ONE Gas, Inc. (Form: 10-K, Received: 02/22/2024 16:37:55)

0001587732--12-312023FYfalse0.662.6400015877322023-01-012023-12-3100015877322023-06-30iso4217:USD00015877322024-02-16xbrli:shares00015877322023-12-3100015877322022-12-31xbrli:pure00015877322022-01-012022-12-3100015877322021-01-012021-12-310001587732us-gaap:RetainedEarningsMember2023-01-012023-12-31iso4217:USDxbrli:shares00015877322021-12-3100015877322020-12-310001587732us-gaap:CommonStockMember2020-12-310001587732us-gaap:AdditionalPaidInCapitalMember2020-12-310001587732us-gaap:RetainedEarningsMember2020-12-310001587732us-gaap:AccumulatedOtherComprehensiveIncomeMember2020-12-310001587732us-gaap:CommonStockMember2021-01-012021-12-310001587732us-gaap:AdditionalPaidInCapitalMember2021-01-012021-12-310001587732us-gaap:RetainedEarningsMember2021-01-012021-12-310001587732us-gaap:AccumulatedOtherComprehensiveIncomeMember2021-01-012021-12-310001587732us-gaap:CommonStockMember2021-12-310001587732us-gaap:AdditionalPaidInCapitalMember2021-12-310001587732us-gaap:RetainedEarningsMember2021-12-310001587732us-gaap:AccumulatedOtherComprehensiveIncomeMember2021-12-310001587732us-gaap:CommonStockMember2022-01-012022-12-310001587732us-gaap:AdditionalPaidInCapitalMember2022-01-012022-12-310001587732us-gaap:RetainedEarningsMember2022-01-012022-12-310001587732us-gaap:AccumulatedOtherComprehensiveIncomeMember2022-01-012022-12-310001587732us-gaap:CommonStockMember2022-12-310001587732us-gaap:AdditionalPaidInCapitalMember2022-12-310001587732us-gaap:RetainedEarningsMember2022-12-310001587732us-gaap:AccumulatedOtherComprehensiveIncomeMember2022-12-310001587732us-gaap:CommonStockMember2023-01-012023-12-310001587732us-gaap:AdditionalPaidInCapitalMember2023-01-012023-12-310001587732us-gaap:AccumulatedOtherComprehensiveIncomeMember2023-01-012023-12-310001587732us-gaap:CommonStockMember2023-12-310001587732us-gaap:AdditionalPaidInCapitalMember2023-12-310001587732us-gaap:RetainedEarningsMember2023-12-310001587732us-gaap:AccumulatedOtherComprehensiveIncomeMember2023-12-3100015877322022-11-180001587732ogs:KansasGasServiceSecuritizationILLCMember2023-01-012023-12-310001587732ogs:KansasGasServiceSecuritizationILLCMember2022-01-012022-12-310001587732ogs:NaturalgassalestocustomersMember2023-01-012023-12-310001587732ogs:NaturalgassalestocustomersMember2022-01-012022-12-310001587732ogs:NaturalgassalestocustomersMember2021-01-012021-12-310001587732ogs:TransportationrevenuesMember2023-01-012023-12-310001587732ogs:TransportationrevenuesMember2022-01-012022-12-310001587732ogs:TransportationrevenuesMember2021-01-012021-12-310001587732ogs:SecuritizationCustomerChargesMember2023-01-012023-12-310001587732ogs:SecuritizationCustomerChargesMember2022-01-012022-12-310001587732ogs:SecuritizationCustomerChargesMember2021-01-012021-12-310001587732ogs:MiscellaneousrevenuesMember2023-01-012023-12-310001587732ogs:MiscellaneousrevenuesMember2022-01-012022-12-310001587732ogs:MiscellaneousrevenuesMember2021-01-012021-12-310001587732ogs:OtherrevenuesnaturalgassalesrelatedMember2023-01-012023-12-310001587732ogs:OtherrevenuesnaturalgassalesrelatedMember2022-01-012022-12-310001587732ogs:OtherrevenuesnaturalgassalesrelatedMember2021-01-012021-12-310001587732ogs:OtherrevenuesMember2023-01-012023-12-310001587732ogs:OtherrevenuesMember2022-01-012022-12-310001587732ogs:OtherrevenuesMember2021-01-012021-12-310001587732ogs:WinterWeatherEventCostsMember2023-12-310001587732ogs:UnderrecoveredpurchasedgascostsMember2023-12-310001587732us-gaap:PensionCostsMember2023-12-310001587732us-gaap:LossOnReacquiredDebtMember2023-12-310001587732ogs:MGPCostsMemberMember2023-12-310001587732ogs:AdvaloremtaxMember2023-12-310001587732ogs:WeathernormalizationMember2023-12-310001587732ogs:CustomerCreditDeferralsMember2023-12-310001587732ogs:OtherregulatoryassetsMember2023-12-310001587732ogs:IncometaxratechangesMemberDomain2023-12-310001587732ogs:OverrecoveredpurchasedgascostsMember2023-12-310001587732ogs:WinterWeatherEventCostsMember2022-12-310001587732ogs:UnderrecoveredpurchasedgascostsMember2022-12-310001587732us-gaap:PensionCostsMember2022-12-310001587732us-gaap:LossOnReacquiredDebtMember2022-12-310001587732ogs:MGPCostsMemberMember2022-12-310001587732ogs:AdvaloremtaxMember2022-12-310001587732ogs:WeathernormalizationMember2022-12-310001587732ogs:CustomerCreditDeferralsMember2022-12-310001587732ogs:OtherregulatoryassetsMember2022-12-310001587732us-gaap:PensionCostsMember2022-12-310001587732ogs:IncometaxratechangesMemberDomain2022-12-310001587732ogs:OverrecoveredpurchasedgascostsMember2022-12-3100015877322021-02-2800015877322022-08-250001587732ogs:A5.486KGSSISecuritizedUtilityTariffBondsDue2032Member2022-11-1800015877322023-03-310001587732ogs:WestTexasServiceArea2023-12-310001587732ogs:A361SeniorUnsecuredNotesDue2024Member2023-12-310001587732ogs:A361SeniorUnsecuredNotesDue2024Member2022-12-310001587732ogs:A110SeniorUnsecuredNotesDue2024Member2023-12-310001587732ogs:A110SeniorUnsecuredNotesDue2024Member2022-12-310001587732ogs:A510SeniorUnsecuredNotesDue2029Member2023-12-310001587732ogs:A510SeniorUnsecuredNotesDue2029Member2022-12-310001587732ogs:A200SeniorUnsecuredNotesDue2030Member2023-12-310001587732ogs:A200SeniorUnsecuredNotesDue2030Member2022-12-310001587732ogs:A425SeniorUnsecuredNotesDue2032Member2023-12-310001587732ogs:A425SeniorUnsecuredNotesDue2032Member2022-12-310001587732ogs:A4658SeniorUnsecuredNotesDue2044Member2023-12-310001587732ogs:A4658SeniorUnsecuredNotesDue2044Member2022-12-310001587732ogs:A450SeniorUnsecuredNotesDue2048Member2023-12-310001587732ogs:A450SeniorUnsecuredNotesDue2048Member2022-12-310001587732ogs:TotalSeniorUnsecuredNotesMember2023-12-310001587732ogs:TotalSeniorUnsecuredNotesMember2022-12-310001587732ogs:A5.486KGSSISecuritizedUtilityTariffBondsDue2032Member2023-12-310001587732ogs:A5.486KGSSISecuritizedUtilityTariffBondsDue2032Member2022-12-310001587732ogs:A800OtherLongTermDebtMember2023-12-310001587732ogs:A800OtherLongTermDebtMember2022-12-310001587732ogs:KansasGasServiceSecuritizationILLCMember2023-12-310001587732ogs:KansasGasServiceSecuritizationILLCMember2022-12-310001587732ogs:A085SeniorUnsecuredNotesDue2023Member2022-08-252022-08-250001587732ogs:A085SeniorUnsecuredNotesDue2023Member2021-12-310001587732ogs:A110SeniorUnsecuredNotesDue2024Member2022-08-252022-08-250001587732ogs:A110SeniorUnsecuredNotesDue2024Member2021-12-310001587732ogs:FloatingRateSeniorUnsecuredNotesDueMarch2023Member2023-01-012023-03-310001587732ogs:A085SeniorUnsecuredNotesDue2023Member2022-11-182022-11-180001587732ogs:A110SeniorUnsecuredNotesDue2024Member2022-11-182022-11-180001587732ogs:A5.486KGSSISecuritizedUtilityTariffBondsDue2032Member2022-11-182022-11-180001587732srt:MinimumMember2023-12-310001587732srt:MaximumMember2023-12-310001587732ogs:December282023Member2023-12-280001587732ogs:December282023Memberogs:AtTheMarketProgramMember2023-12-280001587732ogs:December282023Memberogs:March2023EquityForwardAgreementMember2023-12-280001587732ogs:December282023Member2023-01-012023-12-310001587732ogs:March2023EquityForwardAgreementMemberogs:December292023Member2023-12-310001587732ogs:March2023EquityForwardAgreementMember2023-12-310001587732ogs:December312024Memberogs:September112023EquityForwardAgreementMember2023-09-300001587732ogs:September152023EquityForwardAgreementDomainogs:December312024Member2023-09-300001587732ogs:December312024Memberogs:AtTheMarketProgramMember2023-06-300001587732ogs:December312024Memberogs:March2023EquityForwardAgreementMember2023-03-310001587732ogs:March2023EquityForwardAgreementMemberogs:December292023Member2023-03-310001587732ogs:AtTheMarketProgramMember2023-12-310001587732ogs:December312024Memberogs:AtTheMarketProgramMember2023-12-310001587732ogs:December312024Memberogs:AtTheMarketProgramMember2023-01-012023-12-310001587732ogs:December312024Memberogs:March2023EquityForwardAgreementMember2023-12-310001587732ogs:December312024Memberogs:March2023EquityForwardAgreementMember2023-01-012023-12-310001587732ogs:December312024Memberogs:September112023EquityForwardAgreementMember2023-12-310001587732ogs:December312024Memberogs:September112023EquityForwardAgreementMember2023-01-012023-12-310001587732ogs:September152023EquityForwardAgreementDomainogs:December312024Member2023-12-310001587732ogs:September152023EquityForwardAgreementDomainogs:December312024Member2023-01-012023-12-310001587732ogs:AtTheMarketProgramMember2022-01-012022-12-310001587732ogs:AtTheMarketProgramMember2023-01-012023-12-3100015877322023-10-012023-12-3100015877322022-10-012022-12-310001587732us-gaap:SubsequentEventMember2024-01-012024-03-310001587732us-gaap:SubsequentEventMember2024-01-012024-12-310001587732us-gaap:RestrictedStockUnitsRSUMember2023-01-012023-12-310001587732us-gaap:RestrictedStockUnitsRSUMember2023-12-310001587732us-gaap:PerformanceSharesMember2023-01-012023-12-310001587732us-gaap:PerformanceSharesMember2023-12-310001587732us-gaap:RestrictedStockUnitsRSUMember2022-12-310001587732us-gaap:RestrictedStockUnitsRSUMember2022-01-012022-12-310001587732us-gaap:RestrictedStockUnitsRSUMember2021-01-012021-12-310001587732us-gaap:RestrictedStockUnitsRSUMember2021-12-310001587732us-gaap:PerformanceSharesMember2022-12-310001587732us-gaap:PerformanceSharesMember2022-01-012022-12-310001587732us-gaap:PerformanceSharesMember2021-01-012021-12-310001587732us-gaap:PerformanceSharesMember2021-12-310001587732us-gaap:EmployeeStockMember2023-12-310001587732us-gaap:EmployeeStockMember2022-12-310001587732us-gaap:EmployeeStockMember2021-12-310001587732us-gaap:EmployeeStockMember2023-01-012023-12-310001587732us-gaap:EmployeeStockMember2022-01-012022-12-310001587732us-gaap:EmployeeStockMember2021-01-012021-12-310001587732us-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732us-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310001587732us-gaap:PensionPlansDefinedBenefitMember2023-01-012023-12-310001587732us-gaap:PensionPlansDefinedBenefitMember2021-01-012021-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-01-012023-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-01-012022-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2021-01-012021-12-310001587732us-gaap:PensionPlansDefinedBenefitMember2022-01-012022-12-310001587732ogs:NonserviceCostsMember2023-12-310001587732ogs:NonserviceCostsMember2022-12-310001587732us-gaap:PensionPlansDefinedBenefitMember2021-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2021-12-3100015877322022-04-300001587732ogs:UltimateTrendRateCurrentYearMember2023-12-310001587732ogs:UltimateTrendRatePriorYearMember2022-12-310001587732ogs:InvestmentGradeBondsMember2023-12-310001587732ogs:USLargeCapEquityMember2023-12-310001587732ogs:AlternativeInvestmentsMember2023-12-310001587732ogs:DevelopedForeignLargeCapEquitiesMember2023-12-310001587732ogs:MidCapEquitiesMember2023-12-310001587732ogs:EmergingMarketEquitiesMember2023-12-310001587732ogs:SmallCapEquitiesMember2023-12-310001587732us-gaap:FixedIncomeFundsMember2023-01-012023-12-310001587732us-gaap:EquitySecuritiesMember2023-01-012023-12-310001587732us-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:EquitySecuritiesMember2023-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:EquitySecuritiesMember2023-12-310001587732us-gaap:FairValueInputsLevel3Memberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:EquitySecuritiesMember2023-12-310001587732us-gaap:PensionPlansDefinedBenefitMemberus-gaap:EquitySecuritiesMember2023-12-310001587732ogs:GovernmentObligationsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732us-gaap:FairValueInputsLevel2Memberogs:GovernmentObligationsMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732ogs:GovernmentObligationsMemberus-gaap:FairValueInputsLevel3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732ogs:GovernmentObligationsMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732ogs:CorporateObligationsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732us-gaap:FairValueInputsLevel2Memberogs:CorporateObligationsMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732ogs:CorporateObligationsMemberus-gaap:FairValueInputsLevel3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732ogs:CorporateObligationsMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732ogs:CashAndMoneyMarketFundsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732us-gaap:FairValueInputsLevel2Memberogs:CashAndMoneyMarketFundsMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732ogs:CashAndMoneyMarketFundsMemberus-gaap:FairValueInputsLevel3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732ogs:CashAndMoneyMarketFundsMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732ogs:InsuranceContractsAndGroupAnnuityContractsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732us-gaap:FairValueInputsLevel2Memberogs:InsuranceContractsAndGroupAnnuityContractsMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732ogs:InsuranceContractsAndGroupAnnuityContractsMemberus-gaap:FairValueInputsLevel3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732ogs:InsuranceContractsAndGroupAnnuityContractsMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732us-gaap:OtherInvestmentsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:OtherInvestmentsMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732us-gaap:OtherInvestmentsMemberus-gaap:FairValueInputsLevel3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732us-gaap:OtherInvestmentsMemberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732us-