or amount of assets under management.
Other fee revenue - Other fee revenue includes a variety of other traditional banking services such as, electronic banking fees, letters of credit origination fees, wire transfer fees, money orders, treasury checks, checksale fees and transfer fees. Our performance obligations are generally satisfied at a point in time, while fee revenue is recognized when the services are provided or the transaction is settled.
The information presented in the following table presents the point of revenue recognition for revenue from contracts with customers. Other revenue streams such as: interest income, net securities gains and losses, insurance, mortgage banking and other revenues that are accounted for under other generally accepted accounting principles are excluded.

(dollars in thousands) |  | Three Months Ended March 31,
Revenue Streams | Point of Revenue Recognition | 2020 |  |  | 2019 |
Service charges on deposit accounts | Over a period of time | $ | 484 |  |  | $ | 457 |
| At a point in time | 3,074 |  |  | 2,696 |
|  | $ | 3,558 |  |  | $ | 3,153 |
Debit and credit card | Over a period of time | $ | 194 |  |  | $ | 185 |
| At a point in time | 3,287 |  |  | 2,789 |
|  | $ | 3,482 |  |  | $ | 2,974 |
Wealth management | Over a period of time | $ | 345 |  |  | $ | 413 |
| At a point in time | 2,018 |  |  | 1,635 |
|  | $ | 2,362 |  |  | $ | 2,048 |
Other fee revenue | At a point in time | $ | 919 |  |  | $ | 919 |

40

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 12. OTHER COMPREHENSIVE INCOME/(LOSS)
The following table presents the change in components of other comprehensive income/(loss) for the periods presented, net of tax effects.

| Three Months Ended March 31, 2020 |  | Three Months Ended March 31, 2019
(dollars in thousands) | Pre-Tax Amount |  |  | Tax (Expense) Benefit |  |  | Net of Tax Amount |  |  | Pre-Tax Amount |  |  | Tax (Expense) Benefit |  |  | Net of Tax Amount |
Change in net unrealized gains/(losses) on available-for-sale debt securities (1) |  | $ | 21,568 |  |  |  | $ | (4,592 | ) |  |  | $ | 16,976 |  |  |  | $ | 7,398 |  |  |  | $ | (1,578 | ) |  |  | $ | 5,820 |
Adjustment to funded status of employee benefit plans |  | 465 |  |  |  | (99 | ) |  |  | 366 |  |  |  | 453 |  |  |  | (97 | ) |  |  | 356 |
Other Comprehensive Income/(Loss) |  | $ | 22,033 |  |  |  | $ | (4,691 | ) |  |  | $ | 17,342 |  |  |  | $ | 7,851 |  |  |  | $ | (1,675 | ) |  |  | $ | 6,176 |
(1) Reclassification adjustments are comprised of realized security gains or losses. The realized gains or losses have been reclassified out of accumulated other comprehensive income/(loss) and have affected certain lines in the Consolidated Statements of Comprehensive Income as follows: the pre-tax amount is included in net gain on sale of securities, the tax expense amount is included in the provision for income taxes and the net of tax amount is included in net income. There were no reclassification adjustments for the three months ended March 31, 2020 or 2019.

NOTE 13. EMPLOYEE BENEFITS
Our qualified and nonqualified defined benefit plans were amended to freeze benefit accruals for all persons entitled to benefits under the plans in 2016. We will continue recording pension expense related to these plans, primarily representing interest costs on the accumulated benefit obligation and amortization of actuarial losses accumulated in the plans, as well as income from expected investment returns on pension assets. Since the plans have been frozen, no service costs are included in net periodic pension expense.
The defined benefit plan of DNB was merged into S&T's defined benefit plan at November 30, 2019 and the components of net periodic pension cost at March 31, 2020 include the impact of the addition of the DNB defined benefit plan.
The investment policy for S&T's defined benefit plan is 85 percent to 95 percent fixed income and 5 percent to 15 percent equity and cash. The expected long-term rate of return on plan assets is 3.50 percent compared to 4.80 percent in prior periods.
The following table summarizes the components of net periodic pension cost for the periods presented:

| Three Months Ended March 31,
(dollars in thousands) | 2020 |  | 2019
Components of Net Periodic Pension Cost |  |  |  |  |
Interest cost on projected benefit obligation |  | $ | 891 |  |  |  | $ | 989 |
Expected return on plan assets |  | (972 | ) |  |  | (1,180 | )
Net amortization |  | 384 |  |  |  | 394 |
Net Periodic Pension Expense |  | $ | 303 |  |  |  | $ | 203 |

The components of net periodic pension expense are included in salaries and employee benefits on the Consolidated Statements of Comprehensive Income.
41

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 14. QUALIFIED AFFORDABLE HOUSING
As part of our responsibilities under the Community Reinvestment Act and due to their favorable federal income tax benefits, we invest in Low Income Housing projects. As a limited partner in these operating partnerships, we receive tax credits and tax deductions for losses incurred by the underlying properties. We use the cost method to account for these partnerships.
Our total investment in qualified affordable housing projects was $6.4 million at March 31, 2020 and $4.8 million at December 31, 2019. Amortization expense, included in other noninterest expense in the Consolidated Statements of Comprehensive Income, was $0.6 million for the three months ended March 31, 2020 and $0.7 million for the three months ended March 31, 2019. The amortization expense was offset by tax credits of $0.6 million for the three months ended March 31, 2020 and $0.7 million for the three months ended March 31, 2019 as a reduction to our federal tax provision.
On September 11, 2019, we entered into a new qualified affordable housing project and committed to an investment of $10.2 million. As of March 31, 2020, we have invested $3.6 million in this new project. No amortization expense or tax credits will be recognized for this new project until complete, which we expect to be later in 2020.
NOTE 15. SHARE REPURCHASE PLAN
On September 16, 2019, our Board of Directors authorized a $50 million share repurchase plan. This repurchase authorization, which is effective through March 31, 2021, permits S&T to repurchase from time to time up to $50 million in aggregate value of shares of S&T's common stock through a combination of open market and privately negotiated repurchases. The specific timing, price and quantity of repurchases will be at the discretion of S&T and will depend on a variety of factors, including general market conditions, the trading price of common stock, legal and contractual requirements, applicable securities laws and S&T's financial performance. The repurchase plan does not obligate us to repurchase any particular number of shares. We expect to fund any repurchases from cash on hand and internally generated funds. During the three months ended March 31, 2020, we repurchased 411,430 common shares at a total cost of $12.6 million, or an average of $30.52 per share. Repurchase activity was suspended in March as the impact of the COVID-19 pandemic spread.
42

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
NOTES TO CONSOLIDATED FINANCIAL STATEMENTS – continued
NOTE 16. SUBSEQUENT EVENTS
Paycheck Protection Program
On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security, or CARES Act was signed into law. It contains substantial tax and spending provisions intended to address the impact of the COVID-19 pandemic. The CARES Act includes the Paycheck Protection Program, or PPP, a $349 billion program designed to aid small and medium sized businesses through federally guaranteed loans distributed through banks. The Paycheck Protection Program and Health Care Enhancement Act, or PPP/HCEA Act, was signed into law on April 24, 2020. Among other provisions, the PPP/HCEA Act authorized an additional $310 billion of funding under the CARES Act for PPP loans. These loans are intended to cover eight weeks of payroll and other costs to help those businesses remain viable. As of May 5, 2020, we had obtained approvals for 2,959 loans totaling $548.0 million.
PPP loans are forgivable, in whole or in part, if the proceeds are used for payroll and other permitted expenses in accordance with the requirements of the PPP. These loans carry a fixed rate of 1.00 percent and a term of two years, if not forgiven, in whole or in part. Payments are deferred for the first six months of the loan. The loans are 100 percent guaranteed by the SBA. The SBA pays the originating bank a processing fee ranging from 1 percent to 5 percent based on the size of the loan.
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
Management’s Discussion and Analysis of Financial Condition and Results of Operations, or MD&A, represents an overview of our consolidated results of operations and financial condition and highlights material changes in our financial condition and results of operations at and for the three month periods ended March 31, 2020 and 2019. Our MD&A should be read in conjunction with our Consolidated Financial Statements and Notes. The results of operations reported in the accompanying Consolidated Financial Statements are not necessarily indicative of results to be expected in future periods.
Important Note Regarding Forward-Looking Statements
This quarterly report on Form 10-Q contains or incorporates statements that we believe are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements generally relate to our financial condition, results of operations, plans, objectives, outlook for earnings, revenues, expenses, capital and liquidity levels and ratios, asset levels, asset quality, financial position, and other matters regarding or affecting S&T and its future business and operations. Forward-looking statements are typically identified by words or phrases such as “will likely result”, “expect”, “anticipate”, “estimate”, “forecast”, “project”, “intend”, “ believe”, “assume”, “strategy”, “trend”, “plan”, “outlook”, “outcome”, “continue”, “remain”, “potential”, “opportunity”, “believe”, “comfortable”, “current”, “position”, “maintain”, “sustain”, “seek”, “achieve” and variations of such words and similar expressions, or future or conditional verbs such as will, would, should, could or may. Although we believe the assumptions upon which these forward-looking statements are based are reasonable, any of these assumptions could prove to be inaccurate and the forward-looking statements based on these assumptions could be incorrect. The matters discussed in these forward-looking statements are subject to various risks, uncertainties and other factors that could cause actual results and trends to differ materially from those made, projected, or implied in or by the forward-looking statements depending on a variety of uncertainties or other factors including, but not limited to: credit losses and the credit risk of our commercial and consumer loan products; changes in the level of charge-offs and changes in estimates of the adequacy of the allowance for credit losses; cyber-security concerns; rapid technological developments and changes; sensitivity to the interest rate environment including a prolonged period of low interest rates, a rapid increase in interest rates or a change in the shape of the yield curve; a change in spreads on interest-earning assets and interest-bearing liabilities; regulatory supervision and oversight, including changes in regulatory capital requirements and our ability to address those requirements; changes in accounting policies, practices, or guidance, for example, our adoption of CECL; legislation affecting the financial services industry as a whole, and S&T, in particular; the outcome of pending and future litigation and governmental proceedings; increasing price and product/service competition; the ability to continue to introduce competitive new products and services on a timely, cost-effective basis; managing our internal growth and acquisitions; the possibility that the anticipated benefits from acquisitions, including DNB, cannot be fully realized in a timely manner or at all, or that integrating the acquired operations will be more difficult, disruptive or costly than anticipated;
43

