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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-01-01</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000878520</issuerCik>
        <issuerName>Hilltop Securities Holdings LLC</issuerName>
        <issuerTradingSymbol>SWS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001304696</rptOwnerCik>
            <rptOwnerName>Moses Michael A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1201 ELM STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 3500</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75270</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock $.10 Par Value</value>
            </securityTitle>
            <transactionDate>
                <value>2015-01-01</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>38748</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">As of the effective time (the &quot;Effective Time&quot;) of the transactions contemplated by the Agreement and Plan of Merger by and among the Issuer, Hilltop Holdings Inc. (&quot;Hilltop&quot;), and Peruna LLC, dated as of March 31, 2014 (the &quot;Merger Agreement&quot;), pursuant to the terms of the Merger Agreement, each share of the Issuer's common stock held by the reporting person that was outstanding as of immediately prior to the Effective Time was converted into the right to receive (a) 0.2496 shares of Hilltop common stock and (b) $1.94 in cash, without interest.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Allen R. Tubb, Power of Attorney</signatureName>
        <signatureDate>2015-01-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