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732us-gaap:FairValueInputsLevel3Memberus-gaap:PensionPlansDefinedBenefitMember2023-12-310001587732us-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:EquitySecuritiesMember2022-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:EquitySecuritiesMember2022-12-310001587732us-gaap:FairValueInputsLevel3Memberus-gaap:PensionPlansDefinedBenefitMemberus-gaap:EquitySecuritiesMember2022-12-310001587732us-gaap:PensionPlansDefinedBenefitMemberus-gaap:EquitySecuritiesMember2022-12-310001587732ogs:GovernmentObligationsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732us-gaap:FairValueInputsLevel2Memberogs:GovernmentObligationsMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732ogs:GovernmentObligationsMemberus-gaap:FairValueInputsLevel3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732ogs:GovernmentObligationsMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732ogs:CorporateObligationsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732us-gaap:FairValueInputsLevel2Memberogs:CorporateObligationsMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732ogs:CorporateObligationsMemberus-gaap:FairValueInputsLevel3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732ogs:CorporateObligationsMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732ogs:CashAndMoneyMarketFundsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732us-gaap:FairValueInputsLevel2Memberogs:CashAndMoneyMarketFundsMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732ogs:CashAndMoneyMarketFundsMemberus-gaap:FairValueInputsLevel3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732ogs:CashAndMoneyMarketFundsMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732ogs:InsuranceContractsAndGroupAnnuityContractsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732us-gaap:FairValueInputsLevel2Memberogs:InsuranceContractsAndGroupAnnuityContractsMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732ogs:InsuranceContractsAndGroupAnnuityContractsMemberus-gaap:FairValueInputsLevel3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732ogs:InsuranceContractsAndGroupAnnuityContractsMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732us-gaap:OtherInvestmentsMemberus-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:OtherInvestmentsMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732us-gaap:OtherInvestmentsMemberus-gaap:FairValueInputsLevel3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732us-gaap:OtherInvestmentsMemberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732us-gaap:FairValueInputsLevel1Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732us-gaap:FairValueInputsLevel3Memberus-gaap:PensionPlansDefinedBenefitMember2022-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel1Memberus-gaap:EquitySecuritiesMember2023-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:EquitySecuritiesMember2023-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Memberus-gaap:EquitySecuritiesMember2023-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:EquitySecuritiesMember2023-12-310001587732ogs:GovernmentObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel1Member2023-12-310001587732us-gaap:FairValueInputsLevel2Memberogs:GovernmentObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310001587732ogs:GovernmentObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310001587732ogs:GovernmentObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310001587732ogs:CorporateObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel1Member2023-12-310001587732us-gaap:FairValueInputsLevel2Memberogs:CorporateObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310001587732ogs:CorporateObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2023-12-310001587732ogs:CorporateObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2023-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:CashAndMoneyMarketFundsMemberus-gaap:FairValueInputsLevel1Member2023-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:CashAndMoneyMarketFundsMember2023-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:CashAndMoneyMarketFundsMemberus-gaap:FairValueInputsLevel3Member2023-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:CashAndMoneyMarketFundsMember2023-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:InsuranceContractsAndGroupAnnuityContractsMemberus-gaap:FairValueInputsLevel1Member2023-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:InsuranceContractsAndGroupAnnuityContractsMember2023-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:InsuranceContractsAndGroupAnnuityContractsMemberus-gaap:FairValueInputsLevel3Member2023-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:InsuranceContractsAndGroupAnnuityContractsMember2023-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:OtherInvestmentsMemberus-gaap:FairValueInputsLevel1Member2023-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:OtherInvestmentsMember2023-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:OtherInvestmentsMemberus-gaap:FairValueInputsLevel3Member2023-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:OtherInvestmentsMember2023-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel1Memberus-gaap:EquitySecuritiesMember2022-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:EquitySecuritiesMember2022-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Memberus-gaap:EquitySecuritiesMember2022-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:EquitySecuritiesMember2022-12-310001587732ogs:GovernmentObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel1Member2022-12-310001587732us-gaap:FairValueInputsLevel2Memberogs:GovernmentObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310001587732ogs:GovernmentObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310001587732ogs:GovernmentObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310001587732ogs:CorporateObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel1Member2022-12-310001587732us-gaap:FairValueInputsLevel2Memberogs:CorporateObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310001587732ogs:CorporateObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:FairValueInputsLevel3Member2022-12-310001587732ogs:CorporateObligationsMemberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember2022-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:CashAndMoneyMarketFundsMemberus-gaap:FairValueInputsLevel1Member2022-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:CashAndMoneyMarketFundsMember2022-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:CashAndMoneyMarketFundsMemberus-gaap:FairValueInputsLevel3Member2022-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:CashAndMoneyMarketFundsMember2022-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:InsuranceContractsAndGroupAnnuityContractsMemberus-gaap:FairValueInputsLevel1Member2022-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:InsuranceContractsAndGroupAnnuityContractsMember2022-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:InsuranceContractsAndGroupAnnuityContractsMemberus-gaap:FairValueInputsLevel3Member2022-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberogs:InsuranceContractsAndGroupAnnuityContractsMember2022-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:OtherInvestmentsMemberus-gaap:FairValueInputsLevel1Member2022-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:OtherInvestmentsMember2022-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:OtherInvestmentsMemberus-gaap:FairValueInputsLevel3Member2022-12-310001587732us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMemberus-gaap:OtherInvestmentsMember2022-12-310001587732ogs:GrosvenorRegisteredMultiLimitedPartnershipMember2023-12-310001587732ogs:GrosvenorRegisteredMultiLimitedPartnershipMember2023-01-012023-12-310001587732ogs:K2InstitutionalInvestorsIILimitedPartnershipMember2023-12-310001587732ogs:K2InstitutionalInvestorsIILimitedPartnershipMember2023-01-012023-12-310001587732ogs:GrosvenorRegisteredMultiLimitedPartnershipMember2022-12-310001587732ogs:GrosvenorRegisteredMultiLimitedPartnershipMember2022-01-012022-12-310001587732ogs:K2InstitutionalInvestorsIILimitedPartnershipMember2022-12-310001587732ogs:K2InstitutionalInvestorsIILimitedPartnershipMember2022-01-012022-12-310001587732ogs:InsuranceContractsAndGroupAnnuityContractsMemberus-gaap:PensionPlansDefinedBenefitMember2021-12-310001587732us-gaap:OtherInvestmentsMemberus-gaap:PensionPlansDefinedBenefitMember2021-12-310001587732ogs:InsuranceContractsAndGroupAnnuityContractsMemberus-gaap:PensionPlansDefinedBenefitMember2022-01-012022-12-310001587732us-gaap:OtherInvestmentsMemberus-gaap:PensionPlansDefinedBenefitMember2022-01-012022-12-310001587732ogs:InsuranceContractsAndGroupAnnuityContractsMemberus-gaap:PensionPlansDefinedBenefitMember2023-01-012023-12-310001587732us-gaap:OtherInvestmentsMemberus-gaap:PensionPlansDefinedBenefitMember2023-01-012023-12-310001587732ogs:A401kPlanMember2023-01-012023-12-310001587732ogs:A401kPlanMember2022-01-012022-12-310001587732ogs:A401kPlanMember2021-01-012021-12-310001587732us-gaap:DomesticCountryMember2023-12-310001587732us-gaap:StateAndLocalJurisdictionMember2023-12-310001587732ogs:NetperiodiccostotherthanservicecostMember2023-01-012023-12-310001587732ogs:NetperiodiccostotherthanservicecostMember2022-01-012022-12-310001587732ogs:NetperiodiccostotherthanservicecostMember2021-01-012021-12-310001587732ogs:EarningslossesoninvestmentsassociatedwithnonqualifiedemployeebenefitplansMember2023-01-012023-12-310001587732ogs:EarningslossesoninvestmentsassociatedwithnonqualifiedemployeebenefitplansMember2022-01-012022-12-310001587732ogs:EarningslossesoninvestmentsassociatedwithnonqualifiedemployeebenefitplansMember2021-01-012021-12-310001587732ogs:OthernetMember2023-01-012023-12-310001587732ogs:OthernetMember2022-01-012022-12-310001587732ogs:OthernetMember2021-01-012021-12-310001587732us-gaap:GasDistributionEquipmentMemberus-gaap:RegulatedOperationMember2023-12-310001587732us-gaap:GasDistributionEquipmentMemberus-gaap:RegulatedOperationMember2022-12-310001587732us-gaap:GasTransmissionEquipmentMemberus-gaap:RegulatedOperationMember2023-12-310001587732us-gaap:GasTransmissionEquipmentMemberus-gaap:RegulatedOperationMember2022-12-310001587732us-gaap:LandBuildingsAndImprovementsMemberus-gaap:RegulatedOperationMember2023-12-310001587732us-gaap:LandBuildingsAndImprovementsMemberus-gaap:RegulatedOperationMember2022-12-310001587732us-gaap:ConstructionInProgressMemberus-gaap:RegulatedOperationMember2023-12-310001587732us-gaap:ConstructionInProgressMemberus-gaap:RegulatedOperationMember2022-12-310001587732us-gaap:RegulatedOperationMember2022-12-310001587732us-gaap:RegulatedOperationMember2023-12-310001587732srt:MinimumMember2023-01-012023-12-310001587732srt:MinimumMember2021-01-012021-12-310001587732srt:MinimumMember2022-01-012022-12-310001587732srt:MaximumMember2023-01-012023-12-310001587732srt:MaximumMember2022-01-012022-12-310001587732srt:MaximumMember2021-01-012021-12-310001587732us-gaap:RegulatedOperationMember2023-01-012023-12-310001587732us-gaap:RegulatedOperationMember2022-01-012022-12-310001587732us-gaap:RegulatedOperationMember2021-01-012021-12-310001587732us-gaap:SwapMember2023-12-31utr:Bcf0001587732us-gaap:CommodityOptionMember2023-12-310001587732us-gaap:CommodityOptionMember2022-12-310001587732us-gaap:USTreasurySecuritiesMemberus-gaap:OtherAssetsMemberus-gaap:FairValueInputsLevel1Member2023-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:USTreasurySecuritiesMemberus-gaap:OtherAssetsMember2023-12-310001587732us-gaap:USTreasurySecuritiesMemberus-gaap:OtherAssetsMember2023-12-310001587732us-gaap:OtherAssetsMemberus-gaap:CorporateBondSecuritiesMemberus-gaap:FairValueInputsLevel1Member2023-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:OtherAssetsMemberus-gaap:CorporateBondSecuritiesMember2023-12-310001587732us-gaap:OtherAssetsMemberus-gaap:CorporateBondSecuritiesMember2023-12-310001587732us-gaap:FairValueInputsLevel1Memberus-gaap:OtherCurrentAssetsMember2023-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:OtherCurrentAssetsMember2023-12-310001587732us-gaap:OtherCurrentAssetsMember2023-12-310001587732us-gaap:SwapMemberus-gaap:OtherCurrentLiabilitiesMemberus-gaap:FairValueInputsLevel1Member2023-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:SwapMemberus-gaap:OtherCurrentLiabilitiesMember2023-12-310001587732us-gaap:SwapMemberus-gaap:OtherCurrentLiabilitiesMember2023-12-310001587732us-gaap:USTreasurySecuritiesMemberus-gaap:OtherAssetsMemberus-gaap:FairValueInputsLevel1Member2022-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:USTreasurySecuritiesMemberus-gaap:OtherAssetsMember2022-12-310001587732us-gaap:USTreasurySecuritiesMemberus-gaap:OtherAssetsMember2022-12-310001587732us-gaap:OtherAssetsMemberus-gaap:CorporateBondSecuritiesMemberus-gaap:FairValueInputsLevel1Member2022-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:OtherAssetsMemberus-gaap:CorporateBondSecuritiesMember2022-12-310001587732us-gaap:OtherAssetsMemberus-gaap:CorporateBondSecuritiesMember2022-12-310001587732us-gaap:FairValueInputsLevel1Memberus-gaap:OtherCurrentAssetsMember2022-12-310001587732us-gaap:FairValueInputsLevel2Memberus-gaap:OtherCurrentAssetsMember2022-12-310001587732us-gaap:OtherCurrentAssetsMember2022-12-310001587732us-gaap:FairValueInputsLevel2Member2023-12-310001587732us-gaap:FairValueInputsLevel2Member2022-12-31

