<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2013-05-10</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000860730</issuerCik>
        <issuerName>HCA Holdings, Inc.</issuerName>
        <issuerTradingSymbol>HCA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001392780</rptOwnerCik>
            <rptOwnerName>HERCULES HOLDING II, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O HCA HOLDINGS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>ONE PARK PLAZA</rptOwnerStreet2>
            <rptOwnerCity>NASHVILLE</rptOwnerCity>
            <rptOwnerState>TN</rptOwnerState>
            <rptOwnerZipCode>37203</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.01 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2013-05-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4700233</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>169574819</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">This transaction represents a distribution for no consideration by Hercules Holding II, LLC of 4,700,233 shares of HCA Holdings, Inc.'s common stock, par value $.01 per share (&quot;Common Stock&quot;), to certain members of Hercules Holding II, LLC, which shares had previously been indirectly beneficially owned by such members through their direct ownership in Hercules Holding II, LLC.</footnote>
        <footnote id="F2">Following the distribution of shares of Common Stock reported herein, Hercules directly holds 169,574,819 shares of Common Stock.  The membership interests of Hercules Holding II, LLC are held by a private investor group, including affiliates of Bain Capital Partners, LLC, Kohlberg Kravis Roberts &amp; Co. L.P. and Company founder Dr. Thomas F. Frist, Jr.  Each of such persons disclaims membership in any such group and each of such persons other than Hercules Holding II, LLC disclaims beneficial ownership of these securities, except to the extent of its pecuniary interest therein.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ John M. Franck II, by power of attorney for Hercules Holding II, LLC</signatureName>
        <signatureDate>2013-05-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