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
containing costs and expenses; reliance on significant customer relationships; an interruption or cessation of an important service by a third-party provider; general economic or business conditions, including the strength of regional economic conditions in our market area; the duration and severity of the coronavirus (“COVID-19”) pandemic, both in our principal area of operations and nationally, including the ultimate impact of the pandemic on the economy generally and on our operations; deterioration of the housing market and reduced demand for mortgages; deterioration in the overall macroeconomic conditions or the state of the banking industry that could warrant further analysis of the carrying value of goodwill and could result in an adjustment to its carrying value resulting in a non-cash charge to net income; the stability of our core deposit base and access to contingency funding; re-emergence of turbulence in significant portions of the global financial and real estate markets that could impact our performance, both directly, by affecting our revenues and the value of our assets and liabilities, and indirectly, by affecting the economy generally and access to capital in the amounts, at the times and on the terms required to support our future businesses.
Many of these factors, as well as other factors, are described in our Annual Report on Form 10-K for the year ended December 31, 2019, including Part I, Item 1A-"Risk Factors" and any of our subsequent filings with the SEC. Forward-looking statements are based on beliefs and assumptions using information available at the time the statements are made. We caution you not to unduly rely on forward-looking statements because the assumptions, beliefs, expectations and projections about future events may, and often do, differ materially from actual results. Any forward-looking statement speaks only as to the date on which it is made, and we undertake no obligation to update any forward-looking statement to reflect developments occurring after the statement is made.
Critical Accounting Policies and Estimates
Our critical accounting policies involving significant judgments and assumptions used in the preparation of the Consolidated Financial Statements as of March 31, 2020 have remained unchanged from the disclosures presented in our Annual Report on Form 10-K for the year ended December 31, 2019 under Part II, Item 7 - “Management’s Discussion and Analysis of Financial Condition and Results of Operations” except for we have updated our allowance for credit losses policy in response to the adoption of ASU 2016-13 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.
Allowance for Credit Losses
The ACL is a valuation reserve established and maintained by charges against operating income and is deducted from the amortized cost basis of loans to present the net amount expected to be collected on the loans. Loans, or portions thereof, are charged off against the ACL when they are deemed uncollectible. Expected recoveries do not exceed the aggregate of amounts previously charged-off and expected to be charged-off. The ACL is an estimate of expected credit losses, measured over the contractual life of a loan, that considers our historical loss experience, current conditions and forecasts of future economic conditions. Determination of an appropriate ACL is inherently subjective and may have significant changes from period to period.
The methodology for determining the ACL has two main components: evaluation of expected credit losses for certain groups of homogeneous loans that share similar risk characteristics and evaluation of loans that do not share risk characteristics with other loans.
The ACL for homogeneous loans is calculated using a life-time loss rate methodology with both a quantitative and a qualitative analysis that is applied on a quarterly basis. The ACL model is comprised of six distinct portfolio segments: 1) Construction, 2) Commercial Real Estate, or CRE, 3) Commercial and Industrial, or C&I, 4) Business Banking, 5) Consumer Real Estate and 6) Other Consumer. Each segment has a distinct set of risk characteristics monitored by management. We further evaluate the ACL at a disaggregated level which includes type of collateral and our internal risk rating system for the commercial segments and type of collateral, lien position, and FICO score, for the consumer segments. Historical credit loss experience is the basis for the estimation of expected credit losses. We apply historical loss rates to pools of loans with similar risk characteristics. After consideration of the historic loss calculation, management applies qualitative adjustments to reflect the current conditions and reasonable and supportable forecasts not already reflected in the historical loss information at the balance sheet date. Our reasonable and supportable forecast adjustment is based on the unemployment forecast and management judgment. For periods beyond which we are able to develop reasonable and supportable forecasts, we revert to the historical loss rate. The qualitative adjustments for current conditions are based upon changes in lending policies and practices, experience and ability of lending staff, quality of the bank’s loan review system, value of underlying collateral for collateral dependent loans, the existence of and changes in concentrations and other external factors. These modified historical loss rates are multiplied by the outstanding principal balance of each loan to calculate a required reserve. A similar process is employed to calculate a reserve assigned to off-balance sheet commitments, specifically unfunded loan commitments and letters of credit, and any needed reserve is recorded in other liabilities.
44

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
The ACL for individual loans begins with the use of normal credit review procedures to identify whether a loan no longer shares similar risk characteristics with other pooled loans and therefore, should be individually assessed. We evaluate all commercial loans greater than $0.5 million that meet the following criteria: 1) when it is determined that foreclosure is probable, 2) substandard, doubtful and nonperforming loans when repayment is expected to be provided substantially through the operation or sale of the collateral, 3) any commercial troubled debt restructuring (TDR), or any loan reasonably expected to become a TDR whether on accrual or nonaccrual status and 4) when it is determined by management that a loan does not share similar risk characteristics with other loans. Specific reserves are established based on the following three acceptable methods for measuring the ACL: 1) the present value of expected future cash flows discounted at the loan’s original effective interest rate; 2) the loan’s observable market price; or 3) the fair value of the collateral when the loan is collateral dependent. Our individual loan evaluations consist primarily of the fair value of collateral method because most of our loans are collateral dependent. Collateral values are discounted to consider disposition costs when appropriate. A specific reserve is established or a charge-off is taken if the fair value of the loan is less than the recorded investment in the loan balance.
Although we believe our process for determining the ACL appropriately considers all the factors that would likely result in credit losses, the process includes subjective elements and may be susceptible to significant change. To the extent actual losses are higher than management estimates, additional provision for credit losses could be required and could adversely affect our earnings or financial position in future periods.
Overview
We are a bank holding company that is headquartered in Indiana, Pennsylvania with assets of $9.0 billion at March 31, 2020. We operate in five markets including Western Pennsylvania, Eastern Pennsylvania, Northeast Ohio, Central Ohio, and Upstate New York.
We provide a full range of financial services with retail and commercial banking products, cash management services, trust and brokerage services. Our common stock trades on the NASDAQ Global Select Market under the symbol “STBA”.
We earn revenue primarily from interest on loans and securities and fees charged for financial services provided to our customers. We incur expenses for the cost of deposits and other funding sources, provision for credit losses and other operating costs such as salaries and employee benefits, data processing, occupancy and tax expense.
Our mission is to become the financial services provider of choice within the markets that we serve which will enable us to continue to be a high performing regional community bank. We strive to do this by delivering exceptional service and value, one customer at a time. Our strategic plan follows a disciplined approach focused on organic growth, which includes both growth within our current footprint and through market expansion. We employ a geographic market-based growth platform in order to drive organic growth. Each of our five markets is led by a Market President who is responsible for developing strategic initiatives specific to each market. We acknowledge that each of our five markets are in different stages of development and that our market based strategy will allow us to customize our approach to each market given its developmental stage and unique characteristics. We also actively evaluate acquisition opportunities that align with our strategic objectives as another source of growth. Our strategic plan includes a collaborative model that combines expertise from all areas of our business and focuses on satisfying each customer’s individual financial objectives. We continuously work to maintain and improve the efficiency of our different lines of business.
We merged with DNB Financial Corporation (DNB) on November 30, 2019. The merger expanded S&T’s footprint in Eastern Pennsylvania gaining a new presence in the counties of Chester, Delaware and Philadelphia. The merger was valued at $201.0 million, or $37.72 per share, and added approximately $899.3 million of portfolio loans and $990.6 million of deposits at December 31, 2019.
Our focus continues to be on organic loan and deposit growth and implementing opportunities to increase fee income while closely monitoring our operating expenses and asset quality. We are focused on executing our strategy to successfully build our brand and grow our business in all of our markets.
COVID-19 Update
S&T is monitoring and will continue to monitor the impact of the novel coronavirus (“COVID-19”) pandemic and has
taken and will continue to take steps to mitigate the potential risks and impact on S&T and to promote the health and safety of
our employees, and the customers and communities we serve. In response to the COVID-19 pandemic, preventive health
measures including social distancing, wearing masks, remote work where feasible, extra cleaning and branch access restrictions
have been implemented. Our Business Continuity teams were activated and have guided our efforts to respond to the
rapidly developing situation. Furthermore, as described in Note 16 of Notes to Consolidated Financial Statements, we are participating in the PPP, designed to aid small and medium sized businesses to address the impact of the COVID-19 pandemic.
The extent to which COVID-19 may adversely impact our business depends on future developments, which are highly
45

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
uncertain and unpredictable. The COVID-19 pandemic has had, and we expect that it will continue to have, negative impacts
on S&T’s commercial and consumer loan customers and the economy as a whole. The severity and length of the
COVID-19 pandemic’s impact on S&T and the U.S. and global economies are unknown. In order to assist our customers through this difficult period we have provided the following assistance, which may have an adverse impact on our results in the short term, but which we believe will provide better outcomes in the long term for our customers and for S&T:

• | We have provided needs-based payment deferrals and modifications to interest only periods to commercial loan

customers.

• | We have provided mortgage and consumer loan payment deferrals with no negative credit bureau reporting to

consumer customers.

• | We have paused foreclosures/repossessions for mortgages and consumer loans.

Earnings Summary
Net income decreased $9.7 million, or 42.3 percent, to $13.2 million, or $0.34 per diluted share, for the three months ended March 31, 2020 compared to $22.9 million, or $0.66 per diluted share, in 2019. The decrease in net income was primarily due to the potential impact of COVID-19 on our expected credit losses which contributed to an increased provision for credit losses of $14.4 million, an increase in other noninterest expenses of $7.5 million, which included $2.3 million, or $0.05 per diluted share, of merger related expenses. These increases were offset by an increase of $9.7 million in net interest income which was primarily a result of the merger.
Net interest income increased $9.7 million, or 16.0 percent, to $70.0 million compared to $60.3 million for the three months ended March 31, 2019. The increase was primarily due to higher average interest-earning assets of $1.4 billion. The majority of the increase came from higher average loans of $1.2 billion from organic loan growth combined with $900 million of loans from the DNB Merger. Average interest-bearing liabilities increased $1.0 billion, primarily from increases in average interest-bearing deposits from the DNB merger. Net interest margin, on a fully taxable-equivalent, or FTE, basis (non-GAAP), declined 18 basis points to 3.53 percent compared to 3.71 percent from the year ago period due to the declining interest rate environment. Net interest margin is reconciled to net interest income adjusted to an FTE basis below in the "Net Interest Income" section of this MD&A.
The provision for credit losses, which includes a provision for losses on unfunded commitments, increased $14.4 million to $20.1 million for the three months ended March 31, 2020 compared to $5.7 million in the same period of 2019. The significant increase in the provision for credit losses was mainly due to a $16.3 million increase in our ACL in response to the COVID-19 pandemic. Net loan charge-offs increased $6.0 million to $11.2 million, or 0.63 percent of average loans, for the three months ended March 31, 2020 compared to $5.2 million, or 0.36 percent of average loans, in the same period in 2019.
Total noninterest income increased $1.0 million to $12.4 million for the three months ended March 31, 2020 compared to $11.4 million in the same period of 2019. Total noninterest income includes the impact of the DNB merger in the three months ended March 31, 2020 since the merger closed on November 30, 2019. The increase in noninterest income primarily related to higher commercial loan swap income of $1.9 million as we continue to see a high demand for this product in the current rate environment. Also impacting the increase was $0.7 million in mortgage banking fees, $0.5 million in debit and credit card fees and $0.4 million in service charges on deposit accounts. Offsetting these increases was a $2.8 million decrease in other income primarily attributable to the decline in stock market performance during the first quarter of 2020 resulting in a change in the valuation related to a deferred compensation plan of $1.8 million, which has a corresponding offset in salaries and benefit expense resulting in no impact to net income and a decrease in the equity securities portfolio of $1.3 million compared to the prior period.
Noninterest expense increased $7.5 million to $46.4 million in three months ended March 31, 2020 compared to $38.9 million in the same period in 2019. Total noninterest expense includes the impact of the DNB merger in the three months ended March 31, 2020 since the merger closed on November 30, 2019. We incurred $2.3 million of merger related expenses in the three months ended March 31, 2020 and higher operating expenses after the merger with DNB. Other noninterest expense increased $2.6 million mainly due to $1.1 million increase related to historic tax credits and $0.5 million of additional amortization related to the DNB merger.
The provision for income taxes decreased $1.5 million to $2.7 million for the three months ended March 31, 2020 compared to $4.2 million in the same period in 2019 as a result of the decrease in pretax income of $11.2 million. Our effective tax rate increased to 17.3 percent for the three months ended March 31, 2020 compared to 15.6 percent for the same period in 2019. The increase in the effective tax rate is primarily due to a $1.7 million decrease in benefits from tax credits in the first quarter of 2020 compared to the same period of 2019.
46