ONE GAS, INC. PERFORMANCE UNIT AWARD AGREEMENT This Performance Unit Award Agreement (this “Agreement”) is made and entered into as of February 19, 2024 (the “Grant Date”) by and between ONE Gas, Inc., an Oklahoma corporation (the “Company”) and the “Participant” named below. Participant: #ParticipantName# WHEREAS, the Company has adopted the ONE Gas, Inc. Amended and Restated Equity Compensation Plan (2018), as amended from time to time (the “Plan”), pursuant to which Performance Unit Awards may be granted; and WHEREAS, the Executive Compensation Committee of the Board of Directors (the “Committee”) has determined that it is in the best interests of the Company and its shareholders to grant the Performance Unit Award provided for herein. NOW, THEREFORE, the parties hereto, intending to be legally bound, agree as follows: 1. Grant of Performance Units. 1.1 The Company hereby grants to the Participant an award consisting of the number of Performance Units specified below (“Performance Units” or the “Award”) on the terms and conditions set forth in this Agreement and the Plan. Number of Performance Units: #QuantityGranted# The Performance Units are contingently awarded and will be earned if and only to the extent that the performance goal described on Exhibit A (the “Performance Goal”) is met and will be vested and distributable only if other conditions in this Agreement are met. Each Performance Unit represents the right to receive one share of the Company’s common stock (“Share”) or, at the Company’s option, an amount of cash as set forth in Section 6.2, in either case, at the times and subject to the conditions set forth herein. The number of Performance Units set forth above is equal to a target number of Shares that the Participant will earn for 100% achievement of the Performance Goal (the “Target Award”). Capitalized terms that are used but not defined herein have the meanings set forth in the Plan. 1.2 The Performance Units shall be credited to a separate account maintained for the Participant on the books and records of the Company (the “Account”). All amounts credited to the Account shall continue for all purposes to be part of the general assets of the Company. 1.3 For purposes of this Agreement, the term "Performance Period" shall be the period commencing on January 1, 2024 and ending on December 31, 2026. Exhibit 10.9

2 2. Consideration. The Award is granted in consideration of the Participant’s continued employment with the Company. 3. Vesting. 3.1 General. Except as provided in this Section 3, subject to Participant’s continuous employment with the Company during the period beginning on the Grant Date and ending on February 13, 2027 (the “Vesting Date”) and subject to the terms of this Agreement, the Participant shall vest on the Vesting Date in the number of Performance Units, if any, earned upon, and certified following, the attainment of the Performance Goal for the Performance Period. Any Performance Units that do not vest as of the Vesting Date shall be forfeited. Performance Units that vest pursuant to the terms of this Agreement, including Sections 3.2 and 3.3 below, are hereinafter referred to as “Vested Units. Unless and until the Performance Units have vested, Participant will have no right to receive any Shares subject thereto. Prior to the actual delivery of any Shares, the Award will represent an unsecured obligation of the Company, payable only from the Company’s general assets. 3.2 Termination of Employment. If prior to the Vesting Date, the Participant ceases to be employed by the Company on account of the Participant’s Retirement, Total Disability or death, the Participant will vest in a pro-rata portion of the Performance Units as of the Vesting Date if the Performance Goal and requirements of this Agreement are met as of such date. The pro-rata portion of the Performance Units that vest will be determined by multiplying (x) the maximum number of Performance Units in which the Participant could vest, based on the actual level at which the Performance Goal is attained and certified for the Performance Period, as if the Participant remained in the continuous employment of the Company until the Vesting Date, by (y) a fraction, which fraction shall be equal to the number of full calendar months which have elapsed since the Grant Date at the time of such termination of employment divided by the number of months in the Performance Period. If the Participant’s employment with the Company terminates prior to the Vesting Date for any other reason, Participant shall immediately forfeit any and all Performance Units that have not vested or do not vest on or prior to the Participant’s termination date and neither the Company nor any Subsidiary shall have any further obligations to the Participant under this Agreement. For purposes of this Agreement, employment with any Subsidiary of the Company shall be treated as employment with the Company. Likewise, a termination of employment shall not be deemed to occur by reason of a transfer of employment between the Company and any Subsidiary. For purposes of this Agreement: (a) “Retirement” means a voluntary termination of employment of the Participant with the Company by the Participant if at the time of such termination of employment the Participant has both completed five (5) years of service with the Company and attained age fifty (50).

3 (b) “Total Disability” means that the Participant is permanently and totally disabled and unable to engage in any substantial gainful activity by reason of a medically determinable physical or mental impairment which can be expected to result in death or which has lasted or can be expected to last for a continuous period of not less than twelve (12) months, and the Participant has established such disability to the extent and in the manner and form as may be required by the Committee. 3.3 Change in Control. If a Change in Control occurs prior to the Vesting Date and the Participant is employed by the Company at the time of the Change in Control, but subsequently terminates prior to the Vesting Date based on an involuntary termination (without cause) or a voluntary termination with “good reason” within 24 months of the Change in Control date, then the Participant’s Performance Units will vest at the Target Award level on the date of such termination (the “Change in Control Vesting Date”). Good reason includes: • Demotion or material reduction of authority or responsibility; • Material reduction in base salary; • Material reduction in annual incentive or LTI targets; • Relocation of greater than 35 miles; or • Failure of the successor company to assume the change-in-control plan. Notwithstanding the foregoing, the provisions set forth in the Plan applicable to a Change in Control shall apply to the Award, and in the event of a Change in Control, the Committee, in its sole discretion and to the extent permitted by Section 409A, may take such actions as it deems appropriate pursuant to the Plan. For purposes of this Agreement, the term “Change in Control” shall have the same meaning as provided in the Plan unless the Award is or becomes subject to Section 409A, in which event “Change in Control” shall have the meaning provided in Section 409A and the related Treasury Regulations. 3.4 Certification. The Committee shall, within a reasonably practicable time following the end of the Performance Period, certify to the extent, if any, to which the Performance Goal has been achieved with respect to the Performance Period and the number of Performance Units, if any, earned upon attainment of the Performance Goal and subject to Section 3. Such certification shall be final, conclusive and binding on the Participant, and on all other persons, to the maximum extent permitted by law. 4. Transfer Restrictions. 4.1 Except as provided in Section 4.2, during the Performance Period and until such time as the Shares underlying the Vested Units have been issued, the Performance Units, related Shares or the rights relating thereto may not be sold, pledged, assigned, transferred or otherwise

4 disposed of by the Participant in any manner other than by will or by laws of descent and distribution. Except as provided in Section 4.2, any attempt to sell, pledge, assign, transfer or otherwise dispose of the Performance Units, related Shares or the rights relating thereto shall be wholly ineffective and, if any such attempt is made, the Performance Units, related Shares or the rights relating thereto will be forfeited by the Participant and all of the Participant's rights to such units or related Shares shall immediately terminate without any payment or consideration by the Company. 4.2 Notwithstanding the foregoing, the Participant may transfer any part or all of the Participant’s rights in the Performance Units to members of the Participant’s immediate family, or to one or more trusts for the benefit of such immediate family members, or partnerships in which such immediate family members are the only partners if the Participant does not receive any consideration for the transfer. In the event of any such transfer, Performance Units shall continue to be subject to the same terms and conditions otherwise applicable hereunder and under the Plan immediately prior to transfer, except that such rights shall not be further transferable by the transferee inter vivos, except for transfer back to the Participant. For any such transfer to be effective, the Participant must provide prior written notice thereof to the Committee and the Participant shall furnish to the Committee such information as it may request with respect to the transferee and the terms and conditions of any such transfer. For purposes of this Agreement, “immediate family” shall mean the Participant’s spouse, children and grandchildren. 5. Dividend Equivalents. The Participant's Account shall be credited with an amount equal to all ordinary cash dividends (“Dividend Equivalents”) that would have been paid to the Participant if one Share had been issued on the Grant Date for each Performance Unit granted to the Participant as set forth in this Agreement. The Dividend Equivalents credited to the Participant’s Account will be deemed to be reinvested in additional Performance Units (or fractional units) and will be subject to the same terms and conditions as the Performance Units to which they are attributable and shall vest or be forfeited (if applicable) and settled at the same time as the Performance Units to which they are attributable. Such additional Performance Units shall also be credited with additional Dividend Equivalents as any further dividends are declared. No Dividend Equivalents shall be credited with respect to any Performance Units, which as of the record date, have either been settled or forfeited. 6. Time and Form of Payment with Respect to Vested Units. 6.1 Unless an election is made pursuant to Section 7 below and subject to Section 10 and Section 23.2 and subject to certification by the Committee that the Performance Goal has been achieved and other vesting conditions have been satisfied, the Participant will receive a distribution with respect to the Vested Units within 75 days following the earlier of: (i) the Vesting Date (the “Distribution Date”) or (ii) the Change in Control Vesting Date described in

5 Section 3.3. The Vested Units will be settled and distributed in Shares (either in book-entry form or otherwise) or, at the Company’s option, paid in an amount of cash as set forth in Section 6.2. All distributions in Shares shall be in the form of whole Shares, and any fractional Share shall be distributed in cash in an amount equal to the value of such fractional Share determined based on the Fair Market Value of a Share on the Vesting Date or Change in Control Vesting Date, as applicable. 6.2 If the Company elects to settle the Participant’s Vested Units in cash, the amount of cash payable with respect to each Vested Unit shall be equal to the Fair Market Value of a Share on the Vesting Date or Change in Control Vesting Date, as applicable. 6.3 To the extent that the Participant does not vest in any Performance Units on or before the Vesting Date, all interest in such Performance Units and any additional Performance Units attributable to Dividend Equivalents shall be forfeited. The Participant has no right or interest in any Performance Units that are forfeited. 7. Deferral Election for Officers. 7.1 If the Participant is an officer of the Company, the Participant may irrevocably elect to defer the Distribution Date of Performance Units, Shares and cash that the Participant becomes entitled to receive under this Agreement (the “Deferred Amounts”) to a later date, by filing with the Committee, on or before the deferral election date (the “Election Deadline”) described in Section 7.2 below, a signed written irrevocable election (the “Election”) which shall be in the form substantially the same as attached hereto as Exhibit D, or as otherwise approved by the Committee. 7.2 Any such Election shall be filed with the Committee on or before the Election Deadline, which shall be June 30, 2026, the date that is six (6) months before the end of the Performance Period and shall become effective and irrevocable on such date provided that the Participant performs services for the Company continuously from the later of the beginning of the Performance Period or the date the Performance Goal was established through the Election Deadline. Notwithstanding the foregoing, in no event shall the Participant’s Election become effective if any portion of the Deferred Amounts has become readily ascertainable (within the meaning of Section 409A) and is substantially certain to be paid the Participant as of the Election Deadline. To defer the Distribution Date, the Participant must elect to defer one-hundred percent (100%) of the Deferred Amounts. Subject to Section 23.2, the Deferred Amounts shall be distributed to Participant at the time and in the form set forth in the Election (the “Deferred Date”). Notwithstanding a Participant’s Election pursuant to this Section 7, if a Change in Ownership or Control (within the meaning of Section 409A) occurs prior to the Deferred Date, the Deferred Amounts will be distributed to the Participant on the date of the Change in Ownership or Control.

6 7.3 This Section 7 shall be applicable solely to the Award and shall not apply to any other compensation payable to the Participant under the Plan or otherwise. The right to make a deferral election under this Section 7 is expressly limited to officers of the Company or any subset thereof as determined by the Committee from time to time. This Agreement shall not permit a subsequent election to delay or modify the form of payment unless authorized and agreed upon in writing by the Company and Participant and such subsequent election complies with Section 409A. 8. Conditions to Issuance or Transfer of Shares. The issuance and transfer of Shares shall be subject to compliance by the Company and the Participant with all applicable laws, rules and regulations (“Applicable Laws”) and also to such approvals by governmental agencies as may be deemed appropriate to comply with relevant securities laws and regulations. No Shares shall be issued or transferred unless and until any then applicable requirements of Applicable Laws and regulatory agencies have been fully complied with to the satisfaction of the Company and its counsel. 9. Tax Withholding. Participant shall be required to pay to the Company, and the Company shall have the right to deduct from any compensation paid to the Participant pursuant to the Plan, the amount of any required federal, state and local taxes, domestic or foreign, including payroll taxes, in respect of the Award and to take all such other action as the Committee deems necessary to satisfy all obligations for the payment of such withholding taxes. The Company shall have no obligation to issue any Shares to any Participant unless and until the Participant has made arrangements, satisfactory to the Company in its sole discretion, to satisfy the Participant’s tax liability resulting from the vesting or settlement of the Vested Units. The amount of such withholding shall be determined by the Company. The Committee, in its sole discretion, may permit or require the Participant to satisfy any such tax withholding obligation by any of, or a combination of, the following means: 9.1 tendering a cash payment or check payable to the Company. 9.2 authorizing the Company to withhold an amount from any cash amounts otherwise due or to become due from the Company to the Participant. 9.3 authorizing the Company to withhold Shares from the Shares otherwise issuable to the Participant as a result of the vesting of the Performance Units; provided, however, that no Shares shall be withheld with a Fair Market Value exceeding the maximum amount of tax required to be withheld by Applicable law. 9.4 delivering to the Company previously owned and unencumbered Shares having a then current Fair Market Value not exceeding the maximum amount of tax required to be withheld by Applicable Law.

7 10. Rights as Shareholder. Except as otherwise provided in the Agreement, the Participant shall not have any of the rights or privileges of a shareholder with respect to the Shares underlying the Performance Units unless and until the Performance Units vest and certificates representing such Shares (which may be in book-entry form) have been issued and recorded on the Company’s records and delivered to the Participant or to an escrow account for the Participant’s benefit. After such issuance, recordation and delivery, Participant will have the rights of a shareholder of the Company with respect to such Shares, including without limitation, voting rights and the right to receipt of dividends and distributions on such Shares. 11. No Right to Continued Service. Neither the Plan nor this Agreement shall confer upon the Participant any right to serve as an employee or other service provider of the Company or a Subsidiary. Further, nothing in the Plan or this Agreement shall be construed to limit the discretion of the Company or a Subsidiary to terminate the services of the Participant at any time, with or without cause. 12. Adjustments. In the event of a change in capitalization described in Section 13 of the Plan prior to the Vesting Date, other than a dividend described in Section 5 above, the Performance Units shall be equitably adjusted or terminated in any manner contemplated by the Plan to reflect the effect of such event or change in the Company’s capital structure in such a way as to preserve the value of the Award. 13. Required Participant Repayment/Reduction Provision. Notwithstanding anything in the Plan or this Agreement to the contrary, all or a portion of the Award made to the Participant under this Agreement is subject to being called for clawback and repayment to the Company or reduced in any situation required by law or as specified by any and all applicable Company policies, New York Stock Exchange (“NYSE”) rule, or Securities Exchange Commission (“SEC”) rule in effect at the time the clawback and repayment or reduction occurs. In any event, even if not required by law, Company policy, NYSE rule, or SEC rule, in any situation where the Board or a committee thereof determines that fraud, negligence, or intentional misconduct by the Participant was a contributing factor to the Company having to restate all or a portion of its financial statement(s), the Committee may request clawback, repayment, and/or reduction. If the method of clawback, repayment, and/or reduction is not specified by applicable law, Company policies, NYSE rule, or SEC rule, the Committee may determine whether the Company shall effect any such clawback, repayment, and/or reduction: (i) by seeking repayment from the Participant, (ii) by reducing (subject to Applicable Law and the Plan’s terms and conditions or any other applicable plan, program, or arrangement) the amount that would otherwise be awarded or payable to the Participant under the Award, the Plan or any other compensatory plan, program, or arrangement maintained by the Company, (iii) by withholding payment of future increases in compensation (including the payment of any discretionary bonus amount) or grants of compensatory awards that would otherwise have been made in accordance with the Company’s otherwise applicable compensation practices, or (iv) by any combination of the

8 foregoing. The determination regarding the Participant’s conduct, and clawback, repayment, and/or reduction under this provision shall be within the Committee’s sole discretion and shall be final and binding on the Participant and the Company. The Participant, in consideration of the grant of the Award, and by the Participant's execution of this Agreement, acknowledges the Participant's understanding and agreement to this provision, and hereby agrees to make and allow an immediate and complete repayment or reduction in accordance with this provision in the event of a call for clawback, repayment, and/or other action by the Company or Committee to effect its terms with respect to the Participant, the Award and/or any other compensation described herein. 14. Company Policies. The Participant agrees that the Award will be subject to any applicable insider trading policies, retention policies and other policies that may be implemented by the Board, from time to time. 15. Participant Undertaking. The Participant agrees to take whatever additional actions and execute whatever additional documents the Company may in its reasonable judgment deem necessary or advisable in order to carry out or effect one or more of the obligations or restrictions imposed on the Participant pursuant to the terms of this Agreement. It is intended by the Company that the Plan and Shares covered by the Award are to be registered under the Securities Act of 1933, as amended, prior to the grant date; provided that in the event such registration is for any reason not effective for such Shares, the Participant agrees that all Shares acquired pursuant to the grant will be acquired for investment and will not be available for sale or tender to any third party. 16. Beneficiary. The Participant may designate a Beneficiary(ies) (in accordance with the beneficiary designation procedures of the applicable brokerage account where any Shares (or, as applicable, cash) of an Award’s Vested Units will be delivered in accordance with this Agreement upon vesting). Such Beneficiary(ies) will receive any rights of the Participant which may become vested in the event of the Participant’s death. If no Beneficiary is designated under such brokerage account, then upon a Participant’s death, any vested rights of the Participant will be transferred and distributed from the brokerage account in accordance with the procedures of such brokerage account for use in instances in which no beneficiary is designated. 17. Notices. Any notice required to be delivered to the Company under this Agreement shall be in writing and addressed to the Senior Vice President, Chief Human Resource Officer, or his or her successor in charge of compensation and benefits in Human Resources, of the Company at the Company's principal corporate offices. Any notice required to be delivered to the Participant under this Agreement shall be in writing and addressed to the Participant at the Participant's address as shown in the records of the Company. Either party may designate another address in writing (or by such other method approved by the Company) from time to time.

