<SEC-DOCUMENT>0001140361-18-025213.txt : 20180522
<SEC-HEADER>0001140361-18-025213.hdr.sgml : 20180522
<ACCEPTANCE-DATETIME>20180522164935
ACCESSION NUMBER:		0001140361-18-025213
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180509
FILED AS OF DATE:		20180522
DATE AS OF CHANGE:		20180522

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Brody Paul Jonathan
		CENTRAL INDEX KEY:			0001391403

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33440
		FILM NUMBER:		18852950

	MAIL ADDRESS:	
		STREET 1:		ONE PICKWICK PLAZA
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Interactive Brokers Group, Inc.
		CENTRAL INDEX KEY:			0001381197
		STANDARD INDUSTRIAL CLASSIFICATION:	SECURITY BROKERS, DEALERS & FLOTATION COMPANIES [6211]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		ONE PICKWICK PLAZA
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830
		BUSINESS PHONE:		203-618-5800

	MAIL ADDRESS:	
		STREET 1:		ONE PICKWICK PLAZA
		CITY:			GREENWICH
		STATE:			CT
		ZIP:			06830
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-05-09</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001381197</issuerCik>
        <issuerName>Interactive Brokers Group, Inc.</issuerName>
        <issuerTradingSymbol>IBKR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001391403</rptOwnerCik>
            <rptOwnerName>Brody Paul Jonathan</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE PICKWICK PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Financial Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-05-09</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2018-05-21</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>38626</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>79.24</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>603644</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The price represents the closing price of the issuer's Class A common stock as of May 9, 2018, the vesting date.</footnote>
        <footnote id="F2">This amount includes (a) Class A common stock attributable to vested restricted stock units that were awarded under the amended 2007 Stock Incentive Plan (&quot;Plan&quot;) and  (b) unvested restricted stock units that were awarded under the Plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Raymond Bussiere as authorized signatory for Paul J. Brody</signatureName>
        <signatureDate>2018-05-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
