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  <xsd:element id="ob_ProceedsFromMaturitiesOfTradingSecuritiesDebt" name="ProceedsFromMaturitiesOfTradingSecuritiesDebt" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
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  <xsd:element abstract="true" id="ob_SecuritiesIssuedin2014Member" name="SecuritiesIssuedin2014Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
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  <xsd:element abstract="true" id="ob_ShareBasedCompensationArrangementByPerformanceSharesAwardPerformanceCycleDomain" name="ShareBasedCompensationArrangementByPerformanceSharesAwardPerformanceCycleDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ob_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalCostToBeRecognizedIfPerformanceSharesVested" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalCostToBeRecognizedIfPerformanceSharesVested" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="ob_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAmountsPaidInPeriod" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAmountsPaidInPeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="ob_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAssumedForfeituresInPeriod" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAssumedForfeituresInPeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="instant" />
  <xsd:element id="ob_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumberBeforeForfeitures" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumberBeforeForfeitures" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="instant" />
  <xsd:element id="ob_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTargetSharesPaidInPeriod" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTargetSharesPaidInPeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="ob_ShareBasedCompensationArrangementbyShareBasedPaymentAwardEquityInstrumentsOtherthanOptionsAssumedForfeituresPayable" name="ShareBasedCompensationArrangementbyShareBasedPaymentAwardEquityInstrumentsOtherthanOptionsAssumedForfeituresPayable" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ob_SharebasedCompensationArrangementbySharebasedPaymentAwardPayoutforMinimumGrowthTargetPercentage" name="SharebasedCompensationArrangementbySharebasedPaymentAwardPayoutforMinimumGrowthTargetPercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ob_SingleFundMember" name="SingleFundMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ob_SpecialtyIndustriesMember" name="SpecialtyIndustriesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ob_SpecialtyProductsMember" name="SpecialtyProductsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ob_StandardPoorsNRRatingMember" name="StandardPoorsNRRatingMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ob_SubordinateMember" name="SubordinateMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ob_SuperSeniorMember" name="SuperSeniorMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ob_SurplusNotesForSaleOfDiscontinuedOperationsMember" name="SurplusNotesForSaleOfDiscontinuedOperationsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ob_SurplusNotesIssuedAsSellerFinancingInSaleOfDiscontinuedOperations" name="SurplusNotesIssuedAsSellerFinancingInSaleOfDiscontinuedOperations" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ob_TaxAssessmentYear2007To2009Member" name="TaxAssessmentYear2007To2009Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ob_TaxAssessmentYearAxis" name="TaxAssessmentYearAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ob_TaxAssessmentYearDomain" name="TaxAssessmentYearDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ob_TaxDevelopmentFundMember" name="TaxDevelopmentFundMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ob_TaxYear2005to2006Member" name="TaxYear2005to2006Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ob_TechnologyMember" name="TechnologyMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ob_TokioMarineAndNichidoFireMember" name="TokioMarineAndNichidoFireMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ob_TradingSecuritiesAndCertainTradingAssetsFixedMaturityInvestmentsTableTextBlock" name="TradingSecuritiesAndCertainTradingAssetsFixedMaturityInvestmentsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="ob_TradingSecuritiesConvertibleFixedMaturityInvestments" name="TradingSecuritiesConvertibleFixedMaturityInvestments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="ob_TradingSecuritiesGrossUnrealizedGain" name="TradingSecuritiesGrossUnrealizedGain" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="ob_TradingSecuritiesGrossUnrealizedGainLossTableTextBlock" name="TradingSecuritiesGrossUnrealizedGainLossTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="ob_TradingSecuritiesGrossUnrealizedLoss" name="TradingSecuritiesGrossUnrealizedLoss" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ob_TradingSecuritiesNetUnrealizedForeignCurrencyGainLoss" name="TradingSecuritiesNetUnrealizedForeignCurrencyGainLoss" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ob_TribuneCompanyLitigationMember" name="TribuneCompanyLitigationMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ob_TrustCertificatesIssuedUponDissolutionofaPrivateEquityFundMember" name="TrustCertificatesIssuedUponDissolutionofaPrivateEquityFundMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ob_UnrealizedGainLossOnInvestmentsUnobservableInputsTableTextBlock" name="UnrealizedGainLossOnInvestmentsUnobservableInputsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="ob_Unrealizedgainslossesontradingsecuritiesnetoftax" name="Unrealizedgainslossesontradingsecuritiesnetoftax" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="ob_UnrestrictedCollateralFromCustomers" name="UnrestrictedCollateralFromCustomers" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ob_UtilitiesMember" name="UtilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ob_WhiteMountainsInsuranceGroupLtdMember" name="WhiteMountainsInsuranceGroupLtdMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
</xsd:schema>