9 18. Incorporation of the Plan; Conflicts. The Performance Units and the Shares issued to Participant hereunder are subject to the terms and conditions set forth in this Agreement and the Plan, which is incorporated herein by reference. In the event of any inconsistency between (1) the Plan and this Agreement, the Plan will control, or (2) the resolutions and records of the Board or Committee and this Agreement, the resolutions and records of the Board or Committee will control. 19. Successors and Assigns. The Company may assign any of its rights under this Agreement, and this Agreement will be binding upon and inure to the benefit of the Company’s successors and assigns. Subject to the restrictions on transfer set forth herein and the Plan, this Agreement will be binding upon and inure to the benefit of the heirs, legatees, legal representatives, successors and assigns of the parties hereto. 20. No Impact on Other Benefits. The Company does not intend for the value of the Award or any Vested Units to be included in the Participant’s normal or expected compensation for purposes of calculating any severance, retirement, welfare, insurance or similar employee benefit; provided, however, that if there is any inconsistency between this Agreement and the terms of another benefit plan, the benefit plan document will control. 21. Discretionary Nature of Plan. The Plan is discretionary and may be amended, cancelled or terminated by the Board at any time, in its discretion. The grant of the Performance Units in this Agreement does not create any contractual right or other right to receive any Performance Units or other awards in the future. Future awards, if any, will be at the Committee’s sole discretion. Any amendment, modification, or termination of the Plan shall not constitute a change or impairment of the terms and conditions of the Participant's employment with the Company. 22. Amendment. In accordance with the Plan, the Committee may amend or otherwise modify, suspend, discontinue or terminate this Agreement at any time, prospectively or retroactively. 23. Section 409A. 23.1 This Award and Agreement is intended to comply with Section 409A or an exemption thereunder and shall be construed and interpreted in a manner that is consistent with the requirements for avoiding additional taxes or penalties under Section 409A. Notwithstanding any other provision of the Agreement, any distributions or payments due hereunder may only be made upon an event and in a manner that complies with Section 409A or an applicable exemption. Any distributions or payments due hereunder upon a termination of employment shall only be made upon a "separation from service" as defined in Section 409A. The right to a series of installment payments under this Agreement shall be treated as a right to a series of

10 separate payments. Except as provided in Section 7, in no event may the Participant, directly or indirectly, designate the calendar year of settlement, distribution or payment. 23.2 If an Award is subject to Section 409A and Participant becomes entitled to settlement of the Award on account of a separation from service and is a “specified employee” within the meaning of Section 409A on the date of the separation from service, then to the extent necessary to prevent any accelerated or additional tax under Section 409A, such settlement will be delayed until the earlier of: (a) the date that is six months following the Participant's separation from service, and (b) the Participant’s death (the “Delayed Payment Date”) and the accumulated amounts shall be distributed or paid in a lump sum payment on the Delayed Payment Date. 23.3 The Company does not represent that the Award or this Agreement complies with Section 409A and in no event shall the Company be liable for all or any portion of any taxes, penalties, interest or other expenses that may be incurred by the Participant on account of non- compliance with Section 409A. 23.4 To the extent that any provision of the Agreement would cause a conflict with the requirements of Section 409A, or would cause the administration of the Agreement to fail to satisfy Section 409A, such provision shall be deemed null and void to the extent permitted by Applicable Law. 24. Entire Agreement. The Plan and this Agreement (including any exhibit hereto) constitute the entire agreement of the parties and supersede in their entirety all prior undertakings and agreements of the Company and the Participant with respect to the subject matter hereof. 25. Severability. The invalidity or unenforceability of any provision of the Plan or this Agreement shall not affect the validity or enforceability of any other provision of the Plan or this Agreement, and each provision of the Plan and this Agreement shall be severable and enforceable to the extent permitted by law. 26. Governing Law. This Agreement will be construed and interpreted in accordance with the laws of the State of Oklahoma without regard to the conflict of laws provisions thereof. 27. Counterparts. This Agreement may be executed in one or more counterparts, including by way of electronic signature, subject to Applicable Law, each of which shall be deemed an original and all of which together will constitute one instrument. 28. Administration of Award; Acceptance. As a condition of receiving this Award, the Participant agrees that the Committee shall have full and final authority to construe and interpret the Plan and this Agreement, and to make all other decisions and determinations as may be required under the Plan or this Agreement as they may deem necessary or advisable for

11 administration of the Plan or this Agreement, and that all such interpretations, decisions and determinations shall be final and binding on the Participant, the Company and all other interested persons. Any dispute regarding the interpretation of this Agreement shall be submitted by the Participant or the Company to the Committee for review. The resolution of such dispute by the Committee shall be final and binding on the Participant and the Company. Day-to-day authority and responsibility has been delegated to the Company’s ONE Gas, Inc. Benefits Committee and its authorized representatives, and all actions taken thereby shall be entitled to the same deference as if taken by the Committee itself. The Participant hereby acknowledges receipt of this Agreement and a copy of the Plan. Participant agrees to be bound by all of the provisions set forth in this Agreement and the Plan and acknowledges that there may be adverse tax consequences upon the vesting or settlement of the Performance Units or disposition of the underlying Shares and that Participant has been advised to consult a tax advisor prior to such vesting, settlement or disposition. Participant accepts the Award under the terms and conditions stated in this Agreement, subject to all terms and provisions of the Plan, by electronic acceptance of the grant.

1 Exhibit A Performance Unit Performance Goal 2024-2026 Performance Period Subject to the terms of the Agreement, Participant shall vest in a percentage of the Target Award (including any Dividend Equivalents) on the Vesting Date, based on the Company’s ranking for Total Stockholder Return (“TSR”) for the Performance Period against the ONE Gas Peer Group listed in Exhibit C, all as determined by the Committee in its sole discretion. TSR for the Performance Period is the measure of the stock price appreciation plus any dividends paid during the Performance Period, expressed as a percentage. The TSR beginning stock price for the Performance Period is the average of the closing stock price for the 20 trading days immediately preceding the beginning of the Performance Period. The TSR ending stock price for the Performance Period is the average of the closing stock price for the 20 trading days leading up to and including the last day of the Performance Period. Exhibit B provides an illustration of a Hypothetical Performance Period calculation. The number of Performance Units earned at the time of vesting is based on the Company’s TSR percentile rank for the Performance Period as set forth in the following chart. If the actual TSR percentile rank falls between the stated percentile ranks set forth in the chart, the payout percentage is interpolated between the percentile rank above and below the actual percentile rank, except that no Performance Units are earned if ONE Gas’s TSR ranking at the end of the Performance Period is below the 25th percentile. Percentile Rank Payout (as a % of Target) 90th percentile and above 200% 75th percentile 150% 50th percentile 100% 25th percentile 50% Below the 25th percentile 0%

2 Exhibit B Illustration of Hypothetical 2024-2026 Performance Period Performance Unit Award Calculation Illustration assumes 500 Performance Units Granted in February 2024 Total Stockholder Return (“TSR”) vs. ONE Gas Peer Group Hypothetical ONE Gas TSR Ranking = 40th percentile A 40th percentile TSR ranking earns 80% of Performance Units granted (i.e., 500 units) as interpolated between 50% and 100% from Exhibit A (see chart above) 400 Performance Units earned* Total Performance Units Earned 400 Performance Units 400* Performance Units earned out of 500 units granted = 80% “earn-out” [80% of 500 shares paid and distributed in the form of Shares] *In addition, applicable Dividend Equivalents will be added with an 80% “earn-out.”

3 Exhibit C 2024-2026 ONE GAS TSR Peer Group Company Name Sym Alliant Energy Corporation LNT Atmos Energy Corporation ATO Avista Corporation AVA Black Hills Corporation BKH CenterPoint Energy, Inc. CNP Chesapeake Utilities Corporation CPK CMS Energy Corporation CMS New Jersey Resources Corporation NJR NiSource Inc. NI Northwest Natural Holding Company NWN NorthWestern Energy Group, Inc. NWE Southwest Gas Holdings, Inc. SWX Spire Inc. SR In the event that any of the Peer Group companies are not available for performance comparison either by going out of business, being sold, being merged into another company or any other reason, then that company will be dropped from the list and the performance comparison will be made with the remaining Peer Group companies.

4 Exhibit D ONE Gas, Inc. Amended and Restated Equity Compensation Plan (2018) Performance Unit Deferral Election INSTRUCTIONS: This Deferral Election must be completed and returned to the plan administrator at ONE Gas, Inc. no later than June 30, 2026 (the “Election Deadline”). This election becomes irrevocable as of the Election Deadline; provided, however, this election shall only become effective to the extent permitted by Section 409A. This Election is made by the undersigned Participant pursuant to the terms of the ONE Gas, Inc. Amended and Restated Equity Compensation Plan (2018), as amended from time to time (the “Plan”) and that certain Performance Unit Award Agreement issued to me under the Plan on #GrantDate# (the “Agreement”). Capitalized terms that are used but not defined herein have the meanings set forth in the Agreement. 1. Irrevocable Elections as to the Time and Form of Payment I hereby irrevocably elect to defer the payment and my receipt of all Performance Units, Shares and cash that I may become entitled to receive pursuant to the Agreement (the “Deferred Amounts”) from the regularly scheduled time of payment set forth in Section 6 of the Agreement until a later date as follows: A. Specified Time of Payment Election (Put initials by your choice) ___ I elect to have the Deferred Amounts deferred and paid to me on the later of: (i) the date of my separation from service as an employee of the Company, or (ii) [________, 20__] in the form specified below. ___ I elect to have the Deferred Amounts deferred and paid to me on the date of my separation from service as an employee of the Company in the form specified below. B. Form of Payment Election (Put initials by your choice) ___ I elect to receive the Deferred Amounts in a single lump sum payment. ____ I elect to receive the Deferred Amounts in ______ (specify 2, 3, 4 or 5) equal annual installments commencing on the Specified Time of Payment that I have elected in Part A above, until fully paid. The number of Shares or cash received in each installment will equal the number and amount, respectively, that have not been paid as of the date immediately preceding the installment payment date, divided by the number of installments remaining to be paid as of the date immediately preceding the installment payment date. The resulting number shall

5 be rounded down to the next whole number, except that the final installment shall be rounded up to the next whole number. C. Election in the Event of Death (Put initials by your choice) ___ In the event of my death prior to, or after, the Specified Time of Payment that I have elected above, I elect to have my Deferred Amounts paid and distributed in a single sum within 60 days of my death to the brokerage account where any Shares (or, as applicable, cash) of an Award’s Vested Units would otherwise have transferred upon vesting, to be further paid and distributed in accordance with the beneficiary procedures of such brokerage account to my brokerage account named Beneficiary(ies), or in the case of no Beneficiary designation under the procedures established by such brokerage account for use in instances when there is no such Beneficiary designation. ___ In the event of my death prior to, or after, the Specified Time of Payment that I have elected above, I elect to have my Deferred Amounts paid and distributed to the brokerage account where any Shares (or, as applicable, cash) of an Award’s Vested Units would otherwise have transferred upon vesting in ______ (specify 2, 3, 4 or 5) equal annual installments commencing within 60 days following my death, until fully paid, to be further paid and distributed in accordance with the beneficiary procedures of such brokerage account to my brokerage account named Beneficiary(ies), or in the case of no beneficiary designation under the procedures established by such brokerage account for use in instances when there is no such Beneficiary designation. The number of Shares or cash received in each installment will equal the number and amount, respectively, that have not been paid as of the date immediately preceding the installment payment date, divided by the number of installments remaining to be paid as of the same date. The resulting number shall be rounded down to the next whole number, except that the final installment shall be rounded up to the next whole number. D. Change in Ownership or Control (Mandatory Distribution) Notwithstanding the above elections, if a Change in Ownership or Control (within the meaning of Section 409A) occurs prior to the full distribution of the Deferred Amounts, all Deferred Amounts that have not been paid and transferred will be paid and transferred on the date of the Change in Ownership or Control. In the event Shares no longer exist at the time of payment and transfer, each of the deferred Performance Units shall be converted in a manner that is consistent with the manner in which Shares held by shareholders of the Company were treated with respect to the Change in Ownership or Control.