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
Explanation of Use of Non-GAAP Financial Measures
In addition to the results of operations presented in accordance with generally accepted accounting principles, or GAAP, in the United States, management uses, and this quarterly report references, net interest income and net interest margin on a fully taxable equivalent, or FTE, basis, which are non-GAAP financial measures. Management believes net interest income and net interest margin on an FTE basis provide information useful to investors in understanding our underlying business, operational performance and performance trends as they facilitate comparisons with the performance of other companies in the financial services industry. Although management believes that these non-GAAP financial measures enhance investors’ understanding of our business and performance, these non-GAAP financial measures should not be considered alternatives to GAAP or considered to be more important than financial results determined in accordance with GAAP, nor are they necessarily comparable with non-GAAP measures which may be presented by other companies.
We believe the presentation of net interest income and net interest margin on an FTE basis ensures the comparability of net interest income arising from both taxable and tax-exempt sources and is consistent with industry practice. Interest income (GAAP) per the Consolidated Statements of Comprehensive Income is reconciled to net interest income adjusted on an FTE basis and net interest margin adjusted on an FTE basis in the "Results of Operations - Three Months Ended March 31, 2020 Compared to Three Months Ended March 31, 2019 - Net Interest Income" section of this MD&A.
RESULTS OF OPERATIONS
Three Months Ended March 31, 2020 Compared to
Three Months Ended March 31, 2019
Net Interest Income
Our principal source of revenue is net interest income. Net interest income represents the difference between the interest and fees earned on interest-earning assets and the interest paid on interest-bearing liabilities. Net interest income is affected by changes in the average balance of interest-earning assets and interest-bearing liabilities and changes in interest rates and spreads. The level and mix of interest-earning assets and interest-bearing liabilities is managed by our ALCO, in order to mitigate interest rate and liquidity risks of the balance sheet. A variety of ALCO strategies were implemented, within prescribed ALCO risk parameters, to produce what we believe is an acceptable level of net interest income.
The interest income on interest-earning assets and the net interest margin are presented on an FTE basis. The FTE basis adjusts for the tax benefit of income on certain tax-exempt loans and securities using the federal statutory tax rate of 21 percent for each period and the dividend-received deduction for equity securities. We believe this to be the preferred industry measurement of net interest income that provides a relevant comparison between taxable and non-taxable sources of interest income.
The following table reconciles interest income per the Consolidated Statements of Comprehensive Income to net interest income and rates on an FTE basis for the periods presented:

| Three Months Ended March 31,
(dollars in thousands) | 2020 |  | 2019
Total interest income |  | $ | 87,589 |  |  |  | $ | 78,590 |
Total interest expense |  | 17,553 |  |  |  | 18,234 |
Net Interest Income per Consolidated Statements of Comprehensive Income |  | 70,036 |  |  |  | 60,356 |
Adjustment to FTE basis |  | 849 |  |  |  | 961 |
Net Interest Income on an FTE Basis (Non-GAAP) |  | $ | 70,885 |  |  |  | $ | 61,317 |
Net interest margin |  | 3.48 | % |  |  | 3.65 | %
Adjustment to FTE basis |  | 0.05 | % |  |  | 0.06 | %
Net Interest Margin on an FTE Basis (Non-GAAP) |  | 3.53 | % |  |  | 3.71 | %

Income amounts are annualized for rate calculations.
47

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
Average Balance Sheet and Net Interest Income Analysis (FTE)
The following tables provide information regarding the average balances, interest and rates earned on interest-earning assets and the average balances, interest and rates paid on interest-bearing liabilities for the periods presented:

| Three Months Ended March 31, 2020 |  | Three Months Ended March 31, 2019
(dollars in thousands) | Average Balance | Interest | Rate |  | Average Balance | Interest | Rate
ASSETS |  |  |  |  |  |  |  |  |
Interest-bearing deposits with banks | $ | 99,646 |  |  | $ | 355 |  | 1.42 | % |  | $ | 53,588 |  |  | $ | 352 |  | 2.63 | %
Securities, at fair value(2)(3) | 786,858 |  |  | 4,995 |  | 2.54 | % |  | 680,517 |  |  | 4,558 |  | 2.68 | %
Loans held for sale | 1,867 |  |  | 18 |  | 3.76 | % |  | 894 |  |  | 9 |  | 4.07 | %
Commercial real estate | 3,408,684 |  |  | 40,093 |  | 4.73 | % |  | 2,905,272 |  |  | 35,964 |  | 5.02 | %
Commercial and industrial | 1,751,678 |  |  | 19,738 |  | 4.53 | % |  | 1,508,658 |  |  | 19,333 |  | 5.20 | %
Commercial construction | 386,363 |  |  | 4,495 |  | 4.68 | % |  | 249,997 |  |  | 3,312 |  | 5.37 | %
Total Commercial Loans | 5,546,725 |  |  | 64,326 |  | 4.66 | % |  | 4,663,927 |  |  | 58,609 |  | 5.10 | %
Residential mortgage | 990,866 |  |  | 10,328 |  | 4.18 | % |  | 722,554 |  |  | 7,869 |  | 4.38 | %
Home equity | 540,193 |  |  | 6,501 |  | 4.84 | % |  | 467,739 |  |  | 6,269 |  | 5.44 | %
Installment and other consumer | 79,680 |  |  | 1,388 |  | 7.01 | % |  | 69,099 |  |  | 1,222 |  | 7.17 | %
Consumer construction | 10,508 |  |  | 120 |  | 4.61 | % |  | 9,466 |  |  | 144 |  | 6.19 | %
Total Consumer Loans | 1,621,247 |  |  | 18,337 |  | 4.54 | % |  | 1,268,858 |  |  | 15,504 |  | 4.93 | %
Total Portfolio Loans | 7,167,972 |  |  | 82,663 |  | 4.64 | % |  | 5,932,785 |  |  | 74,113 |  | 5.06 | %
Total Loans(1)(2) | 7,169,839 |  |  | 82,681 |  | 4.64 | % |  | 5,933,679 |  |  | 74,122 |  | 5.06 | %
Federal Home Loan Bank and other restricted stock | 23,601 |  |  | 407 |  | 6.90 | % |  | 24,471 |  |  | 519 |  | 8.90 | %
Total Interest-earning Assets | 8,079,944 |  |  | 88,438 |  | 4.40 | % |  | 6,692,255 |  |  | 79,551 |  | 4.81 | %
Noninterest-earning assets | 687,382 |  |  |  |  |  | 518,500 |  |  |  |
Total Assets | $ | 8,767,326 |  |  |  |  |  | $ | 7,210,755 |  |  |  |
LIABILITIES AND SHAREHOLDERS’ EQUITY |  |  |  |  |  |  |  |  |
Interest-bearing demand | $ | 942,030 |  |  | $ | 1,382 |  | 0.59 | % |  | $ | 54,695 |  |  | $ | 553 |  | 0.41 | %
Money market | 1,993,764 |  |  | 6,318 |  | 1.27 | % |  | 1,568,417 |  |  | 7,292 |  | 1.89 | %
Savings | 830,985 |  |  | 477 |  | 0.23 | % |  | 770,587 |  |  | 472 |  | 0.25 | %
Certificates of deposit | 1,601,324 |  |  | 7,161 |  | 1.80 | % |  | 1,434,511 |  |  | 6,664 |  | 1.88 | %
Total Interest-bearing Deposits | 5,368,103 |  |  | 15,338 |  | 1.15 | % |  | 4,319,210 |  |  | 14,981 |  | 1.41 | %
Securities sold under repurchase agreements | 30,790 |  |  | 42 |  | 0.56 | % |  | 23,170 |  |  | 29 |  | 0.52 | %
Short-term borrowings | 286,365 |  |  | 1,145 |  | 1.61 | % |  | 319,389 |  |  | 2,145 |  | 2.72 | %
Long-term borrowings | 51,845 |  |  | 325 |  | 2.52 | % |  | 70,196 |  |  | 493 |  | 2.84 | %
Junior subordinated debt securities | 64,195 |  |  | 703 |  | 4.40 | % |  | 45,619 |  |  | 586 |  | 5.21 | %
Total Borrowings | 433,195 |  |  | 2,215 |  | 2.06 | % |  | 458,374 |  |  | 3,253 |  | 2.88 | %
Total Interest-bearing Liabilities | 5,801,298 |  |  | 17,553 |  | 1.22 | % |  | 4,777,584 |  |  | 18,234 |  | 1.55 | %
Noninterest-bearing liabilities | 1,776,453 |  |  |  |  |  | 1,448,057 |  |  |  |
Shareholders’ equity | 1,189,575 |  |  |  |  |  | 945,114 |  |  |  |
Total Liabilities and Shareholders’ Equity | $ | 8,767,326 |  |  |  |  |  | $ | 7,210,755 |  |  |  |
Net Interest Income (2)(3) |  |  | $ | 70,885 |  |  |  |  |  | $ | 61,317 |  |
Net Interest Margin (2)(3) |  |  |  | 3.53 | % |  |  |  |  | 3.71 | %

(1) Nonaccruing loans are included in the daily average loan amounts outstanding.
(2) Tax-exempt income is on an FTE basis (non-GAAP) using the statutory federal corporate income tax rate of 21 percent for 2020 and 2019.
(3) Taxable investment income is adjusted for the dividend-received deduction for equity securities.
48

