<SEC-DOCUMENT>0000860413-22-000077.txt : 20220310
<SEC-HEADER>0000860413-22-000077.hdr.sgml : 20220310
<ACCEPTANCE-DATETIME>20220310180233
ACCESSION NUMBER:		0000860413-22-000077
CONFORMED SUBMISSION TYPE:	3/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20220201
FILED AS OF DATE:		20220310
DATE AS OF CHANGE:		20220310

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Scott Jonathan R
		CENTRAL INDEX KEY:			0001361935

	FILING VALUES:
		FORM TYPE:		3/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34653
		FILM NUMBER:		22730368

	MAIL ADDRESS:	
		STREET 1:		P.O. BOX 30918
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59116

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FIRST INTERSTATE BANCSYSTEM INC
		CENTRAL INDEX KEY:			0000860413
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		IRS NUMBER:				810331430
		STATE OF INCORPORATION:			MT
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		P O BOX 30918
		STREET 2:		401 NO 31ST STREET
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59116-0918
		BUSINESS PHONE:		4062555300

	MAIL ADDRESS:	
		STREET 1:		P O BOX 30918
		STREET 2:		401 NO 31ST STREET
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59116-0918

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	FIRST INTERSTATE BANCSYSTEM OF MONTANA INC
		DATE OF NAME CHANGE:	19930615
</SEC-HEADER>
<DOCUMENT>
<TYPE>3/A
<SEQUENCE>1
<FILENAME>wf-form3a_164695333512689.xml
<DESCRIPTION>FORM 3/A
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3/A</documentType>

    <periodOfReport>2022-02-01</periodOfReport>

    <dateOfOriginalSubmission>2022-02-11</dateOfOriginalSubmission>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000860413</issuerCik>
        <issuerName>FIRST INTERSTATE BANCSYSTEM INC</issuerName>
        <issuerTradingSymbol>FIBK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001361935</rptOwnerCik>
            <rptOwnerName>Scott Jonathan R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PO BOX 7113</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BILLINGS</rptOwnerCity>
            <rptOwnerState>MT</rptOwnerState>
            <rptOwnerZipCode>59103</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>284589</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Class B Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.0</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>813259.0</value>
                    <footnoteId id="F4"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>see footnote</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Class B Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.0</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>265.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Composed of 94,863 shares held of record by Holland Elizabeth Scott Trust, 94,683 shares held of record by Harper Grace Scott Trust, and 94,863 shares held of record by Harrison William Scott Trust</footnote>
        <footnote id="F2">As a result of certain agreements entered into by and among the reporting persons, the Issuer, and certain other stockholders of the Issuer, the reporting persons may be deemed members of a group with the other signatories thereto and may be deemed to share beneficial ownership of the securities reported herein. Each of the reporting persons disclaims beneficial ownership of any such securities, except to the extent of its pecuniary interest therein. The reporting persons expect to file future Forms 4, if any, together with Jonathan R. Scott with the indication of direct or indirect ownership in Tables I and II being made from Jonathan R. Scott's perspective.  The nature of beneficial ownership is described in detail by footnote for all reporting persons.</footnote>
        <footnote id="F3">The Class B Common Stock is convertible at any time into Class A Common Stock on a share for share basis at the discretion of the holder.  The conversion feature of the Class B Common Stock does not expire.</footnote>
        <footnote id="F4">Composed of 540,731 shares held of record by Jonathan Scott as Trustee of the Jonathan R Scott Trust Dated as of 4/21/04, 222,528 shares held of record by IXL Limited Liability Company and 50,000 shares held of record by Jonathan Scott's spouse.</footnote>
    </footnotes>

    <remarks>This amendment is being filed solely to reflect indirect holdings originally inadvertently omitted and to add three reporting persons who expect to file future Forms 4 and 5, if any, together with Jonathan R. Scott.</remarks>

    <ownerSignature>
        <signatureName>JONATHAN R. SCOTT, By: /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person</signatureName>
        <signatureDate>2022-03-10</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>JONATHAN SCOTT AS TRUSTEE OF THE JONATHAN R SCOTT TRUST DATED AS OF 4/21/04, By: /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person</signatureName>
        <signatureDate>2022-03-10</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>HOLLAND ELIZABETH SCOTT TRUST, By: /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person</signatureName>
        <signatureDate>2022-03-10</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>HARRISON WILLIAM SCOTT TRUST, By: /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person</signatureName>
        <signatureDate>2022-03-10</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>HARPER GRACE SCOTT TRUST, By: /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person</signatureName>
        <signatureDate>2022-03-10</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