6 2. Additional Terms A. Unforeseeable Emergency. You may request an accelerated payment of all or a portion of the Deferred Amounts if you experience an Unforeseeable Emergency (as defined in the Plan), subject to the requirements set forth in Plan Section 11.5. If approved, payment shall be made in a single lump sum within 90 days after the approval date. B. Specified Employee. If you become entitled to a distribution on account of a separation from service and you are “specified employee” (within the meaning of Section 409A) on the date of your separation from service, payment of all or a portion of your Deferred Amounts may be delayed in accordance with Plan Section 11.4. C. Re-deferrals and Changing the Form of Payment. You may, at the Committee’s discretion, be permitted to make a re-deferral election with respect to the amounts deferred hereunder in accordance with Plan Section 11.3. D. Withholding. You will be required to satisfy any tax withholding obligations relating to the Deferred Amounts, and delivery of the Shares or cash will be conditional upon your satisfaction of such obligations. 3. Acknowledgment By executing this Election, I acknowledge that: A. I have read the terms of the Plan, the Agreement and this Election and agree to all the terms and conditions. B. I understand that any amounts that I defer hereunder are unfunded and unsecured and subject to the claims of the Company’s creditors in the event of the Company’s insolvency. C. I understand that the Plan, the Agreement and this Election are intended to comply with Section 409A and that they will be interpreted accordingly. However, I understand that the Company will have no liability with respect to any failure to comply with Section 409A. D. I understand that this Election will become irrevocable as of the Election Deadline. E. I have consulted with my own legal, tax, and financial advisors regarding the legal, financial, and tax consequences of participating in the Plan and making this election. I hereby make this election as of this ___ day of ____, 20__. _____________________________________ Participant Signature _____________________________________ Print Participant’s Name

7 _____________________________________ Employee ID Number Copy received this ____ day of ________, 20__, ______________________________________ For the Committee


Oklahoma		46-3561936
(State or other jurisdiction of incorporation or organization)		(I.R.S. Employer Identification No.)

15 East Fifth Street
Tulsa,	OK	74103
(Address of principal executive offices)		(Zip Code)


Part I.
Item 1.	Business	7
Item 1A.	Risk Factors	13
Item 1B.	Unresolved Staff Comments	17
Item 1 C .	Cybersecurity	17
Item 2.	Properties	19
Item 3.	Legal Proceedings	19
Item 4.	Mine Safety Disclosures	19
Part II.
Item 5.	Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities	20
Item 6.	[Reserved]	21
Item 7.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	21
Item 7A.	Quantitative and Qualitative Disclosures about Market Risk	37
Item 8.	Financial Statements and Supplementary Data	39
Item 9.	Changes in and Disagreements with Accountants on Accounting and Financial Disclosure	77
Item 9A.	Controls and Procedures	77
Item 9B.	Other Information	77
Item 9C.	Disclosure Regarding Foreign Jurisdictions that Prevent Inspections	77
Part III.
Item 10.	Directors, Executive Officers and Corporate Governance	77
Item 11.	Executive Compensation	78
Item 12.	Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters	78
Item 13.	Certain Relationships and Related Transactions, and Director Independence	79
Item 14.	Principal Accountant Fees and Services	79
Part IV.
Item 15.	Exhibits, Financial Statement Schedules	80
Item 16.	Form 10-K Summary	85
Signatures		86


The abbreviations, acronyms and industry terminology used in this Annual Report are defined as follows:

AAO			Accounting Authority Order
ADIT			Accumulated deferred income taxes
AFUDC			Allowance for funds used during construction
Annual Report			Annual Report on Form 10-K for the year ended December 31, 2023
ASC			Accounting Standards Codification
ASU			Accounting Standards Update
Bcf			Billion cubic feet
CAA			Federal Clean Air Act, as amended
CERCLA			Federal Comprehensive Environmental Response, Compensation and Liability Act of 1980, as amended
CFTC			Commodities Futures Trading Commission
CISA			Cybersecurity and Infrastructure Security Agency
Clean Water Act			Federal Water Pollution Control Amendments of 1972, as amended
CNG			Compressed natural gas
Code			Internal Revenue Code of 1986, as amended
COSA			Cost-of-Service Adjustment
DART			Days Away, Restricted or Transferred Incident Rate; calculated by multiplying the total number of recordable injuries and illnesses, or one or more restricted days that resulted in an employee transferring to a different job within the company by 200,000, and then dividing that number by the total number of hours worked by all employees
DHS			United States Department of Homeland Security
DOT			United States Department of Transportation
Dth			Dekatherm
ECP			The ONE Gas, Inc. Amended and Restated Equity Compensation Plan (2018)
EDIT			Excess deferred income taxes resulting from a change in enacted tax rates
EPA			United States Environmental Protection Agency
EPS			Earnings per share
ER			Emissions Reduction; measured by the reduction of MTCO2e emissions through planned vintage main replacements and service line replacements.
ERT			Emergency Response Time; calculated as the time between the creation of an emergency order and the arrival of a first company responder to the scene expressed as the percentage of emergency orders with a response time of 30 minutes or less
ESG			Environmental, social and governance
ESPP			The ONE Gas, Inc. Amended and Restated Employee Stock Purchase Plan
Exchange Act			Securities Exchange Act of 1934, as amended
FASB			Financial Accounting Standards Board
FERC			Federal Energy Regulatory Commission
GAAP			Accounting principles generally accepted in the United States of America
GRIP			Gas Reliability Infrastructure Program
GSRS			Gas System Reliability Surcharge

HDD			Heating degree day is a measure designed to reflect the demand for energy needed for heating based on the extent to which the daily average temperature falls below a reference temperature for which no heating is required, usually 65 degrees Fahrenheit
IRS			United States Internal Revenue Service
IT			Information Technology
KCC			Kansas Corporation Commission
KDHE			Kansas Department of Health and Environment
KGSS-I			Kansas Gas Service Securitization I, L.L.C.
LDC			Local distribution company
LIBOR			London Interbank Offered Rate

MGP			Manufactured gas plant
MMcf			Million cubic feet
Moody’s			Moody’s Investors Service, Inc.


MTCO2e			Metric ton of carbon dioxide equivalent
NPRM			Notice of proposed rulemaking
NYSE			New York Stock Exchange
OCC			Oklahoma Corporation Commission
ODFA			Oklahoma Development Finance Authority
ONE Gas			ONE Gas, Inc.
ONE Gas Credit Agreement			ONE Gas’ $1.2 billion revolving credit agreement, as amended
OSHA			Occupational Safety and Health Administration
PBRC			Performance-Based Rate Change
PHMSA			United States Department of Transportation Pipeline and Hazardous Materials Safety Administration

PIPES Act			Protecting Our Infrastructure of Pipelines and Enhancing Safety (PIPES) Act of 2020
PVIR			Preventable Vehicle Incident Rate; calculated by multiplying the number of total preventable vehicle incidents by 1,000,000 and then dividing that number by the total number of business use miles driven
Quarterly Report(s)			Quarterly Report(s) on Form 10-Q
RNG			Renewable natural gas
ROE			Return on equity calculated consistent with utility ratemaking principles in each jurisdiction in which we operate
RRC			Railroad Commission of Texas
S&P			Standard & Poor’s Ratings Services
SEC			Securities and Exchange Commission
Securities Act			Securities Act of 1933, as amended
Securitized Utility Tariff Bonds			Series 2022-A Senior Secured Securitized Utility Tariff Bonds, Tranche A
Securitized Utility Tariff Property			Securitized Utility Tariff Property as defined in the financing order issued by the KCC in August 2022
Senior Notes			ONE Gas’ registered unsecured notes consisting of $300 million of 3.61 percent senior notes due February 2024, $473 million of 1.10 percent senior notes due March 2024, $300 million of 5.10 percent senior notes due April 2029, $300 million of 2.00 percent senior notes due May 2030, $300 million of 4.25 percent senior notes due September 2032, $600 million of 4.66 percent senior notes due February 2044 and $400 million of 4.50 percent senior notes due November 2048
SOFR			Secured Overnight Financing Rate administered by the Federal Reserve Bank of New York
TCEQ			Texas Commission on Environmental Quality
TNG Corporation			Texas Natural Gas Securitization Finance Corporation
TPFA			Texas Public Finance Authority
TRIR			Total Recordable Incident Rate; calculated by multiplying the number of recordable cases by 200,000, and then dividing that number by the number of hours worked by all employees
TSA			United States Department of Homeland Security’s Transportation Security Administration
WNA			Weather normalization adjustment(s)
XBRL			eXtensible Business Reporting Language


Division	Jurisdiction	Effective Date of Last Action(1)	Rate Base (millions)	Pre-Tax Rate of Return	Equity Ratio	ROE
Oklahoma Natural Gas (2)	Oklahoma	June 2023	$2,066	8.95%	59%	9.40%
Kansas Gas Service (3)	Kansas	November 2023	$1,330	8.60%	N/A	9.30%
Texas Gas Service (2)	Central-Gulf	June 2023	$617	8.95%	59%	9.50%
	West-North	June 2023	$589	8.91%	60%	9.60%
	Rio Grande Valley	January 2024	$160	8.95%	59%	9.70%


(1)			Effective date of last approved rate case or interim filing.
(2)			The rate base, authorized ROE, authorized debt/equity ratio and authorized return on equity presented in this table are those from the most recent approved regulatory filing for Oklahoma Natural Gas and Texas Gas Service.
(3)			Kansas Gas Service’s most recent rate case, approved in February 2019, settled without a determination of rate base, ROE, authorized debt/equity ratio and authorized return on equity. This reflects Kansas Gas Service’s estimate of rate base from that rate case adjusted for approved GSRS filings and ROE embedded in the pre-tax carrying charge utilized in its GSRS filing.
(4)			Our purchased gas adjustment mechanisms allow recovery of expenses the Company incurs to purchase, transport, and store natural gas for our customers. These costs are passed on to customers without markup.
(5)			We recover the gas cost portion of bad debts through our various purchased gas adjustment mechanisms.
(6)			Expense trackers include pension and other postemployment benefits costs for Kansas Gas Service and Texas Gas Service, ad-valorem taxes in Kansas and pipeline integrity testing expenses in Texas.


	Years Ended December 31,
Operational measure	2023	2022	2021
ER	3,076	—	—
TRIR	—	1.37	0.96
DART	0.16	0.22	0.22
PVIR	1.82	1.84	2.10
ERT	64.8%	62.7%	62.7%


Properties (miles)	OK	KS	TX	Total
Distribution	19,600	11,800	11,100	42,500
Transmission	500	1,500	300	2,300
Total properties	20,100	13,300	11,400	44,800


	Cumulative Total Return As of Each Year Ended
	Cumulative Total Return As of Each Year Ended
	December 31,
	2019		2020		2021		2022		2023
ONE Gas, Inc.	$	120.28	$	101.36	$	105.78	$	106.40	$	92.79
S&P MidCap 400 Utilities Index	$	114.33	$	98.47	$	117.92	$	117.74	$	102.19
S&P MidCap 400 Index	$	126.17	$	143.39	$	178.85	$	155.42	$	180.90
Dow Jones Industrial Average	$	125.34	$	137.53	$	166.34	$	154.92	$	180.00
ONE Gas Peer Group*	$	118.15	$	104.83	$	123.73	$	127.65	$	123.31
* The ONE Gas peer group used in this graph is the same peer group that will be used in determining our level of performance under our 2023 performance units at the end of the three-year performance period and is comprised of the following companies: Alliant Energy Corporation; Atmos Energy Corporation; Avista Corporation; Black Hills Corporation; CenterPoint Energy, Inc.; Chesapeake Utilities Corporation; CMS Energy Corporation; New Jersey Resources Corporation; NiSource Inc.; Northwest Natural Holding Company; NorthWestern Energy Group, Inc.; Southwest Gas Holdings, Inc.; and Spire Inc.