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
Net interest income on an FTE basis (non-GAAP) increased $9.6 million, or 15.6 percent, for the three months ended March 31, 2020 compared to the same period in 2019. The net interest margin on an FTE basis (non-GAAP) decreased 18 basis points for the three months ended March 31, 2020 compared to the same period in 2019.
Interest income on an FTE basis (non-GAAP) increased $8.9 million, or 11.2 percent, for the three months ended March 31, 2020 compared to the same period in 2019. The increase was primarily due to increases in average interest-earning assets of $1.4 billion for the three months ended March 31, 2020 offset by lower short-term interest rates compared to the same period in 2019. Average loan balances increased $1.2 billion compared to the same period in 2019 due to the DNB merger and organic loan growth. The average rate earned on loans decreased 42 basis points compared to the same period in 2019 primarily due to lower short-term interest rates. Average investment securities increased $106.3 million and the average rate earned decreased 14 basis points compared to the same period in 2019. Overall, the FTE rate on interest-earning assets (non-GAAP) decreased 41 basis points for the three months ended March 31, 2020 compared to the same period in 2019.
Interest expense decreased $0.7 million for the three months ended March 31, 2020 compared to the same period in 2019. The decrease was primarily due to lower short-term interest rates compared to the same period in 2019. Average interest-bearing deposits increased $1.0 billion compared to the same period in 2019 due to the DNB merger and organic deposit growth. The average rate paid decreased 26 basis points compared to the same period in 2019 primarily due to lower short-term interest rates. Average total borrowings decreased $25.2 million and the average rate paid decreased 82 basis points compared to the same period in 2019. Overall, the cost of interest-bearing liabilities decreased 33 basis points for the three months ended March 31, 2020, compared to the same period in 2019.
49

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
The following table sets forth for the periods presented a summary of the changes in interest earned and interest paid resulting from changes in volume and changes in rates:

| Three Months Ended March 31, 2020 Compared to March 31, 2019
(dollars in thousands) | Volume (4) | Rate (4) | Total
Interest earned on: |  |  |
Interest-bearing deposits with banks | $ | 302 |  | $ | (299 | ) | $ | 3 |
Securities, at fair value(2)(3) | 712 |  | (274 | ) | 438 |
Loans held for sale | 10 |  | (1 | ) | 9 |
Commercial real estate | 6,232 |  | (2,103 | ) | 4,129 |
Commercial and industrial | 3,114 |  | (2,709 | ) | 405 |
Commercial construction | 1,807 |  | (623 | ) | 1,184 |
Total Commercial Loans | 11,153 |  | (5,435 | ) | 5,718 |
Residential mortgage | 2,922 |  | (463 | ) | 2,459 |
Home equity | 971 |  | (739 | ) | 232 |
Installment and other consumer | 187 |  | (21 | ) | 166 |
Consumer construction | 16 |  | (40 | ) | (24 | )
Total Consumer Loans | 4,096 |  | (1,263 | ) | 2,833 |
Total Portfolio Loans | 15,249 |  | (6,698 | ) | 8,551 |
Total Loans (1)(2) | 15,259 |  | (6,699 | ) | 8,560 |
Federal Home Loan Bank and other restricted stock | (18 | ) | (94 | ) | (112 | )
Change in Interest Earned on Interest-earning Assets | 16,255 |  | (7,366 | ) | 8,889 |
Interest paid on: |  |  |
Interest-bearing demand |  | $401 |  |  | $428 |  |  | $829 |
Money market | 1,977 |  | (2,951 | ) | (974 | )
Savings | 37 |  | (33 | ) | 4 |
Certificates of deposit | 775 |  | (278 | ) | 497 |
Total Interest-bearing Deposits | 3,190 |  | (2,834 | ) | 356 |
Securities sold under repurchase agreements | 10 |  | 4 |  | 14 |
Short-term borrowings | (222 | ) | (779 | ) | (1,001 | )
Long-term borrowings | (129 | ) | (39 | ) | (168 | )
Junior subordinated debt securities | 239 |  | (121 | ) | 118 |
Total Borrowings | (102 | ) | (935 | ) | (1,037 | )
Change in Interest Paid on Interest-bearing Liabilities | 3,088 |  | (3,769 | ) | (681 | )
Change in Net Interest Income | $ | 13,167 |  | $ | (3,597 | ) | $ | 9,570 |

(1) Nonaccruing loans are included in the daily average loan amounts outstanding.
(2) Tax-exempt income is on an FTE basis (non-GAAP) using the statutory federal corporate income tax rate of 21 percent for 2020 and 2019.
(3) Taxable investment income is adjusted for the dividend-received deduction for equity securities.
(4) Changes to rate/volume are allocated to both rate and volume on a proportionate dollar basis.
Provision for Credit Losses
The provision for credit losses, which includes a provision for losses on unfunded commitments, is a charge to earnings to maintain the ACL at a level consistent with management's assessment of expected losses in the loan portfolio at the balance sheet date. At January 1, 2020, we increased the ACL by $27.3 million for the day one CECL adjustment. The provision for credit losses increased $14.4 million to $20.1 million for the three months ended March 31, 2020 compared to $5.7 million for the same period in 2019. The provision for credit losses includes $1.6 million for the reserve for unfunded commitments for the three months ended March 31, 2020.
The significant increase in the provision for credit losses during the three months ended March 31, 2020 was mainly due to the COVID-19 pandemic. We added approximately $14.9 million to the ACL in the first quarter of 2020 related to qualitative factors. This included $11.2 million for a revised economic forecast and the impact of that forecast on certain loan portfolios due to the COVID-19 pandemic. Changes in current conditions resulted in an additional $3.7 million increase in the ACL.
50

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
Net loan charge-offs increased $6.0 million to $11.2 million, or 0.63 percent of average loans, for the first quarter of 2020 compared to $5.2 million, or 0.36 percent of average loans, for the same period in 2019. The most significant charge-off for the first quarter related to a $9.9 million C&I relationship that was charged off due to potential irregularities of the borrower that are still under review. We obtained information on the relationship subsequent to filing our Annual Report on Form 10-K for the year ended December 31, 2019, but before the end of the first quarter of 2020; therefore, we recorded a $9.9 million specific reserve in the day one CECL adjustment. The updated information supported a loss existed at January 1, 2020. Nonperforming loans increased $25.8 million to $73.8 million at March 31, 2020 compared to $48.0 million at March 31, 2019. The significant increase in nonperforming loans primarily related to the addition of a $20.9 million CRE relationship and a $5.9 million C&I relationship, which was partially offset by the $9.9 million C&I relationship that was charged off during the quarter. The $20.9 million CRE relationship became a performing TDR in the third quarter of 2019 and then moved to nonperforming in the first quarter of 2020 when the borrower experienced financial deterioration that lead to cash flow issues. The relationship was individually assessed at March 31, 2020 resulting in no ACL due to the borrower being current on their payments under the modified terms and the relationship being fully collateralized as of March 31, 2020 or as of the filing date of this Form 10-Q.
.
Noninterest Income

| Three Months Ended March 31,
(dollars in thousands) | 2020 |  | 2019 |  | $ Change |  | % Change |
Net gain on sale of securities |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | — |
Service charges on deposit accounts |  | 3,558 |  |  | 3,153 |  |  | 405 |  |  | 12.8 | %
Debit and credit card |  | 3,482 |  |  | 2,974 |  |  | 508 |  |  | 17.1 | %
Commercial loan swap income |  | 2,484 |  |  | 581 |  |  | 1,903 |  |  | 327.5 | %
Wealth management |  | 2,362 |  |  | 2,048 |  |  | 314 |  |  | 15.3 | %
Mortgage banking |  | 1,236 |  |  | 494 |  |  | 742 |  |  | 150.2 | %
Other |  | (719 | ) |  | 2,112 |  |  | (2,831 | ) |  | (134.0 | )%
Total Noninterest Income |  | $ | 12,403 |  |  | $ | 11,362 |  |  | $ | 1,041 |  |  | 9.2 | %

NM - not meaningful
Noninterest income increased $1.0 million to $12.4 million for the three months ended March 31, 2020 compared to the same period in 2019. Total noninterest income includes the impact of the DNB merger in the three months ended March 31, 2020 which closed on November 30, 2019. The increase was also related to higher commercial loan swap income of $1.9 million due to an increase in customer demand for this product in the current interest rate environment. Mortgage banking fees increased $0.7 million due to an increase in the volume of loans originated for sale in the secondary market due to a decline in mortgage rates from the comparable period. Debit and credit card fees also increased $0.5 million compared to 2019 due to increased debit card usage, the DNB merger and the timing of referral merchant revenue. Offsetting these increases was a $2.8 million decrease in other income primarily attributable to the decline in stock market performance during the first quarter of 2020 resulting in a change in the valuation related to a deferred compensation plan of $1.8 million, which has a corresponding
offset in salaries and benefit expense resulting in no impact to net income and a decrease in the equity securities portfolio of $1.3 million compared to the prior period.
51

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
Noninterest Expense

| Three Months Ended March 31,
(dollars in thousands) | 2020 |  | 2019 |  | $ Change |  | % Change |
Salaries and employee benefits(1) |  | $ | 21,335 |  |  | $ | 20,910 |  |  | $ | 425 |  |  | 2.0 | %
Data processing and information technology(1) |  | 3,868 |  |  | 3,233 |  |  | 635 |  |  | 19.6 | %
Net occupancy(1) |  | 3,765 |  |  | 3,036 |  |  | 729 |  |  | 24.0 | %
Furniture, equipment and software(1) |  | 2,519 |  |  | 2,230 |  |  | 289 |  |  | 13.0 | %
Merger related expenses |  | 2,342 |  |  | — |  |  | 2,342 |  |  | NM |
Other taxes |  | 1,600 |  |  | 1,185 |  |  | 415 |  |  | 35.0 | %
Marketing(1) |  | 1,111 |  |  | 1,141 |  |  | (30 | ) |  | (2.6 | )%
Professional services and legal(1) |  | 1,048 |  |  | 1,184 |  |  | (136 | ) |  | (11.5 | )%
FDIC insurance |  | 770 |  |  | 516 |  |  | 254 |  |  | 49.2 | %
Other(1) |  | 8,033 |  |  | 5,449 |  |  | 2,584 |  |  | 47.4 | %
Total Noninterest Expense |  | $ | 46,391 |  |  | $ | 38,884 |  |  | $ | 7,507 |  |  | 19.3 | %

