wtm-20230630
000077686712/312023Q2false00007768672023-01-012023-06-3000007768672023-08-03xbrli:shares0000776867wtm:HgGlobalBamMember2023-06-30iso4217:USD0000776867wtm:HgGlobalBamMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMember2022-12-310000776867wtm:KuduMember2023-06-300000776867wtm:KuduMember2022-12-310000776867wtm:KuduInvestmentManagementLLCMember2023-06-300000776867wtm:KuduInvestmentManagementLLCMember2022-12-310000776867us-gaap:CorporateAndOtherMember2023-06-300000776867us-gaap:CorporateAndOtherMember2022-12-3100007768672023-06-3000007768672022-12-31iso4217:USDxbrli:shares0000776867wtm:HgGlobalBamMember2023-04-012023-06-300000776867wtm:HgGlobalBamMember2022-04-012022-06-300000776867wtm:HgGlobalBamMember2023-01-012023-06-300000776867wtm:HgGlobalBamMember2022-01-012022-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMember2023-04-012023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMember2022-04-012022-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMember2023-01-012023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMember2022-01-012022-06-300000776867wtm:KuduMember2023-04-012023-06-300000776867wtm:KuduMember2022-04-012022-06-300000776867wtm:KuduMember2023-01-012023-06-300000776867wtm:KuduMember2022-01-012022-06-300000776867us-gaap:CorporateAndOtherMember2023-04-012023-06-300000776867us-gaap:CorporateAndOtherMember2022-04-012022-06-300000776867us-gaap:CorporateAndOtherMember2023-01-012023-06-300000776867us-gaap:CorporateAndOtherMember2022-01-012022-06-3000007768672023-04-012023-06-3000007768672022-04-012022-06-3000007768672022-01-012022-06-300000776867us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember2023-03-310000776867us-gaap:RetainedEarningsMember2023-03-310000776867us-gaap:AccumulatedOtherComprehensiveIncomeMember2023-03-310000776867us-gaap:ParentMember2023-03-310000776867us-gaap:NoncontrollingInterestMember2023-03-310000776867wtm:TotalEquityIncludesNoncontrollingInterestMember2023-03-310000776867us-gaap:RetainedEarningsMember2023-04-012023-06-300000776867us-gaap:ParentMember2023-04-012023-06-300000776867us-gaap:NoncontrollingInterestMember2023-04-012023-06-300000776867wtm:TotalEquityIncludesNoncontrollingInterestMember2023-04-012023-06-300000776867us-gaap:AccumulatedOtherComprehensiveIncomeMember2023-04-012023-06-300000776867us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember2023-04-012023-06-300000776867wtm:BamMemberus-gaap:NoncontrollingInterestMember2023-04-012023-06-300000776867wtm:BamMemberwtm:TotalEquityIncludesNoncontrollingInterestMember2023-04-012023-06-300000776867us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember2023-06-300000776867us-gaap:RetainedEarningsMember2023-06-300000776867us-gaap:AccumulatedOtherComprehensiveIncomeMember2023-06-300000776867us-gaap:ParentMember2023-06-300000776867us-gaap:NoncontrollingInterestMember2023-06-300000776867wtm:TotalEquityIncludesNoncontrollingInterestMember2023-06-300000776867us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember2022-03-310000776867us-gaap:RetainedEarningsMember2022-03-310000776867us-gaap:AccumulatedOtherComprehensiveIncomeMember2022-03-310000776867us-gaap:ParentMember2022-03-310000776867us-gaap:NoncontrollingInterestMember2022-03-310000776867wtm:TotalEquityIncludesNoncontrollingInterestMember2022-03-310000776867us-gaap:RetainedEarningsMember2022-04-012022-06-300000776867us-gaap:ParentMember2022-04-012022-06-300000776867us-gaap:NoncontrollingInterestMember2022-04-012022-06-300000776867wtm:TotalEquityIncludesNoncontrollingInterestMember2022-04-012022-06-300000776867us-gaap:AccumulatedOtherComprehensiveIncomeMember2022-04-012022-06-300000776867us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember2022-04-012022-06-300000776867wtm:BamMemberus-gaap:NoncontrollingInterestMember2022-04-012022-06-300000776867wtm:BamMemberwtm:TotalEquityIncludesNoncontrollingInterestMember2022-04-012022-06-300000776867us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember2022-06-300000776867us-gaap:RetainedEarningsMember2022-06-300000776867us-gaap:AccumulatedOtherComprehensiveIncomeMember2022-06-300000776867us-gaap:ParentMember2022-06-300000776867us-gaap:NoncontrollingInterestMember2022-06-300000776867wtm:TotalEquityIncludesNoncontrollingInterestMember2022-06-300000776867us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember2022-12-310000776867us-gaap:RetainedEarningsMember2022-12-310000776867us-gaap:AccumulatedOtherComprehensiveIncomeMember2022-12-310000776867us-gaap:ParentMember2022-12-310000776867us-gaap:NoncontrollingInterestMember2022-12-310000776867wtm:TotalEquityIncludesNoncontrollingInterestMember2022-12-310000776867us-gaap:RetainedEarningsMember2023-01-012023-06-300000776867us-gaap:ParentMember2023-01-012023-06-300000776867us-gaap:NoncontrollingInterestMember2023-01-012023-06-300000776867wtm:TotalEquityIncludesNoncontrollingInterestMember2023-01-012023-06-300000776867us-gaap:AccumulatedOtherComprehensiveIncomeMember2023-01-012023-06-300000776867us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember2023-01-012023-06-300000776867wtm:BamMemberus-gaap:NoncontrollingInterestMember2023-01-012023-06-300000776867wtm:BamMemberwtm:TotalEquityIncludesNoncontrollingInterestMember2023-01-012023-06-300000776867us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember2021-12-310000776867us-gaap:RetainedEarningsMember2021-12-310000776867us-gaap:AccumulatedOtherComprehensiveIncomeMember2021-12-310000776867us-gaap:ParentMember2021-12-310000776867us-gaap:NoncontrollingInterestMember2021-12-310000776867wtm:TotalEquityIncludesNoncontrollingInterestMember2021-12-310000776867us-gaap:RetainedEarningsMember2022-01-012022-06-300000776867us-gaap:ParentMember2022-01-012022-06-300000776867us-gaap:NoncontrollingInterestMember2022-01-012022-06-300000776867wtm:TotalEquityIncludesNoncontrollingInterestMember2022-01-012022-06-300000776867us-gaap:AccumulatedOtherComprehensiveIncomeMember2022-01-012022-06-300000776867us-gaap:CommonStockIncludingAdditionalPaidInCapitalMember2022-01-012022-06-300000776867wtm:BamMemberus-gaap:NoncontrollingInterestMember2022-01-012022-06-300000776867wtm:BamMemberwtm:TotalEquityIncludesNoncontrollingInterestMember2022-01-012022-06-300000776867wtm:MediaAlphaMember2023-01-012023-06-300000776867wtm:MediaAlphaMember2022-01-012022-06-300000776867wtm:OtherEntityMember2023-01-012023-06-300000776867wtm:OtherEntityMember2022-01-012022-06-3000007768672021-12-310000776867wtm:NSMInsuranceGroupMemberus-gaap:DiscontinuedOperationsHeldforsaleMember2022-12-310000776867wtm:NSMInsuranceGroupMemberus-gaap:DiscontinuedOperationsHeldforsaleMember2021-12-3100007768672022-06-300000776867wtm:NSMInsuranceGroupMemberus-gaap:DiscontinuedOperationsHeldforsaleMember2023-06-300000776867wtm:NSMInsuranceGroupMemberus-gaap:DiscontinuedOperationsHeldforsaleMember2022-06-30wtm:segment0000776867wtm:HgGlobalMember2023-06-30xbrli:pure0000776867wtm:HgGlobalMember2012-07-310000776867wtm:HgGlobalMemberus-gaap:PreferredStockMember2022-12-310000776867wtm:HgGlobalMemberus-gaap:PreferredStockMember2023-06-300000776867wtm:HgGlobalMemberus-gaap:CommonStockMember2023-06-300000776867wtm:HgGlobalMemberus-gaap:CommonStockMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedMemberwtm:ArkInsuranceHoldingsLimitedMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedMemberwtm:ArkInsuranceHoldingsLimitedMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedMemberwtm:ArkInsuranceHoldingsLimitedMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedMemberwtm:ArkInsuranceHoldingsLimitedMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedMember2023-01-012023-06-300000776867wtm:OutriggerReMemberus-gaap:PreferredStockMember2022-12-310000776867wtm:OutriggerReMemberus-gaap:PreferredStockMember2023-06-300000776867wtm:KuduInvestmentManagementLLCMember2023-06-300000776867wtm:KuduInvestmentManagementLLCMember2022-12-310000776867wtm:NSMInsuranceGroupMemberus-gaap:DiscontinuedOperationsDisposedOfBySaleMember2022-08-010000776867wtm:NSMInsuranceGroupMemberus-gaap:DiscontinuedOperationsDisposedOfBySaleMember2022-08-012022-08-010000776867wtm:OutriggerReMember2022-12-202022-12-200000776867wtm:OutriggerReMember2022-10-012022-12-310000776867wtm:KuduMember2022-05-262022-05-260000776867wtm:MassMutualMember2022-05-262022-05-260000776867wtm:WhiteMountainsMember2022-05-262022-05-260000776867wtm:KuduInvestmentManagementLLCMember2022-05-262022-05-260000776867wtm:KuduMember2022-05-262022-05-260000776867wtm:KuduMember2021-01-012021-12-310000776867wtm:KuduMember2022-05-250000776867wtm:KuduMember2022-05-260000776867us-gaap:FixedMaturitiesMember2023-04-012023-06-300000776867us-gaap:FixedMaturitiesMember2022-04-012022-06-300000776867us-gaap:FixedMaturitiesMember2023-01-012023-06-300000776867us-gaap:FixedMaturitiesMember2022-01-012022-06-300000776867us-gaap:ShortTermInvestmentsMember2023-04-012023-06-300000776867us-gaap:ShortTermInvestmentsMember2022-04-012022-06-300000776867us-gaap:ShortTermInvestmentsMember2023-01-012023-06-300000776867us-gaap:ShortTermInvestmentsMember2022-01-012022-06-300000776867us-gaap:CommonStockMember2023-04-012023-06-300000776867us-gaap:CommonStockMember2022-04-012022-06-300000776867us-gaap:CommonStockMember2023-01-012023-06-300000776867us-gaap:CommonStockMember2022-01-012022-06-300000776867us-gaap:OtherLongTermInvestmentsMember2023-04-012023-06-300000776867us-gaap:OtherLongTermInvestmentsMember2022-04-012022-06-300000776867us-gaap:OtherLongTermInvestmentsMember2023-01-012023-06-300000776867us-gaap:OtherLongTermInvestmentsMember2022-01-012022-06-300000776867wtm:TPCProvidersMember2023-04-012023-06-300000776867wtm:TPCProvidersMember2022-04-012022-06-300000776867wtm:TPCProvidersMember2023-01-012023-06-300000776867wtm:TPCProvidersMember2022-01-012022-06-300000776867wtm:MediaAlphaMember2023-04-012023-06-300000776867wtm:MediaAlphaMember2022-04-012022-06-300000776867wtm:MediaAlphaMember2023-01-012023-06-300000776867wtm:MediaAlphaMember2022-01-012022-06-300000776867wtm:TotalInvestmentsMember2023-04-012023-06-300000776867wtm:TotalInvestmentsMember2022-04-012022-06-300000776867wtm:TotalInvestmentsMember2023-01-012023-06-300000776867wtm:TotalInvestmentsMember2022-01-012022-06-300000776867wtm:InvestmentsHeldMember2023-04-012023-06-300000776867wtm:InvestmentsHeldMember2022-04-012022-06-300000776867wtm:InvestmentsHeldMember2023-01-012023-06-300000776867wtm:InvestmentsHeldMember2022-01-012022-06-300000776867wtm:FixedMaturitiesAndShortTermInvestmentsMember2023-04-012023-06-300000776867wtm:FixedMaturitiesAndShortTermInvestmentsMember2022-04-012022-06-300000776867wtm:FixedMaturitiesAndShortTermInvestmentsMember2023-01-012023-06-300000776867wtm:FixedMaturitiesAndShortTermInvestmentsMember2022-01-012022-06-300000776867wtm:FixedMaturitiesAndShortTermInvestmentsMemberwtm:InvestmentsHeldMember2023-04-012023-06-300000776867wtm:FixedMaturitiesAndShortTermInvestmentsMemberwtm:InvestmentsHeldMember2022-04-012022-06-300000776867wtm:FixedMaturitiesAndShortTermInvestmentsMemberwtm:InvestmentsHeldMember2023-01-012023-06-300000776867wtm:FixedMaturitiesAndShortTermInvestmentsMemberwtm:InvestmentsHeldMember2022-01-012022-06-300000776867wtm:CommonEquitySecuritiesAndInvestmentInMediaAlphaMember2023-04-012023-06-300000776867wtm:CommonEquitySecuritiesAndInvestmentInMediaAlphaMember2022-04-012022-06-300000776867wtm:CommonEquitySecuritiesAndInvestmentInMediaAlphaMember2023-01-012023-06-300000776867wtm:CommonEquitySecuritiesAndInvestmentInMediaAlphaMember2022-01-012022-06-300000776867wtm:InvestmentsHeldMemberwtm:CommonEquitySecuritiesAndInvestmentInMediaAlphaMember2023-04-012023-06-300000776867wtm:InvestmentsHeldMemberwtm:CommonEquitySecuritiesAndInvestmentInMediaAlphaMember2022-04-012022-06-300000776867wtm:InvestmentsHeldMemberwtm:CommonEquitySecuritiesAndInvestmentInMediaAlphaMember2023-01-012023-06-300000776867wtm:InvestmentsHeldMemberwtm:CommonEquitySecuritiesAndInvestmentInMediaAlphaMember2022-01-012022-06-300000776867us-gaap:FairValueInputsLevel3Memberus-gaap:OtherLongTermInvestmentsMember2023-04-012023-06-300000776867us-gaap:FairValueInputsLevel3Memberus-gaap:OtherLongTermInvestmentsMember2022-04-012022-06-300000776867us-gaap:FairValueInputsLevel3Memberus-gaap:OtherLongTermInvestmentsMember2023-01-012023-06-300000776867us-gaap:FairValueInputsLevel3Memberus-gaap:OtherLongTermInvestmentsMember2022-01-012022-06-300000776867us-gaap:USTreasuryAndGovernmentMember2023-06-300000776867us-gaap:USTreasuryAndGovernmentMember2023-01-012023-06-300000776867us-gaap:CorporateDebtSecuritiesMember2023-06-300000776867us-gaap:CorporateDebtSecuritiesMember2023-01-012023-06-300000776867us-gaap:MunicipalBondsMember2023-06-300000