		Years Ended						Variances				Variances
		December 31,						2023 vs. 2022				2022 vs. 2021
Financial Results		2023		2022		2021		Increase (Decrease)				Increase (Decrease)
	(Millions of dollars, except percentages)
Natural gas sales		$	2,154.0	$	2,412.9	$	1,661.7	$	(258.9)	(11)	%	$	751.2	45	%
Transportation revenues		133.6		126.5		119.0		7.1		6	%	7.5		6	%
Securitization customer charges		48.7		5.8		—		42.9		740	%	5.8		100	%
Other revenues		35.7		32.8		27.9		2.9		9	%	4.9		18	%
Total revenues		2,372.0		2,578.0		1,808.6		(206.0)		(8)	%	769.4		43	%
Cost of natural gas		1,134.5		1,459.1		775.0		(324.6)		(22)	%	684.1		88	%
Operating costs		580.1		540.4		516.1		39.7		7	%	24.3		5	%
Depreciation and amortization		279.8		228.5		207.2		51.3		22	%	21.3		10	%
Operating income		$	377.6	$	350.0	$	310.3	$	27.6	8	%	$	39.7	13	%
Net Income		$	231.2	221.7		206.4		$	9.5	4	%	$	15.3	7	%
Capital expenditures and asset removal costs		$	728.7	$	656.5	$	544.3	$	72.2	11	%	$	112.2	21	%


	Years Ended December 31,

Volumes (MMcf)		2023	2022	2021
Natural gas sales
Residential		114,239	125,286	117,758
Commercial and industrial		40,630	43,184	37,615
Other		1,737	2,725	2,521
Total sales volumes delivered		156,606	171,195	157,894
Transportation		227,875	230,080	229,935
Total volumes delivered		384,481	401,275	387,829


Maturity	Original Shares	Remaining Shares	Net Proceeds Available (in thousands)		Forward Price
December 31, 2024	926,465	926,465	$	74,396	$	80.30
December 31, 2024	2,000,000	1,257,000	96,709		76.94
December 31, 2024	1,200,000	1,200,000	88,823		74.02
December 31, 2024	180,000	180,000	13,315		73.97
Total forward sale agreements	4,306,465	3,563,465	$	273,243	$	76.68



	Year Ended December 31,					Variance		Variance
		2023		2022		2021			2023 vs. 2022		2022 vs. 2021
		(Millions of dollars)
Total cash provided by (used in):
Operating activities		$	939.5	$	1,570.8	$	(1,535.7)		$	(631.3)	$	3,106.5
Investing activities		(669.6)		(614.1)		(501.1)			(55.5)		(113.0)
Financing activities		(248.6)		(947.4)		2,037.6			698.8		(2,985.0)
Change in cash, cash equivalents, restricted cash and restricted cash equivalents		21.3		9.3		0.8			12.0		8.5
Cash, cash equivalents, restricted cash and restricted cash equivalents at beginning of period		18.1		8.8		8.0			9.3		0.8
Cash, cash equivalents, restricted cash and restricted cash equivalents at end of period		$	39.4	$	18.1	$	8.8		$	21.3	$	9.3


	Rate Used		Cost Sensitivity (a)		Obligation Sensitivity (b)
			(Millions of dollars)
Discount rate for pension	5.30	%	$	2.3	$	21.3
Discount rate for other postemployment benefits	5.40	%	(0.2)		3.4
Expected long-term return on plan assets for pension	6.70	%	2.2		—
Expected long-term return on plan assets for other postemployment benefits	5.20	%	0.4		—


ONE Gas, Inc.
CONSOLIDATED STATEMENTS OF INCOME

	Years Ended December 31,
		2023		2022		2021
		(Thousands of dollars, except per share amounts)

Total revenues		$	2,371,990	$	2,578,005	$	1,808,597

Cost of natural gas		1,134,510		1,459,087		775,006

Operating expenses
Operations and maintenance		508,399		472,265		449,676
Depreciation and amortization		279,830		228,479		207,233
General taxes		71,661		68,217		66,424
Total operating expenses		859,890		768,961		723,333
Operating income		377,590		349,957		310,258
Other income (expense), net		9,476		(4,183)		(3,207)
Interest expense, net		(115,339)		(77,506)		(60,301)
Income before income taxes		271,727		268,268		246,750
Income taxes		(40,495)		(46,526)		(40,316)
Net income		$	231,232	$	221,742	$	206,434

Earnings per share
Basic		$	4.16	$	4.09	$	3.85
Diluted		$	4.14	$	4.08	$	3.85

Average shares (thousands)
Basic		55,600		54,207		53,575
Diluted		55,860		54,338		53,674

Dividends declared per share of stock		$	2.60	$	2.48	$	2.32











	Years Ended December 31,
	2023		2022		2023 vs. 2022		2023		2022
HDDs	Actual	Normal	Actual	Normal	Actual Variance		Actual as a percent of Normal
Oklahoma	3,125	3,346	3,621	3,346	(14)	%	93	%	108	%
Kansas	4,117	4,721	4,779	4,722	(14)	%	87	%	101	%
Texas	1,558	1,705	1,950	1,764	(20)	%	91	%	111	%


Rating Agency	Rating	Outlook
Moody’s	A3	Stable
S&P	A-	Stable


ONE Gas, Inc.
CONSOLIDATED BALANCE SHEETS
(Continued)
	December 31,		December 31,
	2023		2022
Equity and Liabilities	(Thousands of dollars)
Equity and long-term debt
Common stock, $0.01 par value: authorized 250,000,000 shares; issued and outstanding 56,545,924 shares at December 31, 2023; issued and outstanding 55,349,954 shares at December 31, 2022	$	565	$	553
Paid-in capital	2,028,755		1,932,714
Retained earnings	737,739		651,863
Accumulated other comprehensive loss	(1,182)		(704)

Total equity	2,765,877		2,584,426
Other long-term debt, excluding current maturities, net of issuance costs	1,877,895		2,352,400
Securitized utility tariff bonds, excluding current maturities, net of issuance costs	282,506		309,343
Total long-term debt, excluding current maturities, net of issuance costs	2,160,401		2,661,743
Total equity and long-term debt	4,926,278		5,246,169
Current liabilities
Current maturities of other long-term debt	772,984		12
Current maturities of securitized utility tariff bonds	27,430		20,716
Notes payable	88,500		552,000
Accounts payable	278,056		360,493

Accrued taxes other than income	68,793		78,352

Regulatory liabilities	66,901		47,867
Customer deposits	62,187		57,854
Other current liabilities	112,370		72,125
Total current liabilities	1,477,221		1,189,419
Deferred credits and other liabilities
Deferred income taxes	752,068		698,456
Regulatory liabilities	500,478		529,441
Employee benefit obligations	20,265		19,587
Other deferred credits	94,684		93,324
Total deferred credits and other liabilities	1,367,495		1,340,808
Commitments and contingencies
Total liabilities and equity	$	7,770,994	$	7,776,396


ONE Gas, Inc.
CONSOLIDATED STATEMENTS OF CASH FLOWS
	Year Ended December 31,

	2023		2022		2021
	(Thousands of dollars)
Operating activities
Net income	$	231,232	$	221,742	$	206,434
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	279,830		228,479		207,233
Deferred income taxes	24,773		(22,034)		43,449
Share-based compensation expense	12,184		10,741		10,498
Provision for doubtful accounts	9,698		6,003		9,131
Proceeds from government securitization of winter weather event costs	197,366		1,330,582		—
Changes in assets and liabilities:
Accounts receivable	196,272		(213,656)		(57,902)
Materials and supplies	(6,776)		(15,981)		(2,126)
Natural gas in storage	82,108		(89,559)		(85,700)

Asset removal costs	(62,023)		(47,032)		(49,029)
Accounts payable	(90,046)		85,915		107,207

Accrued taxes other than income	(9,559)		11,317		3,235

Customer deposits	4,333		(4,600)		(5,574)
Regulatory assets and liabilities - current	7,249		52,417		(1,562,574)
Regulatory assets and liabilities - noncurrent	38,869		53,992		(367,210)

Other assets and liabilities - current	26,070		(23,377)		18,461
Other assets and liabilities - noncurrent	(2,048)		(14,107)		(11,190)
Cash provided by (used in) operating activities	939,532		1,570,842		(1,535,657)
Investing activities
Capital expenditures	(666,634)		(609,486)		(495,246)
Other investing expenditures	(8,508)		(8,632)		(7,554)
Other investing receipts	5,499		4,008		1,717
Cash used in investing activities	(669,643)		(614,110)		(501,083)
Financing activities
Borrowings (repayments) of notes payable, net	(463,500)		58,000		75,775
Issuance of other long-term debt, net of discounts	299,583		297,591		2,498,895


ONE Gas, Inc.
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME

	Years Ended December 31,

			2023		2022		2021
		(Thousands of dollars)
Net income			$	231,232	$	221,742	$	206,434
Other comprehensive income, net of tax
Change in pension and other postemployment benefit plan liability, net of tax of $140, $(1,705), and $(379), respectively			(478)		5,823		1,250
Total other comprehensive income (loss), net of tax			(478)		5,823		1,250
Comprehensive income			$	230,754	$	227,565	$	207,684


ONE Gas, Inc.
CONSOLIDATED STATEMENTS OF EQUITY

	Common Stock Issued	Common Stock		Paid-in Capital		Retained Earnings		Accumulated Other Comprehensive Income/(Loss)		Total Equity
	(Shares)	(Thousands of dollars)

January 1, 2021	53,166,733	$	532	$	1,756,921	$	483,635	$	(7,777)	$	2,233,311
Net income	—	—		—		206,434		—		206,434
Other comprehensive income	—	—		—		—		1,250		1,250
Common stock issued and other	466,477	4		32,445		—		—		32,449
Common stock dividends - $2.32 per share	—	—		996		(124,908)		—		(123,912)
December 31, 2021	53,633,210	536		1,790,362		565,161		(6,527)		2,349,532
Net income	—	—		—		221,742		—		221,742
Other comprehensive income	—	—		—		—		5,823		5,823
Common stock issued and other	1,716,744	17		141,266		—		—		141,283
Common stock dividends - $2.48 per share	—	—		1,086		(135,040)		—		(133,954)
December 31, 2022	55,349,954	553		1,932,714		651,863		(704)		2,584,426
Net income	—	—		—		231,232		—		231,232
Other comprehensive income	—	—		—		—		(478)		(478)
Common stock issued and other	1,195,970	12		94,779		—		—		94,791
Common stock dividends - $2.60 per share	—	—		1,262		(145,356)		—		(144,094)
December 31, 2023	56,545,924	$	565	$	2,028,755	$	737,739	$	(1,182)	$	2,765,877


		December 31, 2023
	Remaining Recovery Period	Current		Noncurrent		Total
		(Thousands of dollars)
Winter weather event costs	(a)	$	22,633	$	21,495	$	44,128
Under-recovered purchased-gas costs	1 year	10,391		—		10,391
Pension and postemployment benefit costs	See Note 11	6,379		228,092		234,471
Reacquired debt costs	6 years	723		2,712		3,435
MGP remediation costs	15 years	98		31,893		31,991
Ad-valorem tax	1 year	14,533		—		14,533
WNA	1 year	11,404		—		11,404
Customer credit deferrals	1 year	6,184		—		6,184
Other	1 to 18 years	2,963		3,714		6,677
Total regulatory assets, net of amortization		75,308		287,906		363,214
Income tax rate changes	(a)	—		(500,478)		(500,478)
Over-recovered purchased-gas costs	1 year	(66,901)		—		(66,901)
Total regulatory liabilities		(66,901)		(500,478)		(567,379)
Net regulatory assets and liabilities		$	8,407	$	(212,572)	$	(204,165)
(a) Recovery period varies by jurisdiction. See discussion below for additional information regarding our regulatory assets related to winter weather event costs and regulatory liabilities related to federal income tax rate changes.