(1)Excludes Merger related expenses for 2020 amounts only.
NM - not meaningful
Noninterest expense increased $7.5 million, or 19.3 percent, to $46.4 million in 2020 compared to 2019. Total noninterest expense includes the impact of the DNB merger in the three months ended March 31, 2020 which closed on November 30, 2019. Total merger related expenses of $2.3 million incurred in the three months ended March 31, 2020 included $1.4 million of salaries and employee benefits, $0.4 million for data processing, $0.2 million for professional services and $0.3 million in various other expenses. Other noninterest expense increased $2.6 million mainly due to $1.1 million increase related to historic tax credits and $0.5 million additional amortization related to the DNB merger. Net occupancy expenses increased $0.7 million due to additional locations acquired as part of the DNB merger. Salaries and employee benefits increased $0.4 million primarily due to additional employees. Data processing and information technology increased $0.6 million due to the outsourcing agreement for certain components of our information technology function, the annual increase with our third-party data processor and the merger. Other taxes increased $0.4 million due to the merger and growth resulting in an increase in our shares tax.
Provision for Income Taxes
The provision for income taxes decreased $1.5 million to $2.7 million for the three months ended March 31, 2020 compared to $4.2 million in the same period in 2019 as a result of the decrease in pretax income of $11.2 million. Our effective tax rate increased to 17.3 percent for the three months ended March 31, 2020 compared to 15.6 percent for the same period in 2019. The increase in the effective tax rate is primarily due to a $1.7 million decrease in tax benefits from tax credits compared to 2019.
Financial Condition as of March 31, 2020
Total assets increased $0.2 billion to $9.0 billion at March 31, 2020 compared $8.8 billion at December 31, 2019. Total portfolio loans increased $109.6 million to $7.2 billion at March 31, 2020 compared to $7.1 billion at December 31, 2019. The increase in portfolio loans primarily related to growth in the commercial loan portfolio of $107.6 million with increases of $60.5 million in C&I, $26.0 million in CRE and $21.1 million in commercial construction compared to December 31, 2019. Consumer loans increased $2.0 million compared to December 31, 2019 with increases in all categories except residential mortgages. Home equity increased $6.1 million, consumer construction loans increased $4.8 million, installment and other consumer increased $0.9 million offset by a decrease of $9.8 million in residential mortgages.
Securities increased $15.2 million to $799.5 million at March 31, 2020 from $784.3 million at December 31, 2019. The increase in securities is primarily due to increases in the unrealized gains of $21.6 million during the three months ended March 31, 2020 partially offset by pay downs on mortgage-backed securities. The bond portfolio had an unrealized gain of $32.3 million at March 31, 2020 compared to $10.7 million at December 31, 2019 due to a decrease in interest rates.
Our deposits increased $21.3 million, with total deposits of $7.1 billion at March 31, 2020 compared to $7.0 billion at December 31, 2019. Customer deposits increased $37.3 million from December 31, 2019. Money market deposits increased $17.9 million, certificates of deposit increased $8.5 million, savings increased $5.3 million, noninterest-bearing demand deposits increased $4.9 million, and interest-bearing demand increased $0.7 million. Total brokered deposits decreased $16.0 million from December 31, 2019. Brokered deposits are an additional source of funds utilized by ALCO as a way to diversify funding sources, as well as manage our funding costs and structure.
Total borrowings increased $177.8 million, or 42.7 percent, compared to December 31, 2019 to fund asset growth. Total short-term borrowings increased by $128.9 million, or 45.8 percent compared to December 31, 2019. Securities sold under repurchase agreements increased $49.8 million to $69.6 million at March 31, 2020 compared to December 31, 2019 due to repositioning by our REPO customers,
Total shareholders’ equity decreased by $15.8 million and remains at $1.2 billion at March 31, 2020 compared to $1.2 billion at December 31, 2019. The decrease was primarily due to the $22.6 million cumulative-effect adjustment related to the adoption of ASU 2016-13, share repurchases of $12.6 million and $11.1 million of dividends partially offset by net income of $13.2 million and $17.3 million increase in other comprehensive income. The increase in other comprehensive income was due to a $17.0 million increase in unrealized gains on our available-for-sale investment securities, net of tax, and a $0.3 million change in the funded status of our employee benefit plans.
Securities Activity

(dollars in thousands) | March 31, 2020 |  |  | December 31, 2019 |  |  | $ Change |
U.S. treasury securities |  | $ | 10,372 |  |  |  | $ | 10,040 |  |  |  | $ | 332 |
Obligations of U.S. government corporations and agencies |  | 137,982 |  |  |  | 157,697 |  |  |  | (19,715 | )
Collateralized mortgage obligations of U.S. government corporations and agencies |  | 189,472 |  |  |  | 189,348 |  |  |  | 124 |
Residential mortgage-backed securities of U.S. government corporations and agencies |  | 21,193 |  |  |  | 22,418 |  |  |  | (1,225 | )
Commercial mortgage-backed securities of U.S. government corporations and agencies |  | 284,679 |  |  |  | 275,870 |  |  |  | 8,809 |
Corporate obligations |  | 7,551 |  |  |  | 7,627 |  |  |  | (76 | )
Obligations of states and political subdivisions |  | 144,717 |  |  |  | 116,133 |  |  |  | 28,584 |
Available-for-Sale Debt Securities |  | 795,966 |  |  |  | 779,133 |  |  |  | 16,833 |
Marketable equity securities |  | 3,566 |  |  |  | 5,150 |  |  |  | (1,584 | )
Total Securities |  | $ | 799,532 |  |  |  | $ | 784,283 |  |  |  | $ | 15,249 |

We invest in various securities in order to maintain a source of liquidity, to satisfy various pledging requirements, to increase net interest income, and as a tool of ALCO to reposition the balance sheet for interest rate risk purposes. Securities are subject to market risks that could negatively affect the level of liquidity available to us. Security purchases are subject to an investment policy approved annually by our Board of Directors and administered through ALCO and our treasury function. Securities increased $15.2 million to $799.5 million at March 31, 2020 from $784.3 million at December 31, 2019. The increase in securities is primarily due to an increase in market value compared to December 31, 2019.
At March 31, 2020 our bond portfolio was in a net unrealized gain position of $32.3 million compared to a net unrealized gain position of $10.7 million at December 31, 2019. At March 31, 2020 total gross unrealized gains in the bond portfolio were $32.3 million compared to December 31, 2019, when total gross unrealized gains were $11.7 million offset by gross unrealized losses of $1.0 million. Management evaluates the securities portfolio to determine if an ACL is needed each quarter. During the three months ended March 31, 2020 we did not record an ACL related to the securities portfolio.
Loan Composition

| March 31, 2020 |  |  | December 31, 2019
(dollars in thousands) | Amount | % of Loans |  |  | Amount | % of Loans
Commercial |  |  |  |  |  |
Commercial real estate | $ | 3,442,495 |  | 47.50 | % |  |  | $ | 3,416,518 |  | 47.87 | %
Commercial and industrial | 1,781,402 |  | 24.58 |  |  |  | 1,720,833 |  | 24.11 |
Construction | 396,518 |  | 5.47 |  |  |  | 375,445 |  | 5.26 |
Total Commercial Loans | 5,620,415 |  | 77.56 | % |  |  | 5,512,796 |  | 77.24 | %
Consumer |  |  |  |  |  |
Residential mortgage | 988,816 |  | 13.64 | % |  |  | 998,585 |  | 13.99 | %
Home equity | 544,405 |  | 7.51 |  |  |  | 538,348 |  | 7.54 |
Installment and other consumer | 79,887 |  | 1.10 |  |  |  | 79,033 |  | 1.10 |
Construction | 13,222 |  | 0.18 |  |  |  | 8,390 |  | 0.12 |
Total Consumer Loans | 1,626,329 |  | 22.44 | % |  |  | 1,624,356 |  | 22.76 | %
Total Portfolio Loans | 7,246,745 |  | 100.00 | % |  |  | 7,137,152 |  | 100.00 | %
Loans held for sale | 7,309 |  |  |  |  | 5,256 |  |
Total Loans | $ | 7,254,054 |  |  |  |  | $ | 7,142,408 |  |

The loan portfolio represents the most significant source of interest income for us. The risk that borrowers will be unable to pay such obligations is inherent in the loan portfolio. Other conditions such as downturns in the borrower’s industry or the overall economic climate can significantly impact the borrower’s ability to pay.
52

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
Commercial loans, including CRE, C&I and commercial construction, comprised 77.6 percent of total portfolio loans at March 31, 2020 and 77.2 percent at December 31, 2019. Total portfolio loans increased $109.6 million to $7.2 billion at March 31, 2020 compared to $7.1 billion at December 31, 2019. The increase of $107.6 million in the commercial loans related to $60.5 million in C&I, $26.0 million in CRE and $21.1 million in commercial construction loans compared to December 31, 2019.
Consumer loans represent 22.4 percent of our total portfolio loans at March 31, 2020 and 22.8 percent at December 31, 2019. Consumer loans increased $2.0 million compared to December 31, 2019 with increases in all categories except residential mortgages. Home equity increased $6.1 million, consumer construction loans increased $4.8 million, installment and other consumer increased $0.9 million offset by a decrease of $9.8 million in residential mortgages.
Allowance for Credit Losses
We maintain an ACL at a level determined to be adequate to absorb estimated expected credit losses within the loan portfolio over the contractual life of a loan that considers our historical loss experience, current conditions and forecasts of future economic conditions as of the balance sheet date. We develop and document a systematic ACL methodology based on the following portfolio segments: 1) Construction, 2) CRE, 3) C&I, 4) Business Banking, 5) Consumer Real Estate and 6) Other Consumer.
The following are key risks within each portfolio segment:
CRE—Loans secured by commercial purpose real estate, including both owner-occupied properties and investment properties for various purposes such as hotels, retail, multifamily, and healthcare. Operations of the individual projects and global cash flows of the debtors are the primary sources of repayment for these loans. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the collateral type and the business prospects of the lessee, if the project is not owner-occupied.
C&I—Loans made to operating companies or manufacturers for the purpose of production, operating capacity, accounts receivable, inventory or equipment financing. Cash flow from the operations of the company is the primary source of repayment for these loans. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the industry of the company. Collateral for these types of loans often does not have sufficient value in a distressed or liquidation scenario to satisfy the outstanding debt.
53