776867us-gaap:MunicipalBondsMember2023-01-012023-06-300000776867us-gaap:AssetBackedSecuritiesMember2023-06-300000776867us-gaap:AssetBackedSecuritiesMember2023-01-012023-06-300000776867us-gaap:CollateralizedLoanObligationsMember2023-06-300000776867us-gaap:CollateralizedLoanObligationsMember2023-01-012023-06-300000776867us-gaap:FixedIncomeInvestmentsMember2023-06-300000776867us-gaap:FixedIncomeInvestmentsMember2023-01-012023-06-300000776867us-gaap:USTreasuryAndGovernmentMember2022-12-310000776867us-gaap:USTreasuryAndGovernmentMember2022-01-012022-12-310000776867us-gaap:CorporateDebtSecuritiesMember2022-12-310000776867us-gaap:CorporateDebtSecuritiesMember2022-01-012022-12-310000776867us-gaap:MunicipalBondsMember2022-12-310000776867us-gaap:MunicipalBondsMember2022-01-012022-12-310000776867us-gaap:AssetBackedSecuritiesMember2022-12-310000776867us-gaap:AssetBackedSecuritiesMember2022-01-012022-12-310000776867us-gaap:CollateralizedLoanObligationsMember2022-12-310000776867us-gaap:CollateralizedLoanObligationsMember2022-01-012022-12-310000776867us-gaap:FixedIncomeInvestmentsMember2022-12-310000776867us-gaap:FixedIncomeInvestmentsMember2022-01-012022-12-310000776867wtm:FixedMaturitiesAndConvertibleFixedMaturitiesExcludingMortgageBackedSecuritesAssetBackedSecuritiesAndPreferredStockMember2023-06-300000776867us-gaap:CommonStockMember2023-06-300000776867wtm:MediaAlphaMember2023-06-300000776867wtm:OtherLongTermInvestmentsExcludingEquityMethodInvestmentsMember2023-06-300000776867wtm:OtherLongTermInvestmentsExcludingEquityMethodInvestmentsMember2023-01-012023-06-300000776867us-gaap:CommonStockMember2022-12-310000776867us-gaap:CommonStockMember2022-01-012022-12-310000776867wtm:MediaAlphaMember2022-12-310000776867wtm:MediaAlphaMember2022-01-012022-12-310000776867wtm:OtherLongTermInvestmentsExcludingEquityMethodInvestmentsMember2022-12-310000776867wtm:OtherLongTermInvestmentsExcludingEquityMethodInvestmentsMember2022-01-012022-12-3100007768672022-01-012022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:USTreasuryAndGovernmentMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Memberus-gaap:USTreasuryAndGovernmentMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Memberus-gaap:USTreasuryAndGovernmentMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:USTreasuryAndGovernmentMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:FinancialsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Memberwtm:FinancialsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Memberwtm:FinancialsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:FinancialsMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:ConsumerMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Memberwtm:ConsumerMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Memberwtm:ConsumerMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel3Memberwtm:ConsumerMember2023-06-300000776867us-gaap:HealthCareMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMember2023-06-300000776867us-gaap:HealthCareMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Member2023-06-300000776867us-gaap:HealthCareMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867us-gaap:HealthCareMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:TechnologyMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Memberwtm:TechnologyMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Memberwtm:TechnologyMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel3Memberwtm:TechnologyMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:IndustrialMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Memberwtm:IndustrialMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Memberwtm:IndustrialMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel3Memberwtm:IndustrialMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:UtilitiesMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Memberwtm:UtilitiesMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Memberwtm:UtilitiesMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:UtilitiesMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:CommunicationsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Memberwtm:CommunicationsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Memberwtm:CommunicationsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel3Memberwtm:CommunicationsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:EnergyMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:EnergyMemberus-gaap:FairValueInputsLevel1Member2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:EnergyMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:EnergyMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:BasicMaterialsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Memberwtm:BasicMaterialsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Memberwtm:BasicMaterialsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel3Memberwtm:BasicMaterialsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Member2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:MunicipalBondsMemberus-gaap:FairValueMeasurementsRecurringMember2023-06-300000776867us-gaap:MunicipalBondsMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2023-06-300000776867us-gaap:MunicipalBondsMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867us-gaap:MunicipalBondsMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:AssetBackedSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMember2023-06-300000776867us-gaap:AssetBackedSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2023-06-300000776867us-gaap:AssetBackedSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867us-gaap:AssetBackedSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CollateralizedLoanObligationsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Memberus-gaap:CollateralizedLoanObligationsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Memberus-gaap:CollateralizedLoanObligationsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Memberus-gaap:CollateralizedLoanObligationsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FixedMaturitiesMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Memberus-gaap:FixedMaturitiesMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Memberus-gaap:FixedMaturitiesMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FixedMaturitiesMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:ShortTermInvestmentsMemberus-gaap:FairValueMeasurementsRecurringMember2023-06-300000776867us-gaap:ShortTermInvestmentsMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2023-06-300000776867us-gaap:ShortTermInvestmentsMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867us-gaap:ShortTermInvestmentsMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:ExchangeTradedFundsMember2023-06-300000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Memberus-gaap:ExchangeTradedFundsMember2023-06-300000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Memberus-gaap:ExchangeTradedFundsMember2023-06-300000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Memberus-gaap:ExchangeTradedFundsMember2023-06-300000776867us-gaap:EquitySecuritiesMemberwtm:OtherSectorMemberus-gaap:FairValueMeasurementsRecurringMember2023-06-300000776867us-gaap:EquitySecuritiesMemberwtm:OtherSectorMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2023-06-300000776867us-gaap:EquitySecuritiesMemberwtm:OtherSectorMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867us-gaap:EquitySecuritiesMemberwtm:OtherSectorMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMember2023-06-300000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2023-06-300000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867wtm:MediaAlphaMemberus-gaap:FairValueMeasurementsRecurringMember2023-06-300000776867wtm:MediaAlphaMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2023-06-300000776867wtm:MediaAlphaMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867wtm:MediaAlphaMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:OtherLongTermInvestmentsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherLongTermInvestmentsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Memberus-gaap:OtherLongTermInvestmentsMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Memberus-gaap:OtherLongTermInvestmentsMember2023-06-300000776867wtm:OtherLongTermInvestmentNAVMemberus-gaap:FairValueMeasurementsRecurringMember2023-06-300000776867wtm:OtherLongTermInvestmentNAVMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2023-06-300000776867wtm:OtherLongTermInvestmentNAVMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867wtm:OtherLongTermInvestmentNAVMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMember2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:USTreasuryAndGovernmentMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Memberus-gaap:USTreasuryAndGovernmentMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Memberus-gaap:USTreasuryAndGovernmentMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:USTreasuryAndGovernmentMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:FinancialsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Memberwtm:FinancialsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Memberwtm:FinancialsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:FinancialsMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:ConsumerMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Memberwtm:ConsumerMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Memberwtm:ConsumerMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel3Memberwtm:ConsumerMember2022-12-310000776867us-gaap:HealthCareMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMember2022-12-310000776867us-gaap:HealthCareMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Member2022-12-310000776867us-gaap:HealthCareMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867us-gaap:HealthCareMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:TechnologyMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Memberwtm:TechnologyMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Memberwtm:TechnologyMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel3Memberwtm:TechnologyMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:IndustrialMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Memberwtm:IndustrialMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Memberwtm:IndustrialMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel3Memberwtm:IndustrialMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:UtilitiesMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Memberwtm:UtilitiesMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Memberwtm:UtilitiesMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:UtilitiesMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:CommunicationsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Memberwtm:CommunicationsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Memberwtm:CommunicationsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel3Memberwtm:CommunicationsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:EnergyMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:EnergyMemberus-gaap:FairValueInputsLevel1Member2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:EnergyMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:EnergyMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberwtm:BasicMaterialsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Memberwtm:BasicMaterialsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Memberwtm:BasicMaterialsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel3Memberwtm:BasicMaterialsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel1Member2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:MunicipalBondsMemberus-gaap:FairValueMeasurementsRecurringMember2022-12-310000776867us-gaap:MunicipalBondsMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2022-12-310000776867us-gaap:MunicipalBondsMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867us-gaap:MunicipalBondsMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:AssetBackedSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMember2022-12-310000776867us-gaap:AssetBackedSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2022-12-310000776867us-gaap:AssetBackedSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867us-gaap:AssetBackedSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:CollateralizedLoanObligationsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Memberus-gaap:CollateralizedLoanObligationsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