	Interest rate at December 31, 2023	December 31, 2023		December 31, 2022
		(Thousands of dollars)
Senior Notes due:
February 2024	3.610%	$	300,000	$	300,000
March 2024	1.100%	473,000		473,000
April 2029	5.100%	300,000		—
May 2030	2.000%	300,000		300,000
September 2032	4.250%	300,000		300,000
February 2044	4.658%	600,000		600,000
November 2048	4.500%	400,000		400,000
Total Senior Notes		2,673,000		2,373,000
KGSS-I Securitized Utility Tariff Bonds	5.486%	315,284		336,000
Other	8.000%	1,238		1,250
Unamortized discounts on long-term debt		(7,615)		(7,636)
Debt issuance costs (a)		(21,092)		(20,143)
Total long-term debt, net		2,960,815		2,682,471
Less: current maturities of securitized utility tariff bonds, net		27,430		20,716
Less: current maturities of other long-term debt, net		772,984		12
Noncurrent portion of long-term debt, net		$	2,160,401	$	2,661,743


	Year Ended
	December 31,
Other information related to operating leases	2023			2022			2021
	(Millions of dollars)
Weighted-average remaining lease term	4 years			5 years			6 years
Weighted-average discount rate	4.28		%	4.04		%	2.78		%
Supplemental cash flows information
Lease payments	$	(8.3)		$	(8.2)		$	(8.0)
Right-of-use assets obtained in exchange for lease obligations	$	3.9		$	0.3		$	0.4



	December 31,
Future minimum lease payments under non-cancellable operating leases	2023
	(Millions of dollars)
2024	$	6.7
2025	4.9
2026	3.3
2027	3.1
2028	2.8
Thereafter	1.4
Total future minimum lease payments	$	22.2
Imputed interest	(1.9)
Total operating lease liability	$	20.3

Consolidated balance sheets as of December 31, 2023
Current operating lease liability	$	6.0
Long-term operating lease liability	14.3
Total operating lease liability	$	20.3


	Accumulated Other Comprehensive Income (Loss)
	(Thousands of dollars)
January 1, 2022	$	(6,527)
Pension and other postemployment benefit plans obligations
Other comprehensive income before reclassification, net of tax of $(1,669)	5,701
Amounts reclassified from accumulated other comprehensive income (loss), net of tax of $(36)	122
Other comprehensive income	5,823
December 31, 2022	(704)
Pension and other postemployment benefit plans obligations
Other comprehensive loss before reclassification, net of tax of $140	(479)
Amounts reclassified from accumulated other comprehensive income, net of tax of $—	1
Other comprehensive loss	(478)
December 31, 2023	$	(1,182)


	Years Ended							Affected Line Item in the
Details About Accumulated Other	December 31,							Consolidated Statements
Comprehensive Loss Components		2023		2022		2021			of Income
		(Thousands of dollars)
Pension and other postemployment benefit plan obligations (a)
Amortization of net loss		$	1,960	$	17,010	$	45,896
Amortization of unrecognized prior service cost		525		289		(279)
		2,485		17,299		45,617
Regulatory adjustments (b)		(2,484)		(17,141)		(44,055)
		1		158		1,562			Income before income taxes
		—		(36)		(390)			Income tax expense
Total reclassifications for the period		$	1	$	122	$	1,172		Net income




















	Year Ended December, 31, 2023
	Income		Shares	Per Share Amount
	(Thousands, except per share amounts)
Basic EPS Calculation
Net income available for common stock	$	231,232	55,600	$	4.16
Diluted EPS Calculation
Effect of dilutive securities	—		260
Net income available for common stock and common stock equivalents	$	231,232	55,860	$	4.14

	Year Ended December, 31, 2022
	Income		Shares	Per Share Amount
	(Thousands, except per share amounts)
Basic EPS Calculation
Net income available for common stock	$	221,742	54,207	$	4.09
Diluted EPS Calculation
Effect of dilutive securities	—		131
Net income available for common stock and common stock equivalents	$	221,742	54,338	$	4.08

	Year Ended December, 31, 2021
	Income		Shares	Per Share Amount
	(Thousands, except per share amounts)
Basic EPS Calculation
Net income available for common stock	$	206,434	53,575	$	3.85
Diluted EPS Calculation
Effect of dilutive securities	—		99
Net income available for common stock and common stock equivalents	$	206,434	53,674	$	3.85


	Number of Units	Weighted- Average Grant Date Fair Value
Nonvested at December 31, 2022	116,633	$	79.32
Granted	48,841	$	81.79
Vested	(31,328)	$	90.94
Forfeited	(7,198)	$	77.65
Nonvested at December 31, 2023	126,948	$	77.50


	Pension Benefits				Other Postemployment Benefits
	December 31,				December 31,
	2023		2022		2023		2022
Changes in Benefit Obligation	(Thousands of dollars)
Benefit obligation, beginning of period	$	784,633	$	1,049,990	$	168,342	$	222,806
Service cost	7,242		10,369		730		1,274
Interest cost	42,428		36,150		9,154		6,448
Plan participants’ contributions	—		—		2,823		3,035
Actuarial loss (gain)	23,015		(259,261)		(5,551)		(48,609)
Benefits paid	(53,713)		(55,326)		(16,963)		(16,612)

Plan amendments	—		2,711		—		—

Benefit obligation, end of period	$	803,605	$	784,633	158,535		$	168,342

Change in Plan Assets
Fair value of plan assets, beginning of period	$	768,961	$	1,013,244	$	181,877	$	231,994
Actual return (loss) on plan assets	78,827		(190,484)		11,325		(38,432)
Employer contributions	1,306		1,527		2,546		1,892
Plan participants’ contributions	—		—		2,823		3,035
Benefits paid	(53,713)		(55,326)		(16,963)		(16,612)

Fair value of assets, end of period	795,381		768,961		181,608		181,877
Benefit Asset (Obligation), net at December 31	$	(8,224)	$	(15,672)	$	23,073	$	13,535

Other noncurrent assets	$	13,409	$	5,267	$	23,073	$	13,535
Current liabilities	(1,368)		(1,352)		—		—
Noncurrent liabilities	(20,265)		(19,587)		—		—
Benefit Asset (Obligation), net at December 31	$	(8,224)	$	(15,672)	$	23,073	$	13,535


	2023	2022
Health care cost-trend rate assumed for next year	6.00%	6.50%
Rate to which the cost-trend rate is assumed to decline (the ultimate trend rate)	4.50%	4.50%
Year that the rate reaches the ultimate trend rate	2030	2030


Investment-grade bonds	70.0	%
U.S. large-cap equities	13.0	%
Alternative investments	7.0	%
Developed foreign large-cap equities	5.0	%
Mid-cap equities	3.0	%
Emerging markets equities	1.0	%
Small-cap equities	1.0	%
Total	100.0	%


	Pension Benefits
	December 31, 2023
Asset Category	Level 1		Level 2		Level 3		Total
	(Thousands of dollars)
Investments:
Equity securities (a)	$	88,477	$	—	$	—	$	88,477
Government obligations	—		204,669		—		204,669
Corporate obligations (b)	—		366,482		—		366,482
Cash and money market funds (c)	5,300		28,977		—		34,277
Insurance contracts and group annuity contracts	—		—		12,350		12,350
Other investments (d)	—		—		89,126		89,126
Total assets	$	93,777	$	600,128	$	101,476	$	795,381


	December 31, 2023
	Fair Value		Unfunded Commitments		Redemption Frequency	Redemption Notice Period
	(in thousands)					(in days)
Grosvenor Registered Multi Limited Partnership	$	40,872	$	—	quarterly	65
K2 Institutional Investors II Limited Partnership	$	48,254	$	—	quarterly	91


	Pension Benefits
	Insurance Contracts		Other Investments		Total
	(Thousands of dollars)
January 1, 2022	$	17,301	$	91,456	$	108,757
Unrealized gains	1,467		—		1,467
Unrealized losses	—		(7,458)		(7,458)
Purchases	182		3,033		3,215
Settlements	(4,470)		—		(4,470)
December 31, 2022	$	14,480	$	87,031	$	101,511
Unrealized gains	—		2,095		2,095
Unrealized losses	(618)		—		(618)
Purchases	1,562		—		1,562
Settlements	(3,074)		—		(3,074)
December 31, 2023	$	12,350	$	89,126	$	101,476


	Pension Benefits		Other Postemployment Benefits
Benefits to be paid in:	(Thousands of dollars)
2024	$	55,391	$	14,127
2025	$	55,988	$	13,890
2026	$	56,422	$	13,505
2027	$	56,591	$	13,194
2028	$	57,296	$	12,848
2029 through 2033	$	286,471	$	59,299


For the year ending:	(Thousands of dollars)
2024	$	27,843
2025	$	29,391
2026	$	31,025
2027	$	32,751
2028	$	34,572


(1) Consolidated Financial Statements			Page No.

	(a)	Report of Independent Registered Public Accounting Firm (PCAOB ID: 238)	39

	(b)	Consolidated Statements of Income for the years ended December 31, 2023, 2022 and 2021	42

	(c)	Consolidated Statements of Comprehensive Income for the years ended December 31, 2023, 2022 and 2021	43

	(d)	Consolidated Balance Sheets as of December 31, 2023 and 2022	44

	(e)	Consolidated Statements of Cash Flows for the years ended December 31, 2023, 2022 and 2021	46

	(f)	Consolidated Statements of Equity for the years ended December 31, 2023, 2022 and 2021	48

	(g)	Notes to Consolidated Financial Statements	49

(2) Consolidated Financial Statements Schedules

All schedules have been omitted because of the absence of conditions under which they are required.


(3) Exhibits

	3.1	Amended and Restated Certificate of Incorporation of ONE Gas, Inc., dated May 24, 2018 (incorporated by reference to Exhibit 3.1 to ONE Gas, Inc.’s Current Report on Form 8-K filed on May 30, 2018 (File No. 1-36108)).

	3.2	Amended and Restated By-Laws of ONE Gas, Inc. dated February 21, 2023 (incorporated by reference to Exhibit 3.1 to ONE Gas, Inc.’s Current Report on Form 8-K filed on February 21, 2023 (File No. 1-36108)).

	3.3	Amended and Restated Limited Liability Company Agreement of Kansas Gas Service Securitization I, L.L.C., dated as of November 16, 2022 (incorporated by reference to Exhibit 3.3 to ONE Gas, Inc.’s Current Report on Form 8-K filed on November 18, 2022 (File No. 1-36108)).

	4.1	Form of Common Stock Certificate (incorporated by reference to Exhibit 4.2 to ONE Gas, Inc.’s Registration Statement on Form 10, Amendment No. 2 filed on December 23, 2013 (File No. 1-36108)).

	4.2	Indenture, dated January 27, 2014, between ONE Gas, Inc. and U.S. Bank National Association, as trustee (incorporated by reference to Exhibit 10.1 to ONE Gas, Inc.’s Current Report on Form 8-K filed on January 30, 2014 (File No. 1-36108)).

	4.3	Supplemental Indenture No. 1, dated January 27, 2014, between ONE Gas, Inc. and U.S. Bank National Association, as trustee, with respect to the 2.070% Senior Notes due 2019, the 3.610% Senior Notes due 2024 and the 4.685% Senior Notes due 2044-(incorporated by reference to Exhibit 10.2 to ONE Gas, Inc.’s Current Report on Form 8-K filed on January 30, 2014 (File No. 1-36108)).

	4.4	Supplemental Indenture No. 2, dated November 5, 2018, among ONE Gas, Inc. and U.S. Bank National Bank Association, as trustee, with respect to the 4.50% Senior Notes due 2048 (incorporated by reference to Exhibit 4.2 to ONE Gas, Inc.’s Current Report on Form 8-K filed on November 6, 2018 (File No. 1-36108)).