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
Commercial Construction—Loans made to finance construction of buildings or other structures, as well as to finance the acquisition and development of raw land for various purposes. While the risk of these loans is generally confined to the construction period, if there are problems, the project may not be completed, and as such, may not provide sufficient cash flow on its own to service the debt or have sufficient value in a liquidation to cover the outstanding principal. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the type of project and the experience and resources of the developer.
Business Banking—Commercial loans made to small businesses that are standard, non-complex products evaluated through a streamlined credit approval process that has been designed to maximize efficiency while maintaining high credit quality standards that meet small business market customers’ needs. The business banking portfolio is monitored by utilizing a standard and closely managed process focusing on behavioral and performance criteria. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the collateral type and business.
Consumer Real Estate—Loans secured by first and second liens such as home equity loans, home equity lines of credit and 1-4 family residential mortgages, including purchase money mortgages. The primary source of repayment for these loans is the income and assets of the borrower. The condition of the local economy, in particular the unemployment rate, is an important indicator of risk for this segment. The state of the local housing market can also have a significant impact on this segment because low demand and/or declining home values can limit the ability of borrowers to sell a property and satisfy the debt.
Other Consumer—Loans made to individuals that may be secured by assets other than 1-4 family residences, as well as unsecured loans. This segment includes auto loans, unsecured loans and lines and credit cards. The primary source of repayment for these loans is the income and assets of the borrower. The condition of the local economy, in particular the unemployment rate, is an important indicator of risk for this segment. The value of the collateral, if there is any, is less likely to be a source of repayment due to less certain collateral values.
The following table presents activity in the ACL for the three months ended March 31, 2020:

| Three Months Ended March 31, 2020 |  |
(dollars in thousands) | Commercial Real Estate |  | Commercial and Industrial |  | Commercial Construction |  | Business Banking(1) |  | Consumer Real Estate |  | Other Consumer |  | Total Loans
Three months ended March 31, 2020 |  |  |  |  |  |  |  |  |  |  |  |  |
Allowance for credit losses on loans: |  |  |  |  |  |  |  |  |  |  |  |  |
Balance at beginning of period | $ | 30,577 |  |  | $ | 15,681 |  |  | $ | 7,900 |  |  | $ | — |  |  | $ | 6,337 |  |  | $ | 1,729 |  |  | $ | 62,224 |
Impact of CECL adoption | 4,810 |  |  | 7,853 |  |  | (3,376 | ) |  | 12,898 |  |  | 4,525 |  |  | 642 |  |  | 27,352 |
Provision for credit losses on loans | 7,639 |  |  | 6,196 |  |  | 2,309 |  |  | 1,194 |  |  | 472 |  |  | 620 |  |  | 18,430 |
Charge-offs | (442 | ) |  | (9,879 | ) |  | (229 | ) |  | (460 | ) |  | (172 | ) |  | (248 | ) |  | (11,430 | )
Recoveries | 27 |  |  | 19 |  |  | 2 |  |  | 74 |  |  | 38 |  |  | 114 |  |  | 274 |
Net (Charge-offs)/Recoveries | (415 | ) |  | (9,860 | ) |  | (227 | ) |  | (386 | ) |  | (134 | ) |  | (134 | ) |  | (11,156 | )
Balance at End of Period | $ | 42,611 |  |  | $ | 19,870 |  |  | $ | 6,606 |  |  | $ | 13,706 |  |  | $ | 11,200 |  |  | $ | 2,857 |  |  | $ | 96,850 |

| March 31, 2020 |  |  | December 31, 2019 |
Ratio of net charge-offs to average loans outstanding | 0.63 | % | * | 0.22 | %
Allowance for credit losses as a percentage of total loans | 1.34 | % |  | 0.87 | %
Allowance for credit losses to nonperforming loans | 131 | % |  | 115 | %

* Annualized
(1) In connection with our adoption of ASU 2016-13, we made changes to our loan portfolio segments to align with the methodology applied in determining the allowance under CECL. Our new segmentation breaks out business banking loans from our other loan segments: CRE, C&I , commercial construction, consumer real estate and other consumer. The business banking allowance balance at the beginning of period is included in the other segments and reclassified to business banking through the impact of CECL adoption line.
The adoption of ASU 2016-13 resulted in an increase to our ACL of $27.4 million on January 1, 2020. The increase included $8.2 million for S&T legacy loans and $9.3 million for acquired loans from the DNB merger. We also recorded a day one adjustment of $9.9 million primarily related to a C&I relationship that was charged off in the first quarter of 2020. We obtained information on the relationship subsequent to filing our Annual Report on Form 10-K for the year ended December 31, 2019, but before the end of the first quarter of 2020. The updated information supported that a loss existed at January 1, 2020.
54

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
The significant increase in the provision for credit losses of $18.4 million during the three months ended March 31, 2020 was mainly due to the COVID-19 pandemic. Net loan charge-offs were $11.2 million, or 0.63 percent of average loans, for the three months ended March 31, 2020. The most significant charge-off for the first quarter related to a $9.9 million C&I relationship that was charged off due to potential irregularities of the borrower that are still under review. We obtained information on the relationship subsequent to filing our December 31, 2019 10-K, but before the end of the first quarter of 2020; therefore, we recorded a day one CECL adjustment through a $9.9 million specific reserve. The updated information supported a loss existed at January 1, 2020.
Commercial substandard loans increased $15.8 million to $168.5 million at March 31, 2020 compared to $152.7 million at December 31, 2019 and special mention loans increased $20.8 million to $124.7 million at March 31, 2020 compared to $103.9 million at December 31, 2019 due to downgrades as a result of updated financial information.
Nonperforming loans increased $19.7 million to $73.8 million at March 31, 2020 compared to $54.1 million at
December 31, 2019. The significant increase in nonperforming loans primarily related to the addition of a $20.9 million CRE relationship and a $5.9 million C&I relationship, which was partially offset by the $9.9 million C&I relationship that was charged off during the quarter. The $20.9 million CRE relationship became a performing TDR in the third quarter of 2019 and then moved to nonperforming in the first quarter of 2020 when the borrower experienced financial deterioration that led to cash flow issues. The relationship was individually assessed at March 31, 2020 resulting in no ACL due to the borrower being current on their payments under the modified terms and the relationship is fully collateralized as of March 31, 2020.
The adoption of the CECL accounting standard as of January 1, 2020 and the uncertainty around the COVID-19 pandemic both contributed to the higher ACL of 1.34 percent of total portfolio loans as of March 31, 2020 compared to 0.87 percent at December 31, 2019.
TDRs increased $5.4 million to $51.3 million at March 31, 2020 compared to $45.9 million at December 31, 2019. Total TDRs of $51.3 million at March 31, 2020 included $15.2 million, or 29.6 percent, that were accruing and $36.1 million, or 70.4 percent, that were not accruing.
Our allowance for credit losses on unfunded commercial lending commitments and letters of credit provide for the risk of expected loss in these arrangements. The allowance is computed using a methodology similar to that used to determine the ACL for loans, modified to take into account the probability of a draw-down on the commitment. The provision for credit losses on unfunded loan commitments is included in the provision for credit losses on our consolidated statement of comprehensive income. The allowance for unfunded loan commitments was $6.1 million at March 31, 2020 compared to $3.1 million at December 31, 2019. The adoption of ASU 2016-13 resulted in an increase to our allowance for unfunded commitments of $1.4 million on January 1, 2020. We increased the allowance for unfunded loan commitments $1.6 million during the three months ended March 31, 2020 mainly in response to COVID-19 pandemic. The allowance for unfunded commitments is included in other liabilities in the Consolidated Balance Sheets.
55

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
Nonperforming assets consist of nonaccrual loans, nonaccrual TDRs and OREO. The following table summarizes nonperforming assets for the dates presented:

(dollars in thousands) | March 31, 2020 |  |  | December 31, 2019 |  |  | $ Change |
Nonperforming Loans |  |  |  |  |  |  |  |
Commercial real estate |  | $ | 21,267 |  |  |  | $ | 22,427 |  |  |  | $ | (1,160 | )
Commercial and industrial |  | 4,348 |  |  |  | 13,287 |  |  |  | (8,939 | )
Commercial construction |  | 571 |  |  |  | 737 |  |  |  | (166 | )
Residential mortgage |  | 9,271 |  |  |  | 6,697 |  |  |  | 2,574 |
Home equity |  | 2,029 |  |  |  | 1,961 |  |  |  | 68 |
Installment and other consumer |  | 258 |  |  |  | 36 |  |  |  | 222 |
Total Nonperforming Loans |  | 37,744 |  |  |  | 45,145 |  |  |  | (7,400 | )
Nonperforming Troubled Debt Restructurings |  |  |  |  |  |  |  |
Commercial real estate |  | 29,242 |  |  |  | 6,713 |  |  |  | 22,529 |
Commercial and industrial |  | 4,734 |  |  |  | 695 |  |  |  | 4,039 |
Commercial construction |  | — |  |  |  | — |  |  |  | — |
Residential mortgage |  | 1,311 |  |  |  | 822 |  |  |  | 489 |
Home equity |  | 768 |  |  |  | 678 |  |  |  | 90 |
Installment and other consumer |  | — |  |  |  | 4 |  |  |  | (4 | )
Total Nonperforming Troubled Debt Restructurings |  | 36,055 |  |  |  | 8,912 |  |  |  | 27,142 |
Total Nonperforming Loans |  | 73,799 |  |  |  | 54,057 |  |  |  | 19,742 |
OREO |  | 3,389 |  |  |  | 3,525 |  |  |  | (136 | )
Total Nonperforming Assets |  | $ | 77,188 |  |  |  | $ | 57,582 |  |  |  | $ | 19,606 |
Asset Quality Ratios: |  |  |  |  |  |  |  |
Nonperforming loans as a percent of total loans |  | 1.02 | % |  |  | 0.76 | % |  |  |
Nonperforming assets as a percent of total loans plus OREO |  | 1.06 | % |  |  | 0.81 | % |  |  |

Our policy is to place loans in all categories in nonaccrual status when collection of interest or principal is doubtful, or generally when interest or principal payments are 90 days or more past due.
Nonperforming loans increased $19.7 million to $73.8 million at March 31, 2020 compared to $54.1 million at
December 31, 2019 mainly due to the $20.9 million CRE relationship discussed above.
Deposits

(dollars in thousands) | March 31, 2020 |  |  | December 31, 2019 |  |  | $ Change |
Customer Deposits |  |  |  |  |  |  |  |
Noninterest-bearing demand |  | $ | 1,702,960 |  |  |  | $ | 1,698,082 |  |  |  | $ | 4,878 |
Interest-bearing demand |  | 762,783 |  |  |  | 762,111 |  |  |  | 672 |
Money market |  | 1,867,602 |  |  |  | 1,849,684 |  |  |  | 17,918 |
Savings |  | 836,237 |  |  |  | 830,919 |  |  |  | 5,318 |
Certificates of deposit |  | 1,543,790 |  |  |  | 1,535,305 |  |  |  | 8,485 |
Total Customer Deposits |  | 6,713,371 |  |  |  | 6,676,101 |  |  |  | 37,271 |
Brokered Deposits |  |  |  |  |  |  |  |
Interest-bearing demand |  | 200,154 |  |  |  | 200,220 |  |  |  | (66 | )
Money market |  | 100,090 |  |  |  | 100,127 |  |  |  | (37 | )
Certificates of deposit |  | 44,263 |  |  |  | 60,128 |  |  |  | (15,865 | )
Total Brokered Deposits |  | 344,507 |  |  |  | 360,475 |  |  |  | (15,969 | )
Total Deposits |  | $ | 7,057,879 |  |  |  | $ | 7,036,576 |  |  |  | $ | 21,303 |

