<?xml version="1.0"?><?xml-stylesheet type="text/xsl" href="/Pages/Form4.xsl"?>
<ownershipDocument>

    <schemaVersion>X0304</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-11-09</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001063761</issuerCik>
        <issuerName>SIMON PROPERTY GROUP INC /DE/</issuerName>
        <issuerTradingSymbol>SPG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001235745</rptOwnerCik>
            <rptOwnerName>SIMON HERBERT</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>225 W. WASHINGTON STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>INDIANAPOLIS</rptOwnerCity>
            <rptOwnerState>IN</rptOwnerState>
            <rptOwnerZipCode>46204</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman Emeritus of the Board</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2011-11-09</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>70017</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>128.1176</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1487974</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By the Herbert Simon Revocable Trust</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2011-11-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>51807</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>128.0488</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1436167</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By the Herbert Simon Revocable Trust</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The reporting person is the trustee of the Herbert Simon Revocable Trust (the &quot;Trust&quot;), who disclaims beneficial ownership except to the extent of his pecuniary interest therein.</footnote>
        <footnote id="F2">23,553 of the shares sold were held by MH Holdings, Inc. (&quot;MH&quot;).  The Trust is the 100% owner of MH.  The balance of the shares sold were owned by the Trust.</footnote>
        <footnote id="F3">All 51,807 shares were sold by the Trust.</footnote>
        <footnote id="F4">Total number of shares includes: a. 232,680 shares owned by the the Trust.  b. 30.94% of the shares held by Melvin Simon &amp; Associates, Inc., (&quot;MSA&quot;), or 167,167 shares.  The Trust owns 30.94% of MSA.  c. 30.94% of the shares held by Voting Trust formed pursuant to a Second Amended and Restated Voting Trust Agreement, Voting Agreement and Proxy entered into as of March 1, 2004 between Melvin Simon &amp; Associates, Inc., an Indiana corporation and Melvin Simon, Herbert Simon and David Simon (&quot;Voting Trust&quot;), or 1,036,320 shares.  The Trust owns 30.94% of the economic interest of the Voting Trust.  Does not include shares that may be issued upon the exchange of units of partnership interest in Simon Property Group, L.P. (&quot;Units&quot;).  Units held by limited partners are exchangeable either for shares of Common (on a one-to-one basis) or for cash.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Herbert Simon, and his attorney-in-fact, Shelly Doran</signatureName>
        <signatureDate>2011-11-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