Memberus-gaap:CollateralizedLoanObligationsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Memberus-gaap:CollateralizedLoanObligationsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FixedMaturitiesMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Memberus-gaap:FixedMaturitiesMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Memberus-gaap:FixedMaturitiesMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FixedMaturitiesMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:ShortTermInvestmentsMemberus-gaap:FairValueMeasurementsRecurringMember2022-12-310000776867us-gaap:ShortTermInvestmentsMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2022-12-310000776867us-gaap:ShortTermInvestmentsMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867us-gaap:ShortTermInvestmentsMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:ExchangeTradedFundsMember2022-12-310000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Memberus-gaap:ExchangeTradedFundsMember2022-12-310000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Memberus-gaap:ExchangeTradedFundsMember2022-12-310000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Memberus-gaap:ExchangeTradedFundsMember2022-12-310000776867us-gaap:EquitySecuritiesMemberwtm:OtherSectorMemberus-gaap:FairValueMeasurementsRecurringMember2022-12-310000776867us-gaap:EquitySecuritiesMemberwtm:OtherSectorMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2022-12-310000776867us-gaap:EquitySecuritiesMemberwtm:OtherSectorMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867us-gaap:EquitySecuritiesMemberwtm:OtherSectorMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMember2022-12-310000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2022-12-310000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867us-gaap:EquitySecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867wtm:MediaAlphaMemberus-gaap:FairValueMeasurementsRecurringMember2022-12-310000776867wtm:MediaAlphaMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2022-12-310000776867wtm:MediaAlphaMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867wtm:MediaAlphaMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:OtherLongTermInvestmentsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Memberus-gaap:OtherLongTermInvestmentsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Memberus-gaap:OtherLongTermInvestmentsMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Memberus-gaap:OtherLongTermInvestmentsMember2022-12-310000776867wtm:OtherLongTermInvestmentNAVMemberus-gaap:FairValueMeasurementsRecurringMember2022-12-310000776867wtm:OtherLongTermInvestmentNAVMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2022-12-310000776867wtm:OtherLongTermInvestmentNAVMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867wtm:OtherLongTermInvestmentNAVMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMember2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:SeniorNotesMemberus-gaap:SecuredDebtMember2023-06-300000776867us-gaap:SeniorNotesMemberus-gaap:SecuredDebtMember2022-12-310000776867wtm:ForeignRegulatoryDepositsMember2023-06-300000776867wtm:ForeignRegulatoryDepositsMember2022-12-310000776867wtm:LloydsBankMember2023-06-300000776867wtm:LloydsBankMember2022-12-310000776867us-gaap:AssetPledgedAsCollateralMemberwtm:AdditionalInvestmentsInsuranceRegulatorsAndReinsuranceCounterpartiesMember2023-06-300000776867us-gaap:AssetPledgedAsCollateralMemberwtm:AdditionalInvestmentsInsuranceRegulatorsAndReinsuranceCounterpartiesMember2022-12-310000776867us-gaap:ShortTermInvestmentsMemberus-gaap:AssetPledgedAsCollateralMember2023-06-300000776867us-gaap:ShortTermInvestmentsMemberus-gaap:AssetPledgedAsCollateralMember2022-12-310000776867wtm:CashAndShortTermInvestmentsMemberwtm:OutriggerReMember2023-06-300000776867wtm:CashAndShortTermInvestmentsMemberwtm:OutriggerReMember2022-12-310000776867srt:StandardPoorsAAARatingMemberus-gaap:CorporateDebtSecuritiesMember2023-06-300000776867srt:StandardPoorsAAARatingMemberus-gaap:CorporateDebtSecuritiesMember2022-12-310000776867srt:StandardPoorsAARatingMemberus-gaap:CorporateDebtSecuritiesMember2023-06-300000776867srt:StandardPoorsAARatingMemberus-gaap:CorporateDebtSecuritiesMember2022-12-310000776867us-gaap:CorporateDebtSecuritiesMembersrt:StandardPoorsARatingMember2023-06-300000776867us-gaap:CorporateDebtSecuritiesMembersrt:StandardPoorsARatingMember2022-12-310000776867us-gaap:CorporateDebtSecuritiesMembersrt:StandardPoorsBBBRatingMember2023-06-300000776867us-gaap:CorporateDebtSecuritiesMembersrt:StandardPoorsBBBRatingMember2022-12-310000776867wtm:StandardPoorsOtherMemberus-gaap:CorporateDebtSecuritiesMember2023-06-300000776867wtm:StandardPoorsOtherMemberus-gaap:CorporateDebtSecuritiesMember2022-12-310000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FederalNationalMortgageAssociationCertificatesAndObligationsFNMAMember2023-06-300000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Memberus-gaap:FederalNationalMortgageAssociationCertificatesAndObligationsFNMAMember2023-06-300000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Memberus-gaap:FederalNationalMortgageAssociationCertificatesAndObligationsFNMAMember2023-06-300000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FederalNationalMortgageAssociationCertificatesAndObligationsFNMAMember2022-12-310000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Memberus-gaap:FederalNationalMortgageAssociationCertificatesAndObligationsFNMAMember2022-12-310000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Memberus-gaap:FederalNationalMortgageAssociationCertificatesAndObligationsFNMAMember2022-12-310000776867us-gaap:FederalHomeLoanMortgageCorporationCertificatesAndObligationsFHLMCMemberus-gaap:MortgageBackedSecuritiesMember2023-06-300000776867us-gaap:FederalHomeLoanMortgageCorporationCertificatesAndObligationsFHLMCMemberus-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867us-gaap:FederalHomeLoanMortgageCorporationCertificatesAndObligationsFHLMCMemberus-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:FederalHomeLoanMortgageCorporationCertificatesAndObligationsFHLMCMemberus-gaap:MortgageBackedSecuritiesMember2022-12-310000776867us-gaap:FederalHomeLoanMortgageCorporationCertificatesAndObligationsFHLMCMemberus-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867us-gaap:FederalHomeLoanMortgageCorporationCertificatesAndObligationsFHLMCMemberus-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:GovernmentNationalMortgageAssociationCertificatesAndObligationsGNMAMember2023-06-300000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Memberus-gaap:GovernmentNationalMortgageAssociationCertificatesAndObligationsGNMAMember2023-06-300000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Memberus-gaap:GovernmentNationalMortgageAssociationCertificatesAndObligationsGNMAMember2023-06-300000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:GovernmentNationalMortgageAssociationCertificatesAndObligationsGNMAMember2022-12-310000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Memberus-gaap:GovernmentNationalMortgageAssociationCertificatesAndObligationsGNMAMember2022-12-310000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Memberus-gaap:GovernmentNationalMortgageAssociationCertificatesAndObligationsGNMAMember2022-12-310000776867us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMemberus-gaap:MortgageBackedSecuritiesMember2023-06-300000776867us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMemberus-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMemberus-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMemberus-gaap:MortgageBackedSecuritiesMember2022-12-310000776867us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMemberus-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMemberus-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:ResidentialMortgageBackedSecuritiesMember2023-06-300000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Memberus-gaap:ResidentialMortgageBackedSecuritiesMember2023-06-300000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Memberus-gaap:ResidentialMortgageBackedSecuritiesMember2023-06-300000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:ResidentialMortgageBackedSecuritiesMember2022-12-310000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Memberus-gaap:ResidentialMortgageBackedSecuritiesMember2022-12-310000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Memberus-gaap:ResidentialMortgageBackedSecuritiesMember2022-12-310000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember2023-06-300000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Memberus-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember2023-06-300000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Memberus-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember2023-06-300000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember2022-12-310000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Memberus-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember2022-12-310000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Memberus-gaap:MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember2022-12-310000776867us-gaap:MortgageBackedSecuritiesMember2023-06-300000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:MortgageBackedSecuritiesMember2022-12-310000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867us-gaap:MortgageBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:CollateralizedCreditCardSecuritiesMember2023-06-300000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:FairValueInputsLevel2Memberus-gaap:CollateralizedCreditCardSecuritiesMember2023-06-300000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:FairValueInputsLevel3Memberus-gaap:CollateralizedCreditCardSecuritiesMember2023-06-300000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:CollateralizedCreditCardSecuritiesMember2022-12-310000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:FairValueInputsLevel2Memberus-gaap:CollateralizedCreditCardSecuritiesMember2022-12-310000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:FairValueInputsLevel3Memberus-gaap:CollateralizedCreditCardSecuritiesMember2022-12-310000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:CollateralizedAutoLoansMember2023-06-300000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:FairValueInputsLevel2Memberus-gaap:CollateralizedAutoLoansMember2023-06-300000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:CollateralizedAutoLoansMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:CollateralizedAutoLoansMember2022-12-310000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:FairValueInputsLevel2Memberus-gaap:CollateralizedAutoLoansMember2022-12-310000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:CollateralizedAutoLoansMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember2023-06-300000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember2022-12-310000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867us-gaap:AssetBackedSecuritiesSecuritizedLoansAndReceivablesMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:AssetBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Member2023-06-300000776867us-gaap:AssetBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Member2023-06-300000776867us-gaap:AssetBackedSecuritiesMemberus-gaap:FairValueInputsLevel2Member2022-12-310000776867us-gaap:AssetBackedSecuritiesMemberus-gaap:FairValueInputsLevel3Member2022-12-310000776867us-gaap:FairValueInputsLevel2Memberus-gaap:CollateralizedLoanObligationsMember2023-06-300000776867us-gaap:FairValueInputsLevel3Memberus-gaap:CollateralizedLoanObligationsMember2023-06-300000776867us-gaap:FairValueInputsLevel2Memberus-gaap:CollateralizedLoanObligationsMember2022-12-310000776867us-gaap:FairValueInputsLevel3Memberus-gaap:CollateralizedLoanObligationsMember2022-12-310000776867wtm:MortgageAndAssetBackedSecuritiesAndCollateralizedLoanObligationsMember2023-06-300000776867us-gaap:FairValueInputsLevel2Memberwtm:MortgageAndAssetBackedSecuritiesAndCollateralizedLoanObligationsMember2023-06-300000776867us-gaap:FairValueInputsLevel3Memberwtm:MortgageAndAssetBackedSecuritiesAndCollateralizedLoanObligationsMember2023-06-300000776867wtm:MortgageAndAssetBackedSecuritiesAndCollateralizedLoanObligationsMember2022-12-310000776867us-gaap:FairValueInputsLevel2Memberwtm:MortgageAndAssetBackedSecuritiesAndCollateralizedLoanObligationsMember2022-12-310000776867us-gaap:FairValueInputsLevel3Memberwtm:MortgageAndAssetBackedSecuritiesAndCollateralizedLoanObligationsMember2022-12-310000776867us-gaap:CollateralizedMortgageObligationsMemberus-gaap:MortgageBackedSecuritiesMember2023-06-300000776867wtm:MediaAlphaMember2023-04-012023-06-300000776867wtm:MediaAlphaMember2023-06-300000776867wtm:MediaAlphaMember2023-06-300000776867us-gaap:IPOMemberwtm:MediaAlphaMember2023-01-012023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:KuduInvestmentManagementLLCMember2023-06-300000776867wtm:KuduMemberwtm:KuduInvestmentManagementLLCMember2023-06-300000776867us-gaap:CorporateAndOtherMemberwtm:KuduInvestmentManagementLLCMember2023-06-300000776867wtm:KuduInvestmentManagementLLCMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:DavidShieldPassportCardMember2023-06-300000776867wtm:DavidShieldPassportCardMemberwtm:KuduMember2023-06-300000776867wtm:DavidShieldPassportCardMemberus-gaap:CorporateAndOtherMember2023-06-300000776867wtm:DavidShieldPassportCardMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:ElementumHoldingsL.P.Member2023-06-300000776867wtm:ElementumHoldingsL.P.Memberwtm:KuduMember2023-06-300000776867us-gaap:CorporateAndOtherMemberwtm:ElementumHoldingsL.P.Member2023-06-300000776867wtm:ElementumHoldingsL.P.Member2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:OtherUnconsolidatedPrivateEquityInvestmentsMember2023-06-300000776867wtm:OtherUnconsolidatedPrivateEquityInvestmentsMemberwtm:KuduMember2023-06-300000776867us-gaap:CorporateAndOtherMemberwtm:OtherUnconsolidatedPrivateEquityInvestmentsMember2023-06-300000776867wtm:OtherUnconsolidatedPrivateEquityInvestmentsMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:TotalUnconsolidatedEntitiesMember2023-06-300000776867wtm:KuduMemberwtm:TotalUnconsolidatedEntitiesMember2023-06-300000776867us-gaap:CorporateAndOtherMemberwtm:TotalUnconsolidatedEntitiesMember2023-06-300000776867wtm:TotalUnconsolidatedEntitiesMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:HedgeFundsAndPrivateEquityFundsMember2023-06-300000776867wtm:KuduMemberwtm:HedgeFundsAndPrivateEquityFundsMember2023-06-300000776867us-gaap:CorporateAndOtherMemberwtm:HedgeFundsAndPrivateEquityFundsMember2023-06-300000776867wtm:HedgeFundsAndPrivateEquityFundsMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:BankLoanFundMember2023-06-300000776867wtm:BankLoanFundMemberwtm:KuduMember2023-06-300000776867us-gaap:CorporateAndOtherMemberwtm:BankLoanFundMember2023-06-300000776867wtm:BankLoanFundMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:InsuranceLinkedSecuritiesFundsMember2023-06-300000776867wtm:InsuranceLinkedSecuritiesFundsMemberwtm:KuduMember2023-06-300000776867us-gaap:CorporateAndOtherMemberwtm:InsuranceLinkedSecuritiesFundsMember2023-06-300000776867wtm:InsuranceLinkedSecuritiesFundsMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:ForeignRegulatoryDepositsMember2023-06-300000776867wtm:ForeignRegulatoryDepositsMemberwtm:KuduMember2023-06-300000776867wtm:ForeignRegulatoryDepositsMemberus-gaap:CorporateAndOtherMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:PrivateDebtInstrumentMember2023-06-300000776867wtm:KuduMemberwtm:PrivateDebtInstrumentMember2023-06-300000776867us-gaap:CorporateAndOtherMemberwtm:PrivateDebtInstrumentMember2023-06-300000776867wtm:PrivateDebtInstrumentMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:OtherFundsMember2023-06-300000776867wtm:OtherFundsMemberwtm:KuduMember2023-06-300000776867wtm:OtherFundsMemberus-gaap:CorporateAndOtherMember2023-06-300000776867wtm:OtherFundsMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:KuduInvestmentManagementLLCMember2022-12-310000776867wtm:KuduMemberwtm:KuduInvestmentManagementLLCMember2022-12-310000776867us-gaap:CorporateAndOtherMemberwtm:KuduInvestmentManagementLLCMember2022-12-310000776867wtm:KuduInvestmentManagementLLCMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:DavidShieldPassportCardMember2022-12-310000776867wtm:DavidShieldPassportCardMemberwtm:KuduMember2022-12-310000776867wtm:DavidShieldPassportCardMemberus-gaap:CorporateAndOtherMember2022-12-310000776867wtm:DavidShieldPassportCardMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:ElementumHoldingsL.P.Member2022-12-310000776867wtm:ElementumHoldingsL.P.Memberwtm:KuduMember2022-12-310000776867us-gaap:CorporateAndOtherMemberwtm:ElementumHoldingsL.P.Member2022-12-310000776867wtm:ElementumHoldingsL.P.Member2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:OtherUnconsolidatedPrivateEquityInvestmentsMember2022-12-310000776867wtm:OtherUnconsolidatedPrivateEquityInvestmentsMemberwtm:KuduMember2022-12-310000776867us-gaap:CorporateAndOtherMemberwtm:OtherUnconsolidatedPrivateEquityInvestmentsMember2022-12-310000776867wtm:OtherUnconsolidatedPrivateEquityInvestmentsMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:TotalUnconsolidatedEntitiesMember2022-12-310000776867wtm:KuduMemberwtm:TotalUnconsolidatedEntitiesMember2022-12-310000776867us-gaap:CorporateAndOtherMemberwtm:TotalUnconsolidatedEntitiesMember2022-12-310000776867wtm:TotalUnconsolidatedEntitiesMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:HedgeFundsAndPrivateEquityFundsMember2022-12-310000776867wtm:KuduMemberwtm:HedgeFundsAndPrivateEquityFundsMember2022-12-310000776867us-gaap:CorporateAndOtherMemberwtm:HedgeFundsAndPrivateEquityFundsMember2022-12-310000776867wtm:HedgeFundsAndPrivateEquityFundsMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:BankLoanFundMember2022-12-310000776867wtm:BankLoanFundMemberwtm:KuduMember2022-12-310000776867us-gaap:CorporateAndOtherMemberwtm:BankLoanFundMember2022-12-310000776867wtm:BankLoanFundMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:InsuranceLinkedSecuritiesFundsMember2022-12-310000776867wtm:InsuranceLinkedSecuritiesFundsMemberwtm:KuduMember2022-12-310000776867us-gaap:CorporateAndOtherMemberwtm:InsuranceLinkedSecuritiesFundsMember2022-12-310000776867wtm:InsuranceLinkedSecuritiesFundsMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:ForeignRegulatoryDepositsMember2022-12-310000776867wtm:ForeignRegulatoryDepositsMemberwtm:KuduMember2022-12-310000776867wtm:ForeignRegulatoryDepositsMemberus-gaap:CorporateAndOtherMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:PrivateDebtInstrumentMember2022-12-310000776867wtm:KuduMemberwtm:PrivateDebtInstrumentMember2022-12-310000776867us-gaap:CorporateAndOtherMemberwtm:PrivateDebtInstrumentMember2022-12-310000776867wtm:PrivateDebtInstrumentMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:OtherFundsMember2022-12-310000776867wtm:OtherFundsMemberwtm:KuduMember2022-12-310000776867wtm:OtherFundsMemberus-gaap:CorporateAndOtherMember2022-12-310000776867wtm:OtherFundsMember2022-12-310000776867us-gaap:PrivateEquityFundsMember2023-06-30wtm:fund0000776867us-gaap:HedgeFundsMember2023-06-300000776867wtm:AerospaceDefenseGovernmentMemberus-gaap:PrivateEquityFundsMember2023-06-300000776867wtm:AerospaceDefenseGovernmentMemberus-gaap:PrivateEquityFundsMember2022-12-310000776867us-gaap:PrivateEquityFundsMemberwtm:FinancialServicesMember2023-06-300000776867us-gaap:PrivateEquityFundsMemberwtm:FinancialServicesMember2022-12-310000776867us-gaap:RealEstateMemberus-gaap:PrivateEquityFundsMember2023-06-300000776867us-gaap:RealEstateMemberus-gaap:PrivateEquityFundsMember2022-12-310000776867us-gaap:PrivateEquityFundsMember2023-06-300000776867us-gaap:PrivateEquityFundsMember2022-12-310000776867us-gaap:HedgeFundsMemberwtm:HedgeFundLongShortEquityBanksandFinancialMember2023-06-300000776867us-gaap:HedgeFundsMemberwtm:HedgeFundLongShortEquityBanksandFinancialMember2022-12-310000776867us-gaap:HedgeFundsMemberwtm:HedgeFundEuropeanSmallMidCapMember2023-06-300000776867us-gaap:HedgeFundsMemberwtm:HedgeFundEuropeanSmallMidCapMember2022-12-310000776867us-gaap:HedgeFundsMember2023-06-300000776867us-gaap:HedgeFundsMember2022-12-310000776867wtm:FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLiquidatingInvestmentRemainingPeriod1To3YearsMemberus-gaap:PrivateEquityFundsMember2023-06-300000776867us-gaap:PrivateEquityFundsMemberwtm:FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLiquidatingInvestmentRemainingPeriod3To5YearsMember2023-06-300000776867us-gaap:PrivateEquityFundsMemberwtm:FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLiquidatingInvestmentRemainingPeriod5To10YearsMember2023-06-300000776867us-gaap:PrivateEquityFundsMemberwtm:FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLiquidatingInvestmentRemainingPeriodOver10YearsMember2023-06-300000776867us-gaap:HedgeFundsMembersrt:MinimumMember2023-01-012023-06-300000776867us-gaap:HedgeFundsMembersrt:MaximumMember2023-01-012023-06-300000776867wtm:InsuranceLinkedSecuritiesFundsMembersrt:MinimumMember2023-01-012023-06-300000776867srt:MaximumMemberwtm:InsuranceLinkedSecuritiesFundsMember2023-01-012023-06-300000776867us-gaap:FairValueInputsLevel3Memberus-gaap:OtherLongTermInvestmentsMember2022-12-310000776867us-gaap:FairValueInputsLevel3Memberus-gaap:OtherLongTermInvestmentsMember2021-12-310000776867us-gaap:FairValueInputsLevel3Memberus-gaap:OtherLongTermInvestmentsMember2023-06-300000776867us-gaap:FairValueInputsLevel3Memberus-gaap:OtherLongTermInvestmentsMember2022-06-300000776867us-gaap:FairValueInputsLevel3Memberus-gaap:OtherLongTermInvestmentsMemberwtm:RecentTransactionMember2023-06-300000776867us-gaap:FairValueInputsLevel3Memberus-gaap:OtherLongTermInvestmentsMemberwtm:RecentTransactionMember2022-12-310000776867wtm:DiscountedCashFlowValuationTechniqueMemberwtm:KuduInvestmentsMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMember2023-06-300000776867wtm:KuduInvestmentsMemberus-gaap:MeasurementInputDiscountRateMembersrt:MinimumMemberwtm:StandardPoorsNrRatingMember2023-01-012023-06-300000776867srt:MaximumMemberwtm:KuduInvestmentsMemberus-gaap:MeasurementInputDiscountRateMemberwtm:StandardPoorsNrRatingMember2023-01-012023-06-300000776867wtm:KuduInvestmentsMembersrt:MinimumMemberwtm:StandardPoorsNrRatingMemberwtm:TerminalMultipleMember2023-06-300000776867srt:MaximumMemberwtm:KuduInvestmentsMemberwtm:StandardPoorsNrRatingMemberwtm:TerminalMultipleMember2023-06-300000776867wtm:DiscountedCashFlowValuationTechniqueMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMemberwtm:DavidShieldPassportCardMember2023-06-300000776867us-gaap:MeasurementInputDiscountRateMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMemberwtm:DavidShieldPassportCardMember2023-01-012023-06-300000776867us-gaap:MeasurementInputLongTermRevenueGrowthRateMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMemberwtm:DavidShieldPassportCardMember2023-06-300000776867wtm:DiscountedCashFlowValuationTechniqueMemberwtm:ElementumHoldingsL.P.Memberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMember2023-06-300000776867wtm:ElementumHoldingsL.P.Memberus-gaap:MeasurementInputDiscountRateMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMember2023-01-012023-06-300000776867wtm:ElementumHoldingsL.P.Memberus-gaap:MeasurementInputLongTermRevenueGrowthRateMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMember2023-06-300000776867wtm:DiscountedCashFlowValuationTechniqueMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMemberwtm:PrivateDebtInstrumentMember2023-06-300000776867us-gaap:MeasurementInputDiscountRateMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMemberwtm:PrivateDebtInstrumentMember2023-01-012023-06-300000776867wtm:KuduParticipationContractsMemberus-gaap:MeasurementInputDiscountRateMemberwtm:StandardPoorsNrRatingMember2023-01-012023-06-300000776867wtm:KuduParticipationContractsMemberus-gaap:MeasurementInputDiscountRateMemberwtm:StandardPoorsNrRatingMember2023-06-300000776867wtm:KuduMemberwtm:KuduParticipationContractsMember2023-01-012023-06-300000776867wtm:DiscountedCashFlowValuationTechniqueMemberwtm:KuduInvestmentsMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMember2022-12-310000776867wtm:KuduInvestmentsMemberus-gaap:MeasurementInputDiscountRateMembersrt:MinimumMemberwtm:StandardPoorsNrRatingMember2022-01-012022-12-310000776867srt:MaximumMemberwtm:KuduInvestmentsMemberus-gaap:MeasurementInputDiscountRateMemberwtm:StandardPoorsNrRatingMember2022-01-012022-12-310000776867wtm:KuduInvestmentsMembersrt:MinimumMemberwtm:StandardPoorsNrRatingMemberwtm:TerminalMultipleMember2022-12-310000776867srt:MaximumMemberwtm:KuduInvestmentsMemberwtm:StandardPoorsNrRatingMemberwtm:TerminalMultipleMember2022-12-310000776867wtm:DiscountedCashFlowValuationTechniqueMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMemberwtm:DavidShieldPassportCardMember2022-12-310000776867us-gaap:MeasurementInputDiscountRateMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMemberwtm:DavidShieldPassportCardMember2022-01-012022-12-310000776867us-gaap:MeasurementInputLongTermRevenueGrowthRateMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMemberwtm:DavidShieldPassportCardMember2022-12-310000776867wtm:DiscountedCashFlowValuationTechniqueMemberwtm:ElementumHoldingsL.P.Memberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMember2022-12-310000776867wtm:ElementumHoldingsL.P.Memberus-gaap:MeasurementInputDiscountRateMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMember2022-01-012022-12-310000776867wtm:ElementumHoldingsL.P.Memberus-gaap:MeasurementInputLongTermRevenueGrowthRateMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMember2022-12-310000776867wtm:DiscountedCashFlowValuationTechniqueMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMemberwtm:PrivateDebtInstrumentMember2022-12-310000776867us-gaap:MeasurementInputDiscountRateMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMemberwtm:PrivateDebtInstrumentMember2022-01-012022-12-310000776867wtm:KuduInvestmentsMemberus-gaap:MeasurementInputDiscountRateMemberwtm:StandardPoorsNrRatingMember2022-01-012022-12-310000776867wtm:KuduInvestmentsMemberus-gaap:MeasurementInputDiscountRateMemberwtm:StandardPoorsNrRatingMember2022-12-310000776867wtm:KuduMemberwtm:KuduParticipationContractsMember2022-01-012022-12-310000776867wtm:ProbabilityWeightedExpectedReturnMethodMemberwtm:KuduInvestmentsMemberus-gaap:FairValueInputsLevel3Memberwtm:StandardPoorsNrRatingMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedMember2022-12-310000776867wtm:KuduInvestmentManagementLLCMember2023-06-300000776867wtm:KuduInvestmentManagementLLCMember2022-12-310000776867us-gaap:TradeNamesMemberwtm:KuduInvestmentManagementLLCMember2023-01-012023-06-300000776867us-gaap:TradeNamesMemberwtm:KuduInvestmentManagementLLCMember2023-06-300000776867us-gaap:TradeNamesMemberwtm:KuduInvestmentManagementLLCMember2022-12-310000776867us-gaap:CorporateAndOtherMemberus-gaap:TradeNamesMember2023-01-012023-06-300000776867us-gaap:CorporateAndOtherMemberus-gaap:TradeNamesMember2023-06-300000776867us-gaap:CorporateAndOtherMemberus-gaap:TradeNamesMember2022-12-310000776867us-gaap:CustomerRelationshipsMemberus-gaap:CorporateAndOtherMember2023-01-012023-06-300000776867us-gaap:CustomerRelationshipsMemberus-gaap:CorporateAndOtherMember2023-06-300000776867us-gaap:CustomerRelationshipsMemberus-gaap:CorporateAndOtherMember2022-12-310000776867us-gaap:CorporateAndOtherMemberus-gaap:OtherIntangibleAssetsMember2023-01-012023-06-300000776867us-gaap:CorporateAndOtherMemberus-gaap:OtherIntangibleAssetsMember2023-06-300000776867us-gaap:CorporateAndOtherMemberus-gaap:OtherIntangibleAssetsMember2022-12-310000776867us-gaap:OtherIntangibleAssetsMember2023-06-300000776867us-gaap:OtherIntangibleAssetsMember2022-12-310000776867us-gaap:GoodwillMember2023-03-310000776867us-gaap:OtherIntangibleAssetsMember2023-03-310000776867wtm:IntangibleAssetandGoodwillMember2023-03-310000776867us-gaap:GoodwillMember2022-03-310000776867us-gaap:OtherIntangibleAssetsMember2022-03-310000776867wtm:IntangibleAssetandGoodwillMember2022-03-310000776867us-gaap:GoodwillMember2023-04-012023-06-300000776867us-gaap:OtherIntangibleAssetsMember2023-04-012023-06-300000776867wtm:IntangibleAssetandGoodwillMember2023-04-012023-06-300000776867us-gaap:GoodwillMember2022-04-012022-06-300000776867us-gaap:OtherIntangibleAssetsMember2022-04-012022-06-300000776867wtm:IntangibleAssetandGoodwillMember2022-04-012022-06-300000776867us-gaap:GoodwillMember2023-06-300000776867us-gaap:OtherIntangibleAssetsMember2023-06-300000776867wtm:IntangibleAssetandGoodwillMember2023-06-300000776867us-gaap:GoodwillMember2022-06-300000776867us-gaap:OtherIntangibleAssetsMember2022-06-300000776867wtm:IntangibleAssetandGoodwillMember2022-06-300000776867us-gaap:GoodwillMember2022-12-310000776867us-gaap:OtherIntangibleAssetsMember2022-12-310000776867wtm:IntangibleAssetandGoodwillMember2022-12-310000776867us-gaap:GoodwillMember2021-12-310000776867us-gaap:OtherIntangibleAssetsMember2021-12-310000776867wtm:IntangibleAssetandGoodwillMember2021-12-310000776867us-gaap:GoodwillMember2023-01-012023-06-300000776867us-gaap:OtherIntangibleAssetsMember2023-01-012023-06-300000776867wtm:IntangibleAssetandGoodwillMember2023-01-012023-06-300000776867us-gaap:GoodwillMember2022-01-012022-06-300000776867us-gaap:OtherIntangibleAssetsMember2022-01-012022-06-300000776867wtm:IntangibleAssetandGoodwillMember2022-01-012022-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMember2023-03-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMember2022-03-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMember2021-12-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMember2022-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:TPCProvidersMember2023-03-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:TPCProvidersMember2022-03-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:TPCProvidersMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:TPCProvidersMember2021-12-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:TPCProvidersMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:TPCProvidersMember2022-06-300000776867wtm:ArkInsuranceHoldingsLimitedMemberwtm:TPCProvidersMember2020-12-310000776867wtm:ArkInsuranceHoldingsLimitedMemberwtm:TPCProvidersMember2021-12-310000776867wtm:ArkInsuranceHoldingsLimitedMemberwtm:TPCProvidersMember2019-12-310000776867wtm:ArkInsuranceHoldingsLimitedMember2023-04-012023-06-300000776867wtm:ArkInsuranceHoldingsLimitedMember2022-04-012022-06-300000776867wtm:ArkInsuranceHoldingsLimitedMember2023-01-012023-06-300000776867wtm:ArkInsuranceHoldingsLimitedMember2022-01-012022-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMember2023-04-012023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMember2023-01-012023-06-300000776867wtm:ArkInsuranceHoldingsLimitedMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMember2023-06-300000776867wtm:TPCProvidersMember2022-12-310000776867wtm:AllEntitiesExceptTPCProvidersMemberwtm:AMBestARatingOrBetterMember2023-06-300000776867wtm:AMBestAToARatingMemberwtm:AllEntitiesExceptTPCProvidersMember2023-06-300000776867wtm:AllEntitiesExceptTPCProvidersMemberwtm:AMBestBOrLowerAndNotRatedMember2023-06-300000776867wtm:AllEntitiesExceptTPCProvidersMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedMemberwtm:ThirdPointReMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedMemberwtm:ThirdPointReMember2022-12-310000776867us-gaap:SecuredDebtMemberwtm:HGSeniorNotesMember2023-06-300000776867wtm:HGSeniorNotesMember2023-06-300000776867us-gaap:SecuredDebtMemberwtm:HGSeniorNotesMember2022-12-310000776867wtm:HGSeniorNotesMember2022-12-310000776867wtm:ArkSubordinatedNotesMemberwtm:Ark2007NotesTranche1Member2023-06-300000776867wtm:ArkSubordinatedNotesMemberwtm:Ark2007NotesTranche1Member2022-12-310000776867wtm:Ark2021NotesTranche1Memberwtm:ArkSubordinatedNotesMember2023-06-300000776867wtm:Ark2021NotesTranche1Memberwtm:ArkSubordinatedNotesMember2022-12-310000776867wtm:Ark2021NotesTranche2Memberwtm:ArkSubordinatedNotesMember2023-06-300000776867wtm:Ark2021NotesTranche2Memberwtm:ArkSubordinatedNotesMember2022-12-310000776867wtm:Ark2021NotesTranche3Memberwtm:ArkSubordinatedNotesMember2023-06-300000776867wtm:Ark2021NotesTranche3Memberwtm:ArkSubordinatedNotesMember2022-12-310000776867wtm:ArkSubordinatedNotesMember2023-06-300000776867wtm:ArkSubordinatedNotesMember2022-12-310000776867wtm:Ark2021NotesMemberwtm:ArkSubordinatedNotesMember2023-06-300000776867wtm:Ark2021NotesMemberwtm:ArkSubordinatedNotesMember2022-12-310000776867wtm:ArkSubordinatedNotesMemberwtm:ArkInsuranceHoldingsLimitedMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedMember2023-06-300000776867wtm:ArkSubordinatedNotesMemberwtm:ArkInsuranceHoldingsLimitedMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedMember2022-12-310000776867wtm:KuduCreditFacilityMemberwtm:TermLoanMember2023-06-300000776867wtm:KuduCreditFacilityMemberwtm:TermLoanMember2022-12-310000776867wtm:KuduMemberwtm:KuduCreditFacilityMember2023-06-300000776867wtm:KuduMemberwtm:KuduCreditFacilityMember2022-12-310000776867wtm:OtherMemberwtm:TermLoanMember2023-06-300000776867wtm:OtherMemberwtm:TermLoanMember2022-12-310000776867wtm:OtherOperationsMemberwtm:OtherDebtMember2023-06-300000776867wtm:OtherOperationsMemberwtm:OtherDebtMember2022-12-310000776867us-gaap:SeniorNotesMemberus-gaap:SecuredDebtMember2022-04-292022-04-290000776867us-gaap:SeniorNotesMemberus-gaap:SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMemberus-gaap:SecuredDebtMember2022-04-292022-04-290000776867us-gaap:SeniorNotesMemberus-gaap:SecuredDebtMember2022-04-300000776867us-gaap:InterestRateCapMemberwtm:HgGlobalMember2022-06-160000776867us-gaap:SeniorNotesMemberus-gaap:SecuredDebtMember2022-06-160000776867us-gaap:SeniorNotesMemberus-gaap:SecuredDebtMember2023-01-012023-06-300000776867us-gaap:JuniorNotesMemberwtm:ArkInsuranceHoldingsLimitedMemberwtm:Ark2007NotesTranche1Member2007-03-310000776867us-gaap:JuniorNotesMemberwtm:UnitedStatesDollarLondonInterbankOfferedRateLIBORMemberwtm:ArkInsuranceHoldingsLimitedMemberwtm:Ark2007NotesTranche1Member2007-03-012007-03-310000776867us-gaap:JuniorNotesMemberwtm:ArkInsuranceHoldingsLimitedMemberwtm:Ark2007NotesTranche1Member2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedMemberwtm:UnsecuredSubordinatedDebtMemberwtm:GroupArkInsuranceLimitedMember2021-09-300000776867wtm:UnsecuredSubordinatedDebtMemberwtm:GroupArkInsuranceLimitedMember2021-07-012021-09-300000776867wtm:Ark2021NotesTranche1Memberwtm:UnsecuredSubordinatedDebtMemberwtm:GroupArkInsuranceLimitedMember2021-07-13iso4217:EUR0000776867wtm:Ark2021NotesTranche1Memberwtm:UnsecuredSubordinatedDebtMemberwtm:EURIBORMemberwtm:GroupArkInsuranceLimitedMember2021-07-012021-07-310000776867wtm:Ark2021NotesTranche2Memberwtm:UnsecuredSubordinatedDebtMemberwtm:GroupArkInsuranceLimitedMember2021-08-110000776867wtm:Ark2021NotesTranche2Memberwtm:UnsecuredSubordinatedDebtMemberwtm:GroupArkInsuranceLimitedMemberwtm:UnitedStatesDollarLondonInterbankOfferedRateLIBORMember2021-08-012021-08-310000776867wtm:Ark2021NotesTranche3Memberwtm:UnsecuredSubordinatedDebtMemberwtm:GroupArkInsuranceLimitedMember2021-09-080000776867wtm:Ark2021NotesTranche3Memberwtm:UnsecuredSubordinatedDebtMemberwtm:GroupArkInsuranceLimitedMemberwtm:UnitedStatesDollarLondonInterbankOfferedRateLIBORMember2021-09-082021-09-080000776867wtm:Ark2021NotesTranche3Memberwtm:UnsecuredSubordinatedDebtMemberwtm:GroupArkInsuranceLimitedMember2021-09-082021-09-080000776867wtm:Ark2021NotesTranche3Memberwtm:UnsecuredSubordinatedDebtMemberwtm:GroupArkInsuranceLimitedMember2021-09-012021-09-300000776867wtm:Ark2021NotesTranche1Member2023-06-300000776867us-gaap:UncollateralizedMemberwtm:ArkInsuranceHoldingsLimitedMemberus-gaap:LetterOfCreditMemberwtm:INGLOCFacilityMemberus-gaap:SecuredDebtMember2021-12-310000776867us-gaap:CollateralPledgedMemberwtm:ArkInsuranceHoldingsLimitedMemberus-gaap:LetterOfCreditMemberus-gaap:SecuredDebtMemberwtm:CitibankLOCFacilityMember2021-12-310000776867us-gaap:CollateralPledgedMemberwtm:ArkInsuranceHoldingsLimitedMemberus-gaap:LetterOfCreditMemberwtm:LloydsLOCFacilityMemberus-gaap:SecuredDebtMember2022-09-300000776867us-gaap:SecuredDebtMemberwtm:CitibankLOCFacilityMember2023-06-300000776867us-gaap:ShortTermInvestmentsMemberus-gaap:AssetPledgedAsCollateralMemberwtm:CitibankLOCFacilityMember2023-06-300000776867wtm:LloydsLOCFacilityMemberus-gaap:SecuredDebtMember2023-06-300000776867us-gaap:ShortTermInvestmentsMemberwtm:LloydsLOCFacilityMemberus-gaap:AssetPledgedAsCollateralMember2023-06-300000776867wtm:KuduMemberwtm:KuduBankFacilityMember2023-06-300000776867wtm:KuduBankFacilityMemberus-gaap:RevolvingCreditFacilityMember2023-06-300000776867wtm:KuduBankFacilityMemberwtm:LIBORMemberus-gaap:RevolvingCreditFacilityMember2023-01-012023-06-300000776867wtm:KuduBankFacilityMemberus-gaap:SubsequentEventMemberus-gaap:SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMemberus-gaap:RevolvingCreditFacilityMember2023-07-012023-07-010000776867wtm:KuduBankFacilityMemberus-gaap:SubsequentEventMemberus-gaap:RevolvingCreditFacilityMember2023-07-010000776867wtm:KuduMemberwtm:KuduBankFacilityMemberus-gaap:LineOfCreditMember2023-06-300000776867wtm:KuduMemberwtm:KuduBankFacilityMemberwtm:TermLoanMember2023-06-300000776867wtm:KuduMemberwtm:KuduCreditFacilityMemberwtm:TermLoanMember2023-03-310000776867wtm:KuduMemberwtm:KuduCreditFacilityMemberwtm:TermLoanMember2022-03-310000776867wtm:KuduMemberwtm:KuduCreditFacilityMemberwtm:TermLoanMember2022-12-310000776867wtm:KuduMemberwtm:KuduCreditFacilityMemberwtm:TermLoanMember2021-12-310000776867wtm:KuduMemberwtm:KuduCreditFacilityMemberwtm:TermLoanMember2023-04-012023-06-300000776867wtm:KuduMemberwtm:KuduCreditFacilityMemberwtm:TermLoanMember2022-04-012