56

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
Deposits are our primary source of funds. We believe that our deposit base is stable and that we have the ability to attract new deposits. Total deposits at March 31, 2020 increased $21.3 million from December 31, 2019. Total customer deposits increased $37.3 million from December 31, 2019. Money market deposits increased $17.9 million, certificates of deposit increased $8.5 million, savings increased $5.3 million, noninterest-bearing demand deposits increased $4.9 million, and interest-bearing demand increased $0.7 million. Total brokered deposits decreased $16.0 million from December 31, 2019. Brokered deposits are an additional source of funds utilized by ALCO as a way to diversify funding sources, as well as manage our funding costs and structure.
Borrowings

(dollars in thousands) | March 31, 2020 |  |  | December 31, 2019 |  |  | $ Change |
Securities sold under repurchase agreements |  | $ | 69,644 |  |  |  | $ | 19,888 |  |  |  | $ | 49,756 |
Short-term borrowings |  | 410,240 |  |  |  | 281,319 |  |  |  | 128,921 |
Long-term borrowings |  | 50,180 |  |  |  | 50,868 |  |  |  | (688 | )
Junior subordinated debt securities |  | 64,038 |  |  |  | 64,277 |  |  |  | (239 | )
Total Borrowings |  | $ | 594,102 |  |  |  | $ | 416,352 |  |  |  | $ | 177,750 |

Borrowings are an additional source of funding for us. At March 31, 2020 total borrowings increased $177.8 million, or 42.7 percent, compared to December 31, 2019 to fund asset growth. Total short-term borrowings increased by $128.9 million, or 45.8 percent, compared to December 31, 2019. Securities sold under repurchase agreements increased $49.8 million to $69.6 million during the three month period compared to December 31, 2019 due to repositioning by our REPO customers.
Information pertaining to short-term borrowings is summarized in the tables below for the three months ended March 31, 2020 and for the twelve months ended December 31, 2019.

| Securities Sold Under Repurchase Agreements
(dollars in thousands) | March 31, 2020 |  | December 31, 2019
Balance at the period end | $ | 69,644 |  |  | $ | 19,888 |
Average balance during the period | $ | 30,790 |  |  | $ | 16,863 |
Average interest rate during the period | 0.56 | % |  | 0.65 | %
Maximum month-end balance during the period | $ | 69,644 |  |  | $ | 23,427 |
Average interest rate at the period end | 0.25 | % |  | 0.74 | %
| Short-Term Borrowings
(dollars in thousands) | March 31, 2020 |  | December 31, 2019
Balance at the period end | $ | 410,240 |  |  | $ | 281,319 |
Average balance during the period | $ | 286,365 |  |  | $ | 255,264 |
Average interest rate during the period | 1.61 | % |  | 2.51 | %
Maximum month-end balance during the period | $ | 410,240 |  |  | $ | 425,000 |
Average interest rate at the period end | 0.44 | % |  | 1.84 | %

Information pertaining to long-term borrowings is summarized in the tables below for the three months ended March 31, 2020 and for the twelve months ended December 31, 2019.

| Long-Term Borrowings
(dollars in thousands) | March 31, 2020 |  | December 31, 2019
Balance at the period end | $ | 50,180 |  |  | $ | 50,868 |
Average balance during the period | $ | 51,845 |  |  | $ | 66,392 |
Average interest rate during the period | 2.52 | % |  | 2.76 | %
Maximum month-end balance during the period | $ | 50,635 |  |  | $ | 70,418 |
Average interest rate at the period end | 2.59 | % |  | 2.61 | %
| Junior Subordinated Debt Securities
(dollars in thousands) | March 31, 2020 |  | December 31, 2019
Balance at the period end | $ | 64,038 |  |  | $ | 64,277 |
Average balance during the period | $ | 64,195 |  |  | $ | 47,934 |
Average interest rate during the period | 4.40 | % |  | 4.82 | %
Maximum month-end balance during the period | $ | 64,648 |  |  | $ | 64,277 |
Average interest rate at the period end | 3.63 | % |  | 4.42 | %

57

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
Liquidity and Capital Resources
L iquidity is defined as a financial institution’s ability to meet its cash and collateral obligations at a reasonable cost. This includes the ability to satisfy the financial needs of depositors who want to withdraw funds or of borrowers needing to access funds to meet their credit needs. In order to manage liquidity risk, our Board of Directors has delegated authority to ALCO for the formulation, implementation, and oversight of liquidity risk management for S&T. The ALCO’s goal is to maintain adequate levels of liquidity at a reasonable cost to meet funding needs in both a normal operating environment and for potential liquidity stress events. The ALCO monitors and manages liquidity through various ratios, reviewing cash flow projections, performing stress tests, and having a detailed contingency funding plan. The ALCO policy guidelines define graduated risk tolerance levels. If our liquidity position moves to a level that has been defined as high risk, specific actions are required, such as increased monitoring or the development of an action plan to reduce the risk position.
Our primary funding and liquidity source is a stable customer deposit base. We believe S&T has the ability to retain existing and attract new deposits, mitigating any funding dependency on other more volatile sources. Refer to the "Financial Condition-Deposits" section of this MD&A, for additional discussion on deposits. Although deposits are the primary source of funds, we have identified various other funding sources that can be used as part of our normal funding program when either a structure or cost efficiency has been identified. Additional funding sources accessible to S&T include borrowing availability at the FHLB of Pittsburgh, federal funds lines with other financial institutions, the brokered deposit market, and borrowing availability through the Federal Reserve Borrower-In-Custody program.
An important component of our ability to effectively respond to potential liquidity stress events is maintaining a cushion of highly liquid assets. Highly liquid assets are those that can be converted to cash quickly, with little or no loss in value, to meet financial obligations. ALCO policy guidelines define a ratio of highly liquid assets to total assets by graduated risk tolerance levels of minimal, moderate, and high. At March 31, 2020, we had $618.0 million in highly liquid assets, which consisted of $113.2 million in interest-bearing deposits with banks, $497.5 million in unpledged securities and $7.3 million in loans held for sale. This resulted in a highly liquid assets to total assets ratio of 6.9 percent at March 31, 2020. Also, at March 31, 2020, we had a remaining borrowing availability of $2.4 billion with the FHLB of Pittsburgh. Refer to Note 9:, Borrowings in the Notes to Consolidated Financial Statements and the "Financial Condition- Borrowings" section of this MD&A for more details.
The following table summarizes capital amounts and ratios for S&T and S&T Bank for the dates presented:

(dollars in thousands) | Adequately Capitalized | Well- Capitalized |  | March 31, 2020 |  | December 31, 2019
| Amount | Ratio |  | Amount | Ratio
S&T Bancorp, Inc. |  |  |  |  |  |  |  |
Tier 1 leverage | 4.00 | % | 5.00 | % |  | $ | 843,703 |  | 10.03 | % |  | $ | 854,146 |  | 10.29 | %
Common equity tier 1 to risk-weighted assets | 4.50 | % | 6.50 | % |  | 814,703 |  | 10.93 | % |  | 825,146 |  | 11.43 | %
Tier 1 capital to risk-weighted assets | 6.00 | % | 8.00 | % |  | 843,703 |  | 11.32 | % |  | 854,146 |  | 11.84 | %
Total capital to risk-weighted assets | 8.00 | % | 10.00 | % |  | 948,509 |  | 12.73 | % |  | 954,094 |  | 13.22 | %
S&T Bank |  |  |  |  |  |  |  |
Tier 1 leverage | 4.00 | % | 5.00 | % |  | $ | 821,488 |  | 9.79 | % |  | $ | 832,113 |  | 10.04 | %
Common equity tier 1 to risk-weighted assets | 4.50 | % | 6.50 | % |  | 821,488 |  | 11.04 | % |  | 832,113 |  | 11.56 | %
Tier 1 capital to risk-weighted assets | 6.00 | % | 8.00 | % |  | 821,488 |  | 11.04 | % |  | 832,113 |  | 11.56 | %
Total capital to risk-weighted assets | 8.00 | % | 10.00 | % |  | 918,495 |  | 12.35 | % |  | 922,310 |  | 12.81 | %

We have filed a shelf registration statement on Form S-3 under the Securities Act of 1933, as amended, with the SEC, which allows for the issuance of a variety of securities including debt and capital securities, preferred and common stock and warrants. We may use the proceeds from the sale of securities for general corporate purposes, which could include investments at the holding company level, investing in, or extending credit to subsidiaries, possible acquisitions and stock repurchases. As of March 31, 2020, we had not issued any securities pursuant to this shelf registration statement.
S&T is monitoring and will continue to monitor the impact of the COVID-19 pandemic and has taken and will continue to take steps to mitigate the potential risks and impact on our liquidity and capital resources. Due to the economic uncertainty, we are taking a prudent approach to capital management and have established access to the Federal Reserve’s PPP Lending Facility.
58

Table of Contents
Item 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK
Market risk is defined as the degree to which changes in interest rates, foreign exchange rates, commodity prices, or equity prices can adversely affect a financial institution’s earnings or capital. For most financial institutions, including S&T, market risk primarily reflects exposures to changes in interest rates. Interest rate fluctuations affect earnings by changing net interest income and other interest-sensitive income and expense levels. Interest rate changes also affect capital by changing the net present value of a bank’s future cash flows, and the cash flows themselves, as rates change. Accepting this risk is a normal part of banking and can be an important source of profitability and enhancing shareholder value. However, excessive interest rate risk can threaten a bank’s earnings, capital, liquidity and solvency. Our sensitivity to changes in interest rate movements is continually monitored by ALCO. ALCO monitors and manages market risk through rate shock analyses, economic value of equity, or EVE, analyses and by performing stress tests and simulations in order to mitigate earnings and market value fluctuations due to changes in interest rates.
Rate shock analyses results are compared to a base case to provide an estimate of the impact that market rate changes may have on 12 and 24 months of pretax net interest income. The base case and rate shock analyses are performed on a static balance sheet. A static balance sheet is a no growth balance sheet in which all maturing and/or repricing cash flows are reinvested in the same product at the existing product spread. Rate shock analyses assume an immediate parallel shift in market interest rates and also include management assumptions regarding the impact of interest rate changes on non-maturity deposit products (noninterest-bearing demand, interest-bearing demand, money market and savings) and changes in the prepayment behavior of loans and securities with optionality. S&T policy guidelines limit the change in pretax net interest income over 12 and 24 month horizons using rate shocks in increments of +/- 100 basis points. Policy guidelines define the percentage change in pretax net interest income by graduated risk tolerance levels of minimal, moderate and high. We have temporarily suspended the analyses on downward rate shocks of 200 basis points or more because they do not provide meaningful insight into our interest rate risk position.
In order to monitor interest rate risk beyond the 24 month time horizon of rate shocks on pretax net interest income, we also perform EVE analyses. EVE represents the present value of all asset cash flows minus the present value of all liability cash flows. EVE change results are compared to a base case to determine the impact that market rate changes may have on our EVE. As with rate shock analyses on pretax net interest income, EVE analyses incorporate management assumptions regarding prepayment behavior of fixed rate loans and securities with optionality and the behavior and value of non-maturity deposit products. S&T policy guidelines limit the change in EVE using rate shocks in increments of +/- 100 basis points. Policy guidelines define the percentage change in EVE by graduated risk tolerance levels of minimal, moderate and high. We have also temporarily suspended the downward rate shocks of 200 basis points or more for EVE.
The table below reflects the rate shock analyses results for the 1 - 12 and 13 - 24 month periods of pretax net interest income and EVE. All results are in the minimal risk tolerance level.

