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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2020-05-21</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001592386</issuerCik>
        <issuerName>Virtu Financial, Inc.</issuerName>
        <issuerTradingSymbol>VIRT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001602512</rptOwnerCik>
            <rptOwnerName>TJMT Holdings LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O VIRTU FINANCIAL, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>165 BROADWAY</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10006</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>See Remarks</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001573310</rptOwnerCik>
            <rptOwnerName>Viola Michael T</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O VIRTU FINANCIAL, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>165 BROADWAY</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10006</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001602918</rptOwnerCik>
            <rptOwnerName>Viola Teresa</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O VIRTU FINANCIAL, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>165 BROADWAY</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10006</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>See Remarks</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001573350</rptOwnerCik>
            <rptOwnerName>Viola Vincent J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O VIRTU FINANCIAL, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>165 BROADWAY</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10006</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class C common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-05-22</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>216680</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>216680</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F7"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class D common stock</value>
                <footnoteId id="F2"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>60091740</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F7"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Warrant</value>
                <footnoteId id="F3"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>22.98</value>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2020-05-21</value>
                <footnoteId id="F4"/>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3000000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2020-05-22</value>
            </exerciseDate>
            <expirationDate>
                <value>2022-01-15</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A common stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3000000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3000000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F7"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Non-voting common interest units of Virtu Financial LLC</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
                <footnoteId id="F5"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2020-05-22</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>216680</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F5"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A common stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>216680</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>216680</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F7"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeHolding>
            <securityTitle>
                <value>Non-voting common interest units of Virtu Financial LLC</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F6"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F6"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A common stock and Class B common stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>60091740</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>60091740</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F7"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">TJMT Holdings LLC acquired 216,680 non-voting common interest units of Virtu Financial LLC (&quot;Virtu Financial Units&quot;) and an equal number of shares of Class C common stock of the Issuer (&quot;Class C Common Stock&quot;) for a per share purchase price of $26.00.</footnote>
        <footnote id="F2">Shares of Class D common stock of the Issuer (&quot;Class D Common Stock&quot;) have 10 votes per share but no economic rights (including rights to dividends and distributions upon liquidation) and are paired with an equal number of Virtu Financial Units.</footnote>
        <footnote id="F3">On March 20, 2020, an indirect subsidiary of the Issuer entered into a Loan Agreement (the &quot;Loan Agreement&quot;) with TJMT Holdings LLC (the &quot;Lender&quot;) providing for unsecured term loans from time to time (the &quot;Loans&quot;) in an aggregate original principal amount not to exceed $300 million. Upon the execution of and in consideration for the Lender's commitments under the Loan Agreement, TJMT Holdings LLC received a warrant (the &quot;Warrant&quot;) to purchase shares of Class A Common Stock.  Pursuant to the Warrant, the Lender may purchase up to 3,000,000 shares of Class A common stock, which number of shares will be increased to 10,000,000 if, at any time during the term of the Loan Agreement, Loans equal to or greater than $100 million remain outstanding for a certain period of time specified in the Warrant.</footnote>
        <footnote id="F4">The exercise price per share of the Class A Common Stock issuable pursuant to the Warrant is equal to the average of the volume weighted average prices of the Class A Common Stock for the ten (10) trading days following the date on which the Issuer publicly announced its earnings results for the first quarter of 2020, which was May 7, 2020.</footnote>
        <footnote id="F5">Pursuant to the terms of the Exchange Agreement, effective as of April 15, 2015, by and among the Issuer, Virtu Financial LLC and the equityholders of Virtu Financial LLC (the &quot;Exchange Agreement&quot;), Virtu Financial Units, together with a corresponding number of shares of Class C Common Stock, may be exchanged for shares of Class A Common Stock, which have one vote per share and economic rights (including rights to dividends and distributions upon liquidation), on a one-for-one basis at the discretion of the holder. The exchange rights under the Exchange Agreement do not expire.</footnote>
        <footnote id="F6">Pursuant to the terms of the Exchange Agreement, effective as of April 15, 2015, by and among the Issuer, Virtu Financial LLC and the equityholders of Virtu Financial LLC (the &quot;Exchange Agreement&quot;), Virtu Financial Units, together with a corresponding number of shares of Class D Common Stock, may be exchanged for shares of Class B common stock of the Issuer (&quot;Class B Common Stock&quot;), which have 10 votes per share and economic rights (including rights to dividends and distributions upon liquidation), on a one-for-one basis at the discretion of the holder. The exchange rights under the Exchange Agreement do not expire. Pursuant to the terms of the Issuer's Certificate of Incorporation, the shares of Class B Common Stock may be converted into shares of Class A Common Stock on a one-for-one basis at the discretion of the holder.</footnote>
        <footnote id="F7">Mr. Michael Viola and Mrs. Teresa Viola each have an indirect interest in the securities held by TJMT, a Viola family vehicle over which each of the reporting persons share dispositive control and voting control.</footnote>
    </footnotes>

    <remarks>By virtue of their relationships with Mr. Vincent Viola and Mr. Michael Viola, directors of the Issuer, Mrs. Teresa Viola and TJMT Holdings LLC may each be deemed to be a director by deputization.  By virtue of his relationship with Mr. Michael Viola and Mrs. Teresa Viola, Mr. Vincent Viola is deemed to have a beneficial interest in the shares owned by TJMT Holdings LLC.</remarks>

    <ownerSignature>
        <signatureName>/s/ Justin Waldie, as Attorney-in-Fact for TJMT Holdings LLC</signatureName>
        <signatureDate>2020-05-22</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Justin Waldie, as Attorney-in-Fact for Michael Viola</signatureName>
        <signatureDate>2020-05-22</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Justin Waldie, as Attorney-in-Fact for Teresa Viola</signatureName>
        <signatureDate>2020-05-22</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Justin Waldie, as Attorney-In-Fact for Vincent Viola</signatureName>
        <signatureDate>2020-05-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