022-06-300000776867wtm:KuduMemberwtm:KuduCreditFacilityMemberwtm:TermLoanMember2023-01-012023-06-300000776867wtm:KuduMemberwtm:KuduCreditFacilityMemberwtm:TermLoanMember2022-01-012022-06-300000776867wtm:KuduMemberwtm:KuduCreditFacilityMemberwtm:TermLoanMember2023-06-300000776867wtm:KuduMemberwtm:KuduCreditFacilityMemberwtm:TermLoanMember2022-06-30wtm:credit_facility0000776867us-gaap:InterestRateCapMemberwtm:HgGlobalMember2022-06-162022-06-160000776867us-gaap:InterestRateCapMemberus-gaap:SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMemberwtm:HgGlobalMember2022-06-160000776867us-gaap:InterestRateCapMemberus-gaap:SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMemberwtm:HgGlobalMember2023-06-300000776867us-gaap:InterestExpenseMemberus-gaap:InterestRateCapMemberwtm:HgGlobalMember2023-04-012023-06-300000776867us-gaap:InterestExpenseMemberus-gaap:InterestRateCapMemberwtm:HgGlobalMember2023-01-012023-06-300000776867us-gaap:InterestExpenseMemberus-gaap:InterestRateCapMemberwtm:HgGlobalMember2022-04-012022-06-300000776867us-gaap:InterestExpenseMemberus-gaap:InterestRateCapMemberwtm:HgGlobalMember2022-01-012022-06-300000776867us-gaap:InterestRateCapMemberwtm:HgGlobalMember2023-04-012023-06-300000776867us-gaap:InterestRateCapMemberwtm:HgGlobalMember2023-01-012023-06-300000776867us-gaap:InterestRateCapMemberwtm:HgGlobalMember2023-06-300000776867us-gaap:InterestRateCapMemberwtm:HgGlobalMember2022-12-310000776867wtm:HgReMember2023-06-300000776867wtm:BamMemberwtm:FidusReLtd.Member2018-06-3000007768672018-01-012018-12-310000776867wtm:BamMemberwtm:FidusReLtd.Member2018-01-012018-12-310000776867wtm:BamMembersrt:MinimumMemberwtm:FidusReLtd.Member2018-01-012018-12-310000776867wtm:BamMemberwtm:FidusReLtd.Member2018-01-012018-12-310000776867srt:MaximumMemberwtm:BamMemberwtm:FidusReLtd.Member2018-01-012018-12-310000776867wtm:BamMemberwtm:A2018CoveredPortfolioMemberwtm:FidusReLtd.Member2023-01-012023-06-300000776867wtm:BamMemberwtm:FidusReLtd.Member2021-03-3100007768672021-01-012021-12-310000776867wtm:BamMemberwtm:FidusReLtd.Member2021-01-012021-12-310000776867wtm:BamMembersrt:MinimumMemberwtm:FidusReLtd.Member2021-01-012021-12-310000776867wtm:BamMemberwtm:FidusReLtd.Member2021-01-012021-12-310000776867srt:MaximumMemberwtm:BamMemberwtm:FidusReLtd.Member2021-01-012021-12-310000776867wtm:A2021CoveredPortfolioMemberwtm:BamMemberwtm:FidusReLtd.Member2023-01-012023-06-300000776867wtm:BamMemberwtm:FidusReLtd.Member2022-12-310000776867wtm:BamMemberwtm:FidusReLtd.Member2022-01-012022-12-310000776867wtm:BamMembersrt:MinimumMemberwtm:FidusReLtd.Member2022-01-012022-12-310000776867wtm:BamMemberwtm:FidusReLtd.Member2022-01-012022-12-310000776867srt:MaximumMemberwtm:BamMemberwtm:FidusReLtd.Member2022-01-012022-12-310000776867wtm:BamMemberwtm:FidusReLtd.Member2023-01-012023-06-300000776867srt:MaximumMemberwtm:BamMemberwtm:HgGlobalMember2023-01-012023-06-300000776867wtm:HgGlobalMember2023-01-012023-06-300000776867wtm:HgReMember2022-12-310000776867wtm:BAMSurplusNoteMemberwtm:HgGlobalMember2023-06-300000776867wtm:BAMSurplusNoteMemberwtm:HgGlobalMember2022-12-310000776867wtm:HgGlobalMember2023-06-300000776867wtm:HgGlobalMember2022-12-310000776867wtm:BamMember2023-06-300000776867wtm:BamMember2022-12-310000776867wtm:BamMemberus-gaap:UsTreasuryUstInterestRateMemberwtm:SurplusNoteMember2023-01-012023-06-300000776867wtm:BamMemberus-gaap:UsTreasuryUstInterestRateMembersrt:ScenarioForecastMemberwtm:SurplusNoteMember2023-12-310000776867wtm:BamMembersrt:ScenarioForecastMemberwtm:SurplusNoteMemberwtm:FixedinterestrateMember2025-01-010000776867wtm:BamMemberwtm:SurplusNoteMember2022-12-012022-12-310000776867wtm:BamMemberwtm:SupplementalTrustMember2022-12-012022-12-310000776867wtm:BamMemberwtm:SupplementalTrustMember2022-12-310000776867wtm:BamMemberwtm:SurplusNoteMember2022-12-310000776867wtm:BamMemberwtm:SurplusNoteMember2022-01-012022-06-300000776867wtm:BamMemberwtm:SurplusNoteMember2022-04-012022-06-300000776867wtm:BamMemberwtm:SurplusNoteMember2023-04-012023-06-300000776867wtm:BamMemberwtm:SurplusNoteMember2023-01-012023-06-300000776867wtm:BAMSurplusNoteMemberwtm:BamMember2023-06-300000776867wtm:BAMSurplusNoteMemberwtm:BamMember2022-12-310000776867wtm:BamMember2023-06-30wtm:Contract0000776867wtm:BamMember2022-12-310000776867wtm:BamMember2023-01-012023-06-300000776867wtm:BamMember2022-01-012022-12-310000776867wtm:HGBAMMember2023-04-012023-06-300000776867wtm:HGBAMMember2022-04-012022-06-300000776867wtm:HGBAMMember2023-01-012023-06-300000776867wtm:HGBAMMember2022-01-012022-06-300000776867wtm:WTMIncentivePlanMemberus-gaap:PerformanceSharesMember2023-01-012023-06-300000776867wtm:WTMIncentivePlanMembersrt:MinimumMemberus-gaap:PerformanceSharesMember2023-01-012023-06-300000776867wtm:WTMIncentivePlanMembersrt:MaximumMemberus-gaap:PerformanceSharesMember2023-01-012023-06-300000776867wtm:WTMIncentivePlanMemberus-gaap:PerformanceSharesMember2023-03-310000776867wtm:WTMIncentivePlanMemberus-gaap:PerformanceSharesMember2022-03-310000776867wtm:WTMIncentivePlanMemberus-gaap:PerformanceSharesMember2022-12-310000776867wtm:WTMIncentivePlanMemberus-gaap:PerformanceSharesMember2021-12-310000776867wtm:WTMIncentivePlanMemberus-gaap:PerformanceSharesMember2023-04-012023-06-300000776867wtm:WTMIncentivePlanMemberus-gaap:PerformanceSharesMember2022-04-012022-06-300000776867wtm:WTMIncentivePlanMemberus-gaap:PerformanceSharesMember2022-01-012022-06-300000776867wtm:WTMIncentivePlanMemberus-gaap:PerformanceSharesMember2023-06-300000776867wtm:WTMIncentivePlanMemberus-gaap:PerformanceSharesMember2022-06-300000776867wtm:WTMIncentivePlanMemberwtm:RangeOfPerformanceCycleCurrentYearMemberus-gaap:PerformanceSharesMember2023-03-012023-03-310000776867wtm:WTMIncentivePlanMemberwtm:RangeOfPerformanceCyclePreviousYearMemberus-gaap:PerformanceSharesMember2022-03-012022-03-310000776867wtm:WTMIncentivePlanMemberus-gaap:PerformanceSharesMember2019-01-012021-12-310000776867wtm:WTMIncentivePlanMemberwtm:RangeOfPerformanceCyclePreviousYearMemberus-gaap:PerformanceSharesMember2023-06-300000776867wtm:PerformanceCyclePeriodTwoMemberwtm:WTMIncentivePlanMemberus-gaap:PerformanceSharesMember2023-06-300000776867wtm:WTMIncentivePlanMemberus-gaap:PerformanceSharesMemberwtm:PerformanceCyclePeriodThreeMember2023-06-300000776867us-gaap:RestrictedStockMember2023-01-012023-06-300000776867wtm:WTMIncentivePlanMemberus-gaap:RestrictedStockMember2023-03-310000776867wtm:WTMIncentivePlanMemberus-gaap:RestrictedStockMember2022-03-310000776867wtm:WTMIncentivePlanMemberus-gaap:RestrictedStockMember2022-12-310000776867wtm:WTMIncentivePlanMemberus-gaap:RestrictedStockMember2021-12-310000776867wtm:WTMIncentivePlanMemberus-gaap:RestrictedStockMember2023-04-012023-06-300000776867wtm:WTMIncentivePlanMemberus-gaap:RestrictedStockMember2022-04-012022-06-300000776867wtm:WTMIncentivePlanMemberus-gaap:RestrictedStockMember2023-01-012023-06-300000776867wtm:WTMIncentivePlanMemberus-gaap:RestrictedStockMember2022-01-012022-06-300000776867wtm:WTMIncentivePlanMemberus-gaap:RestrictedStockMember2023-06-300000776867wtm:WTMIncentivePlanMemberus-gaap:RestrictedStockMember2022-06-300000776867wtm:HgGlobalMember2023-06-300000776867wtm:HgGlobalMember2022-12-310000776867wtm:ArkInsuranceHoldingsLimitedMember2023-06-300000776867wtm:ArkInsuranceHoldingsLimitedMember2022-12-310000776867wtm:KuduInvestmentManagementLLCMember2023-06-300000776867wtm:KuduInvestmentManagementLLCMember2022-12-310000776867wtm:OtherOperationsMember2023-06-300000776867wtm:OtherOperationsMember2022-12-310000776867wtm:TotalNonControllingExcludingReciprocalsMember2023-06-300000776867wtm:TotalNonControllingExcludingReciprocalsMember2022-12-310000776867wtm:BuildAmericaMutualMember2023-06-300000776867wtm:BuildAmericaMutualMember2022-12-310000776867wtm:HgGlobalMemberwtm:HgGlobalBamMember2023-04-012023-06-300000776867wtm:BamMemberwtm:HgGlobalBamMember2023-04-012023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:ArkInsuranceHoldingsLimitedMember2023-04-012023-06-300000776867wtm:OutriggerReMemberwtm:ArkInsuranceHoldingsLimitedOutriggerMember2023-04-012023-06-300000776867wtm:HgGlobalMemberwtm:HgGlobalBamMember2022-04-012022-06-300000776867wtm:BamMemberwtm:HgGlobalBamMember2022-04-012022-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:ArkInsuranceHoldingsLimitedMember2022-04-012022-06-300000776867wtm:HgGlobalMemberwtm:HgGlobalBamMember2023-01-012023-06-300000776867wtm:BamMemberwtm:HgGlobalBamMember2023-01-012023-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:ArkInsuranceHoldingsLimitedMember2023-01-012023-06-300000776867wtm:OutriggerReMemberwtm:ArkInsuranceHoldingsLimitedOutriggerMember2023-01-012023-06-300000776867wtm:HgGlobalMemberwtm:HgGlobalBamMember2022-01-012022-06-300000776867wtm:BamMemberwtm:HgGlobalBamMember2022-01-012022-06-300000776867wtm:ArkInsuranceHoldingsLimitedOutriggerMemberwtm:ArkInsuranceHoldingsLimitedMember2022-01-012022-06-300000776867wtm:DavidShieldMember2023-06-300000776867wtm:DavidShieldPassportCardMember2023-06-300000776867wtm:ElementumHoldingsL.P.Member2023-06-300000776867wtm:LimitedPartnershipsMember2023-06-300000776867wtm:KuduInvestmentsMembersrt:MinimumMember2023-06-300000776867srt:MaximumMemberwtm:KuduInvestmentsMember2023-06-300000776867wtm:KuduInvestmentsMember2023-06-300000776867wtm:KuduInvestmentsMembersrt:MinimumMember2022-12-310000776867srt:MaximumMemberwtm:KuduInvestmentsMember2022-12-310000776867wtm:KuduInvestmentsMember2022-12-310000776867wtm:MediaAlphaMember2022-12-310000776867wtm:DavidShieldPassportCardMember2022-12-310000776867wtm:ElementumHoldingsL.P.Member2022-12-310000776867wtm:OtherInvestmentSectorMember2023-06-300000776867wtm:OtherInvestmentSectorMember2022-12-310000776867us-gaap:EquityMethodInvestmentsMember2023-06-300000776867us-gaap:EquityMethodInvestmentsMember2022-12-310000776867us-gaap:EquityMethodInvesteeMember2023-04-012023-06-300000776867us-gaap:EquityMethodInvesteeMember2023-01-012023-06-300000776867us-gaap:EquityMethodInvesteeMember2022-04-012022-06-300000776867us-gaap:EquityMethodInvesteeMember2022-01-012022-06-300000776867wtm:MediaAlphaMember2023-06-300000776867wtm:MediaAlphaMember2022-12-310000776867wtm:MediaAlphaMember2023-04-012023-06-300000776867wtm:MediaAlphaMember2022-04-012022-06-300000776867wtm:MediaAlphaMember2023-01-012023-06-300000776867wtm:MediaAlphaMember2022-01-012022-06-300000776867us-gaap:EstimateOfFairValueFairValueDisclosureMemberus-gaap:SeniorNotesMember2023-06-300000776867us-gaap:SeniorNotesMemberus-gaap:CarryingReportedAmountFairValueDisclosureMember2023-06-300000776867us-gaap:EstimateOfFairValueFairValueDisclosureMemberus-gaap:SeniorNotesMember2022-12-310000776867us-gaap:SeniorNotesMemberus-gaap:CarryingReportedAmountFairValueDisclosureMember2022-12-310000776867us-gaap:EstimateOfFairValueFairValueDisclosureMemberwtm:Ark2007NotesMember2023-06-300000776867wtm:Ark2007NotesMemberus-gaap:CarryingReportedAmountFairValueDisclosureMember2023-06-300000776867us-gaap:EstimateOfFairValueFairValueDisclosureMemberwtm:Ark2007NotesMember2022-12-310000776867wtm:Ark2007NotesMemberus-gaap:CarryingReportedAmountFairValueDisclosureMember2022-12-310000776867wtm:Ark2021NotesMemberus-gaap:EstimateOfFairValueFairValueDisclosureMember2023-06-300000776867wtm:Ark2021NotesMemberus-gaap:CarryingReportedAmountFairValueDisclosureMember2023-06-300000776867wtm:Ark2021NotesMemberus-gaap:EstimateOfFairValueFairValueDisclosureMember2022-12-310000776867wtm:Ark2021NotesMemberus-gaap:CarryingReportedAmountFairValueDisclosureMember2022-12-310000776867wtm:KuduCreditFacilityMemberus-gaap:EstimateOfFairValueFairValueDisclosureMember2023-06-300000776867wtm:KuduCreditFacilityMemberus-gaap:CarryingReportedAmountFairValueDisclosureMember2023-06-300000776867wtm:KuduCreditFacilityMemberus-gaap:EstimateOfFairValueFairValueDisclosureMember2022-12-310000776867wtm:KuduCreditFacilityMemberus-gaap:CarryingReportedAmountFairValueDisclosureMember2022-12-310000776867wtm:OtherOperationsMemberus-gaap:EstimateOfFairValueFairValueDisclosureMember2023-06-300000776867wtm:OtherOperationsMemberus-gaap:CarryingReportedAmountFairValueDisclosureMember2023-06-300000776867wtm:OtherOperationsMemberus-gaap:EstimateOfFairValueFairValueDisclosureMember2022-12-310000776867wtm:OtherOperationsMemberus-gaap:CarryingReportedAmountFairValueDisclosureMember2022-12-310000776867wtm:NSMInsuranceGroupMemberus-gaap:DiscontinuedOperationsHeldforsaleMember2022-04-012022-06-300000776867wtm:NSMInsuranceGroupMemberus-gaap:DiscontinuedOperationsHeldforsaleMember2022-01-012022-06-300000776867us-gaap:SegmentDiscontinuedOperationsMember2022-04-012022-06-300000776867us-gaap:SegmentDiscontinuedOperationsMember2022-01-012022-06-30