| March 31, 2020 |  | December 31, 2019
| 1 - 12 Months |  |  | 13 - 24 Months |  |  | % Change in EVE |  |  | 1 - 12 Months |  |  | 13 - 24 Months |  |  | % Change in EVE |
Change in Interest Rate (basis points) | % Change in Pretax Net Interest Income |  |  | % Change in Pretax Net Interest Income |  |  |  | % Change in Pretax Net Interest Income |  |  | % Change in Pretax Net Interest Income |  |
400 | 10.3 | % |  | 13.5 | % |  | 0.3 | % |  | 9.6 | % |  | 14.4 | % |  | (1.8 | )%
300 | 7.6 |  |  | 10.1 |  |  | 4.6 |  |  | 7.2 |  |  | 10.8 |  |  | 2.8 |
200 | 5.7 |  |  | 7.6 |  |  | 7.6 |  |  | 5.0 |  |  | 7.6 |  |  | 5.5 |
100 | 3.5 |  |  | 4.6 |  |  | 6.9 |  |  | 2.7 |  |  | 4.2 |  |  | 5.1 |
(100) | (8.4 | ) |  | (10.5 | ) |  | (18.5 | ) |  | (4.3 | ) |  | (6.4 | ) |  | (10.8 | )
(200) | NM |  |  | NM |  |  | NM |  |  | — |  |  | — |  |  | — |

NM - not meaningful
The results from the rate shock analyses on pretax net interest income are consistent with having an asset sensitive balance sheet. Having an asset sensitive balance sheet means more assets than liabilities will reprice during the measured time frames. The implications of an asset sensitive balance sheet will differ depending upon the change in market interest rates. For example, with an asset sensitive balance sheet in a declining interest rate environment, more assets than liabilities will decrease in rate. This situation could result in a decrease in net interest income and operating income. Conversely, with an asset sensitive balance sheet in a rising interest rate environment, more assets than liabilities will increase in rate. This situation could result in an increase in net interest income and operating income.
59

Table of Contents
Item 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK
Our rate shock analyses show an improvement in the percentage change in pretax net interest income in the 1-12 month rates up scenarios, a decline in the 13-24 month rates up scenarios, and a decline in the rates down scenarios in months 1 - 12 and 13 - 24 when comparing March 31, 2020 to December 31, 2019. Our EVE analyses show an improvement in the percentage change in EVE in the rates up scenarios and a decline in the rates down scenario when comparing March 31, 2020 to December 31, 2019.
In addition to rate shocks and EVE analyses, we perform a market risk stress test at least annually. The market risk stress test includes sensitivity analyses and simulations. Sensitivity analyses are performed to help us identify which model assumptions cause the greatest impact on pretax net interest income. Sensitivity analyses may include changing prepayment behavior of loans and securities with optionality and the impact of interest rate changes on non-maturity deposit products. Simulation analyses may include the potential impact of rate changes other than the policy guidelines, yield curve shape changes, significant balance mix changes and various growth scenarios.
Item 4. CONTROLS AND PROCEDURES
Evaluation of Disclosure Controls and Procedures
Under the supervision and with the participation of S&T’s Chief Executive Officer, or CEO, and Chief Financial Officer, or CFO (its principal executive officer and principal financial officer, respectively), management has evaluated the effectiveness of the design and operation of S&T’s disclosure controls and procedures as of March 31, 2020. In designing and evaluating the disclosure controls and procedures, management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objectives. We maintain disclosure controls and procedures that are designed to ensure that information required to be disclosed by us in the reports that we file or submit under the Securities Exchange Act of 1934, as amended, or the Exchange Act, is recorded, processed, summarized and reported within the time periods required by the Securities and Exchange Commission, or the SEC, and that such information is accumulated and communicated to S&T’s management, including our CEO and CFO, as appropriate to allow timely decisions regarding required disclosure.
Based on and as of the date of such evaluation, our CEO and CFO concluded that the design and operation of our disclosure controls and procedures were effective in all material respects, as of the end of the period covered by this report.
Changes in Internal Control over Financial Reporting
During the quarter ended March 31, 2020, there were no changes made to S&T’s internal control over financial reporting (as defined in Rule 13a-15(f) under the Exchange Act) that materially affected, or are reasonably likely to materially affect, S&T’s internal control over financial reporting.
60

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
PART II
OTHER INFORMATION
Item 1. Legal Proceedings
None
Item 1A. Risk Factors
There have been no material changes to the risk factors that we have previously disclosed in Part I, Item 1A – “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2019, as filed with the SEC on March 2, 2020 other than the risks described below related to COVID-19.
The duration and severity of the COVID-19 pandemic, in our principal area of operations, nationally and globally, could adversely impact S&T’s business, results of operations and financial condition. While it is difficult to predict the impact of the COVID-19 pandemic (or any other outbreak) on the economy and S&T, the future impacts may include, but are not limited to, the following:

• | Our results of operations may be negatively impacted by general economic or business conditions and uncertainty, including the strength of economic conditions in our principal area of operations impacting the demand for our products and services.

• | The low interest rate environment resulting from the Federal Reserve decreasing the Federal Funds target rates will negatively impact our net interest income and net interest margin.

• | Credit losses may be higher and our provision for credit losses may increase, due to deterioration in the financial condition of S&T’s commercial and consumer loan customers.

• | Declining asset and collateral values may necessitate increases in our provision for credit losses and net charge-offs.

• | Expense management will be impacted by the uncertainty of the effects of the pandemic and S&T’s continued efforts to promote the health and safety of our employees, and the customers and communities we serve.

• | S&T’s liquidity and regulatory capital could be adversely impacted.

• | We may have an interruption or cessation of an important service provided by a third-party provider.

• | Any new or revised regulations regarding capital and liquidity adopted in response to the COVID-19 pandemic may require us to maintain materially more capital or liquidity.

• | Investors may have less confidence in the equity markets in general and in financial services industry in particular, which could have a negative impact on S&T’s stock price and resulting market valuation.

To the extent the COVID-19 pandemic continues to adversely affect the global economy it may also increase the likelihood and/or magnitude of other risks described in the Part I, Item IA. “Risk Factors” in S&T’s Annual Report on Form 10-K for the year ended December 31, 2019.
The impact that the COVID-19 pandemic will have on S&T’s credit losses is uncertain, and continued economic uncertainty and deterioration since January 1, 2020 in the forward looking economic forecasts used to estimate credit losses may adversely affect our ACL.
S&T calculates the ACL, using to the CECL accounting standard adopted January 1, 2020. The CECL methodology reflects expected credit losses and requires consideration of a broad range of reasonable and supportable information to form credit loss estimates. The CECL accounting standard bases the measurement of expected credit losses on historical loss experience, current conditions and reasonable and supportable forecasts that affect the collectability of the reported amount. S&T’s ability to assess expected credit losses may be impaired if the models and approaches we use become less predictive of future behaviors. In particular, the reliance on supportable economic forecasts in light of the COVID-19 pandemic has had and is expected to have an impact on the estimates of our ACL. These forecasts have deteriorated since January 1, 2020 and continued adverse economic forecasts and economic uncertainty could adversely affect our ACL.
61

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
Item 2. Unregistered Sales of Equity Securities and Use of Proceeds
Purchases of Equity Securities
The following table is a summary of our purchases of common stock during the first quarter of 2020:

Period |  | Total number of shares purchased |  |  | Average price paid per share |  |  | Total number of shares purchased as part of publicly announced plan(1)) |  |  | Approximate dollar value of shares that may yet be purchased under the plan |
|  |  |  |  |  |  |  |  | $50,000,000 |
01/01/2020 - 01/31/2020 |  | — |  |  | — |  |  | — |  |  | 50,000,000 |
02/01/2020 - 02/29/2020 |  | 96,699 |  |  | 34.97 |  |  | 96,699 |  |  | 46,618,003 |
03/01/2020 - 03/31/2020 |  | 314,731 |  |  | 29.16 |  |  | 314,731 |  |  | 37,441,683 |
Total |  | 411,430 |  |  |  | $30.52 |  |  | 411,430 |  |  |  | $37,441,683 |

(1)On September 16, 2019, our Board of Directors authorized a $50 million share repurchase plan. This repurchase authorization, which is effective through March 31, 2021, permits S&T to repurchase from time to time up to $50 million in aggregate value of shares of S&T's common stock through a combination of open market and privately negotiated repurchases. The specific timing, price and quantity of repurchases will be at the discretion of S&T and will depend on a variety of factors, including general market conditions, the trading price of common stock, legal and contractual requirements, applicable securities laws and S&T's financial performance. The repurchase plan does not obligate us to repurchase any particular number of shares. We expect to fund any repurchases from cash on hand and internally generated funds. Repurchase activity was suspended in March 2020 as the impact of the COVID-19 pandemic spread.
Item 3. Defaults Upon Senior Securities
None
Item 4. Mine Safety Disclosures
Not Applicable
Item 5. Other Information
None
Item 6. Exhibits

2.1 | Agreement and Plan of Merger, dated June 5, 2019, by and between DNB Financial Corporation and S&T Bancorp, Inc. Filed as Exhibit 2.1 to S&T Bancorp, Inc. Current Report on Form 8-K filed on June 5, 2019, and incorporated herein by reference. |
31.1 | Rule 13a-14(a) Certification of the Chief Executive Officer. | Filed herewith
31.2 | Rule 13a-14(a) Certification of the Chief Financial Officer. | Filed herewith
32 | Rule 13a-14(b) Certification of the Chief Executive Officer and Chief Financial Officer. | Filed herewith
101.INS | XBRL Instance Document - the instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document |
101.SCH | XBRL Taxonomy Extension Schema |
101.CAL | XBRL Taxonomy Extension Calculation Linkbase |
101.DEF | XBRL Taxonomy Extension Definition Linkbase |
101.LAB | XBRL Taxonomy Extension Label Linkbase |
101.PRE | XBRL Taxonomy Extension Presentation Linkbase |
104 | Cover Page Interactive Data File ((formatted as Inline XBRL and contained in Exhibits 101)) |

62

Table of Contents
S&T BANCORP, INC. AND SUBSIDIARIES
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

| S&T Bancorp, Inc. (Registrant)
May 8, 2020 | /s Mark Kochvar
| Mark Kochvar Senior Executive Vice President and Chief Financial Officer (Principal Financial Officer and Duly Authorized Signatory)

63