<SEC-DOCUMENT>0001140361-18-003126.txt : 20180124
<SEC-HEADER>0001140361-18-003126.hdr.sgml : 20180124
<ACCEPTANCE-DATETIME>20180124195720
ACCESSION NUMBER:		0001140361-18-003126
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180122
FILED AS OF DATE:		20180124
DATE AS OF CHANGE:		20180124

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Nemser Earl H
		CENTRAL INDEX KEY:			0001391400

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33440
		FILM NUMBER:		18546432

	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>2018-01-22</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001391400</rptOwnerCik>
            <rptOwnerName>Nemser Earl H</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>Vice Chairman</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-01-22</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>32000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>62.80</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>68610</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $62.70 to $63.05, inclusive.  The reporting person undertakes to provide Interactive Brokers Group, Inc. (the &quot;Company&quot;), any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each price within the ranges set forth in this footnote to this Form 4.</footnote>
        <footnote id="F2">This amount includes (a) Class A common stock attributable to vested restricted stock units that were awarded under the 2007 Stock Incentive Plan (&quot;Plan&quot;), (b) unvested restricted stock units that were awarded under the Plan, and (c) 5,025 restricted stock units that will be issued under the amended 2007 Stock Incentive Plan (&quot;Amended Plan&quot;) subject to shareholder approval of the Amended Plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Raymond Bussiere as authorized signatory for Earl H. Nemser</signatureName>
        <signatureDate>2018-01-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