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
 
FORM 10-Q
    QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
 
For the period ended June 30, 2023
 
OR
 
         TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
 
For the transition period from          to         
Commission file number 1-8993

WHITE MOUNTAINS INSURANCE GROUP, LTD.
(Exact name of Registrant as specified in its charter)
Bermuda 
(State or other jurisdiction of incorporation or organization) 94-2708455
23 South Main Street, Suite 3B (I.R.S. Employer Identification No.)
Hanover, 03755-2053
New Hampshire(Zip Code)
(Address of principal executive offices) 
 
Registrant’s telephone number, including area code: (603640-2200
 Securities registered pursuant to Section 12(b) of the Act:
Title of each classTrading Symbol(s)Name of each exchange on which registered
Common Shares, par value $1.00 per shareWTMNew York Stock Exchange
WTM.BHBermuda Stock Exchange
Indicate by check mark whether the Registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes   ý   No   
 
Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was required to submit such files). Yes   ý    No   
 
Indicate by check mark whether the Registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company.  See the definitions of “large accelerated filer,” “accelerated filer”, “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.
Large accelerated filerýAccelerated filerNon-accelerated filer
Smaller reporting companyEmerging growth company

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  o
 
Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes     No  ý

As of August 3, 2023, 2,560,452 common shares with a par value of $1.00 per share were outstanding (which includes 37,595 restricted common shares that were not vested at such date).




WHITE MOUNTAINS INSURANCE GROUP, LTD.

Table of Contents
 
  Page No.
   
 
   
 
   
 
Consolidated Balance Sheets, June 30, 2023 and December 31, 2022
  
 
 
     Three and Six Months Ended June 30, 2023 and 2022
 
 
     Three and Six Months Ended June 30, 2023 and 2022
 
Consolidated Statements of Cash Flows, Six Months Ended June 30, 2023 and 2022
  
 
  
  
 
Results of Operations for the Three and Six Months Ended June 30, 2023 and 2022
  
 
  
 
 
  
 
  
  
  
  
  





Part I.FINANCIAL INFORMATION.
Item 1.Financial Statements
WHITE MOUNTAINS INSURANCE GROUP, LTD.
CONSOLIDATED BALANCE SHEETS
(Unaudited)
June 30, 2023December 31, 2022
Millions, except share and per share amounts
Assets
Financial Guarantee (HG Global/BAM)
Fixed maturity investments, at fair value$932.9 $909.9 
Short-term investments, at fair value67.5 65.9 
Total investments1,000.4 975.8 
Cash2.9 18.2 
Insurance premiums receivable6.4 6.6 
Deferred acquisition costs37.4 36.0 
Other assets25.3 21.9 
Total Financial Guarantee assets1,072.4 1,058.5 
P&C Insurance and Reinsurance (Ark/WM Outrigger)
Fixed maturity investments, at fair value755.8 772.8 
Common equity securities, at fair value382.6 334.6 
Short-term investments, at fair value640.3 484.6 
Other long-term investments410.7 373.6 
Total investments2,189.4 1,965.6 
Cash101.7 101.5 
Reinsurance recoverables669.7 595.3 
Insurance premiums receivable1,077.2 544.1 
Deferred acquisition costs232.1 127.2 
Goodwill and other intangible assets292.5 292.5 
Other assets69.4 65.2 
Total P&C Insurance and Reinsurance assets4,632.0 3,691.4 
Asset Management (Kudu)
     Short-term investments, at fair value4.1  
     Other long-term investments737.1 695.9 
Total investments741.2 695.9 
     Cash (restricted $13.4 and $12.2)
25.0 101.4 
     Accrued investment income13.1 12.4 
     Goodwill and other intangible assets8.4 8.6 
     Other assets10.0 7.6 
Total Asset Management assets797.7 825.9 
Other Operations
     Fixed maturity investments, at fair value252.0 238.2 
     Common equity securities, at fair value272.5 333.8 
Investment in MediaAlpha, at fair value235.7 168.6 
     Short-term investments, at fair value274.2 373.6 
     Other long-term investments667.2 418.5 
     Total investments1,701.6 1,532.7 
     Cash24.9 33.9 
     Goodwill and other intangible assets72.7 91.3 
     Other assets75.0 155.6 
     Total Other Operations assets1,874.2 1,813.5 
Total assets$8,376.3 $7,389.3 
See Notes to Consolidated Financial Statements
1





CONSOLIDATED BALANCE SHEETS (CONTINUED)
(Unaudited)
June 30, 2023December 31, 2022
Millions, except share and per share amounts
Liabilities
Financial Guarantee (HG Global/BAM)
Unearned insurance premiums$303.7 $298.3 
Debt146.7 146.5 
Accrued incentive compensation14.7 28.0 
Other liabilities34.6 29.0 
Total Financial Guarantee liabilities499.7 501.8 
P&C Insurance and Reinsurance (Ark/WM Outrigger)
Loss and loss adjustment expense reserves1,421.0 1,296.5 
Unearned insurance premiums1,376.5 623.2 
Debt185.1 183.7 
Reinsurance payable247.0 251.1 
Contingent consideration45.1 45.3 
Other liabilities116.6 122.3 
Total P&C Insurance and Reinsurance liabilities3,391.3 2,522.1 
Asset Management (Kudu)
Debt203.7 208.3 
     Other liabilities51.0 65.0 
     Total Asset Management liabilities254.7 273.3 
Other Operations
Debt30.6 36.7 
Accrued incentive compensation51.0 86.1 
Other liabilities23.1 34.3 
Total Other Operations liabilities104.7 157.1 
Total liabilities4,250.4 3,454.3 
Equity
White Mountains’s common shareholders’ equity
White Mountains’s common shares at $1 par value per share—authorized 50,000,000
   shares; issued and outstanding 2,560,452 and 2,572,156 shares
2.6 2.6 
Paid-in surplus540.6536.0
Retained earnings3,380.7 3,211.8 
Accumulated other comprehensive income (loss), after-tax:
Net unrealized gains (losses) from foreign currency translation and
    interest rate swap
(1.7)(3.5)
Total White Mountains’s common shareholders’ equity3,922.2 3,746.9 
Noncontrolling interests203.7 188.1 
Total equity4,125.9 3,935.0 
Total liabilities and equity$8,376.3 $7,389.3 
See Notes to Consolidated Financial Statements
2


WHITE MOUNTAINS INSURANCE GROUP, LTD.
CONSOLIDATED STATEMENTS OF OPERATIONS
(Unaudited)

Three Months Ended June 30,Six Months Ended June 30,
Millions2023202220232022
Revenues:
Financial Guarantee (HG Global/BAM)
Earned insurance premiums$7.7 $10.5 $15.4 $18.9 
Net investment income7.6 4.8 14.8 9.4 
Net realized and unrealized investment gains (losses)(9.9)(30.1)7.1 (75.2)
Other revenues.5 1.6 1.3 2.4 
Total Financial Guarantee revenues5.9 (13.2)38.6 (44.5)
P&C Insurance and Reinsurance (Ark/WM Outrigger)
Earned insurance premiums293.3 217.3 548.4 411.7 
Net investment income13.7 3.2 24.3 4.8 
Net realized and unrealized investment gains (losses)18.0 (44.6)42.5 (62.1)
Other revenues(2.0)6.3 (4.7)3.5 
Total P&C Insurance and Reinsurance revenues323.0 182.2 610.5 357.9 
Asset Management (Kudu)
Net investment income14.7 13.8 28.9 26.4 
Net realized and unrealized investment gains (losses)4.6 (17.6)34.2 4.7 
Total Asset Management revenues19.3 (3.8)63.1 31.1 
Other Operations
   Net investment income7.0 3.3 14.0 5.1 
   Net realized and unrealized investment gains (losses)76.0 (11.8)117.8 20.1 
   Net realized and unrealized investment gains (losses) from
      investment in MediaAlpha
(77.3)(113.5)7.9 (94.7)
   Commission revenues3.2 2.6 6.5 5.5 
   Other revenues21.3 30.9 51.9 56.6 
Total Other Operations revenues30.2 (88.5)198.1 (7.4)
Total revenues$378.4 $76.7 $910.3 $337.1 
See Notes to Consolidated Financial Statements
3


CONSOLIDATED STATEMENTS OF OPERATIONS (CONTINUED)
(Unaudited)

Three Months Ended June 30,Six Months Ended June 30,
Millions2023202220232022
Expenses:
Financial Guarantee (HG Global/BAM)
Acquisition expenses$1.5 $4.8 $4.2 $7.8 
General and administrative expenses14.9 17.4 32.2 33.7 
Interest expense2.5 3.4 7.0 3.4 
Total Financial Guarantee expenses18.9 25.6 43.4 44.9 
P&C Insurance and Reinsurance (Ark/WM Outrigger)
Loss and loss adjustment expenses167.5 120.5 315.3 242.5 
Acquisition expenses61.4 50.2 121.2 100.1 
General and administrative expenses34.9 29.7 70.1 50.7 
Change in fair value of contingent consideration2.2 .1(.2)2.2 
Interest expense5.2 3.1 10.2 6.9 
Total P&C Insurance and Reinsurance expenses271.2 203.6 516.6 402.4 
Asset Management (Kudu)
General and administrative expenses4.0 3.1 7.8 5.9 
Interest expense5.3 3.3 10.0 6.1 
Total Asset Management expenses9.3 6.4 17.8 12.0 
Other Operations
   Cost of sales11.6 22.4 25.5 43.8 
   General and administrative expenses48.8 51.0 88.5 80.8 
   Interest expense1.2 .3 2.0 .6 
Total Other Operations expenses61.6 73.7 116.0 125.2 
Total expenses361.0 309.3 693.8 584.5 
Pre-tax income (loss) from continuing operations17.4 (232.6)216.5 (247.4)
   Income tax (expense) benefit(.2)16.0 (12.1)18.7 
Net income (loss) from continuing operations17.2 (216.6)204.4 (228.7)
Net income (loss) from discontinued operations, net of tax - NSM Group 6.4  10.1 
Net income (loss)17.2 (210.2)204.4 (218.6)
   Net (income) loss attributable to noncontrolling interests2.4 41.0 (5.3)82.8 
Net income (loss) attributable to White Mountains’s
   common shareholders
$19.6 $(169.2)$199.1 $(135.8)
See Notes to Consolidated Financial Statements
4


WHITE MOUNTAINS INSURANCE GROUP, LTD.
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
(Unaudited)

Three Months Ended June 30,Six Months Ended June 30,
Millions2023202220232022
Net income (loss) attributable to White Mountains’s
   common shareholders
$19.6 $(169.2)$199.1 $(135.8)
Other comprehensive income, net of tax:
Other comprehensive income (loss), net of tax1.4 (1.1)2.6 (1.5)
Other comprehensive income (loss) from discontinued operations,
   net of tax - NSM Group
 (4.0) (5.9)
Comprehensive income (loss) 21.0 (174.3)201.7 (143.2)
Other comprehensive (income) loss attributable to
   noncontrolling interests
(.4).5 (.8).7 
Comprehensive income (loss) attributable to
   White Mountains’s common shareholders
$20.6 $(173.8)$200.9 $(142.5)

Earnings (loss) per share attributable to White Mountains’s common shareholders:
Basic earnings (loss) per share
Continuing operations$7.65 $(58.78)$77.57 $(48.57)
Discontinued operations 1.98  3.17 
Total consolidated operations$7.65 $(56.80)$77.57 $(45.40)
Diluted earnings (loss) per share
Continuing operations$7.65 $(58.78)$77.57 $(48.57)
Discontinued operations 1.98  3.17 
Total consolidated operations$7.65 $(56.80)$77.57 $(45.40)
Dividends declared and paid per White Mountains’s
   common share
$ $ $1.00 $1.00 
See Notes to Consolidated Financial Statements.

5


WHITE MOUNTAINS INSURANCE GROUP, LTD.
CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY
(Unaudited)

 White Mountains’s Common Shareholders’ Equity 
MillionsCommon shares and paid-in surplusRetained earningsAOCI, after taxTotalNon-controlling interestTotal Equity
Balance at March 31, 2023$537.8 $3,367.3 $(2.7)$3,902.4 $190.4 $4,092.8 
Net income (loss) 19.6  19.6 (2.4)17.2 
Other comprehensive income (loss), net of tax  1.0 1.0 .4 1.4 
Total comprehensive income (loss) 19.6 1.0 20.6 (2.0)18.6 
Dividends to noncontrolling interests    (.6)(.6)
Issuances of common shares2.0   2.0  2.0 
Repurchases and retirements of common shares(1.2)(6.2) (7.4) (7.4)
BAM member surplus contribution, net of tax    14.7 14.7 
Amortization of restricted share awards4.1   4.1  4.1 
Recognition of equity-based compensation expense
   of subsidiaries
.5   .5 .1 .6 
Net contributions and dilution from other
   noncontrolling interests
    1.1 1.1 
Balance at June 30, 2023$543.2 $3,380.7 $(1.7)$3,922.2 $203.7 $4,125.9 

 White Mountains’s Common Shareholders’ Equity 
MillionsCommon shares and paid-in surplusRetained earningsAOCI, after taxTotalNon-controlling interestTotal Equity
Balance at March 31, 2022$586.3 $2,956.2 $(.4)$3,542.1 $127.2 $3,669.3 
Net income (loss)— (169.2)— (169.2)(41.0)(210.2)
Other comprehensive income (loss), net of tax— — (.6)(.6)(.5)(1.1)
Net gain (loss) from foreign currency translation
   from sale of discontinued operations, net of tax -
   NSM Group
— — (4.0)(4.0)— (4.0)
Total comprehensive income (loss)— (169.2)(4.6)(173.8)(41.5)(215.3)
Dividends to noncontrolling interests— — — — (6.4)(6.4)
Issuances of common shares2.2 — — 2.2 — 2.2 
Issuance of shares of non-controlling interests— — — — 74.6 74.6 
Repurchases and retirements of common shares(10.4)(52.2)— (62.6)— (62.6)
BAM member surplus contributions, net of tax— — — — 24.0 24.0 
Amortization of restricted share awards3.6 — — 3.6 — 3.6 
Recognition of equity-based compensation expense
   of subsidiaries
6.5 — — 6.5 .4 6.9 
Net contributions and dilution from other
   noncontrolling interests
15.0 (9.7)— 5.3 (9.6)(4.3)
Balance at June 30, 2022$603.2 $2,725.1 $(5.0)$3,323.3 $168.7 $3,492.0 
See Notes to Consolidated Financial Statements.
6


CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (CONTINUED)
(Unaudited)

 White Mountains’s Common Shareholders’ Equity 
MillionsCommon shares and paid-in surplusRetained earningsAOCI, after taxTotalNon-controlling interestTotal Equity
Balance at January 1, 2023$538.6 $3,211.8 $(3.5)$3,746.9 $188.1 $3,935.0 
Net income (loss) 199.1  199.1 5.3 204.4 
Other comprehensive income (loss), net of tax  1.8 1.8 .8 2.6 
Total comprehensive income (loss)