<SEC-DOCUMENT>0000860413-22-000075.txt : 20220304
<SEC-HEADER>0000860413-22-000075.hdr.sgml : 20220304
<ACCEPTANCE-DATETIME>20220304183324
ACCESSION NUMBER:		0000860413-22-000075
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20220302
FILED AS OF DATE:		20220304
DATE AS OF CHANGE:		20220304

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SCOTT JULIE A
		CENTRAL INDEX KEY:			0001234619

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34653
		FILM NUMBER:		22715685

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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SCOTT THOMAS W
		CENTRAL INDEX KEY:			0001198535

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34653
		FILM NUMBER:		22715684

	MAIL ADDRESS:	
		STREET 1:		C/O FIRST INTERSTATE BANCSYSTEM INC
		STREET 2:		P O BOX 30918
		CITY:			BILLINGS
		STATE:			MT
		ZIP:			59116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Exempt Thomas W Scott Marital Trust 2
		CENTRAL INDEX KEY:			0001909336
		STATE OF INCORPORATION:			WY
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34653
		FILM NUMBER:		22715682

	BUSINESS ADDRESS:	
		STREET 1:		PO BOX 2007
		CITY:			SHERIDAN
		STATE:			WY
		ZIP:			82801
		BUSINESS PHONE:		307-672-1491

	MAIL ADDRESS:	
		STREET 1:		PO BOX 2007
		CITY:			SHERIDAN
		STATE:			WY
		ZIP:			82801

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Thomas W Scott Trust Dtd 8/22/95, Thomas W Scott Trustee
		CENTRAL INDEX KEY:			0001908858
		STATE OF INCORPORATION:			WY
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34653
		FILM NUMBER:		22715683

	BUSINESS ADDRESS:	
		STREET 1:		FIRST INTERSTATE BANK, TRUSTEE
		STREET 2:		PO BOX 2007
		CITY:			SHERIDAN
		STATE:			WY
		ZIP:			82801
		BUSINESS PHONE:		307-672-1491

	MAIL ADDRESS:	
		STREET 1:		FIRST INTERSTATE BANK, TRUSTEE
		STREET 2:		PO BOX 2007
		CITY:			SHERIDAN
		STATE:			WY
		ZIP:			82801

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>4
<SEQUENCE>1
<FILENAME>wf-form4_164643678741517.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2022-03-02</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001234619</rptOwnerCik>
            <rptOwnerName>SCOTT JULIE A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>31 BUSBEE ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ASHEVILLE</rptOwnerCity>
            <rptOwnerState>NC</rptOwnerState>
            <rptOwnerZipCode>28803</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001909336</rptOwnerCik>
            <rptOwnerName>Exempt Thomas W Scott Marital Trust 2</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>FIRST INTERSTATE BANK, TRUSTEE</rptOwnerStreet1>
            <rptOwnerStreet2>P.O. BOX 2007</rptOwnerStreet2>
            <rptOwnerCity>SHERIDAN</rptOwnerCity>
            <rptOwnerState>WY</rptOwnerState>
            <rptOwnerZipCode>82801</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001198535</rptOwnerCik>
            <rptOwnerName>SCOTT THOMAS W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>FIRST INTERSTATE BANK, TRUSTEE</rptOwnerStreet1>
            <rptOwnerStreet2>P.O. BOX 2007</rptOwnerStreet2>
            <rptOwnerCity>SHERIDAN</rptOwnerCity>
            <rptOwnerState>WY</rptOwnerState>
            <rptOwnerZipCode>82801</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001908858</rptOwnerCik>
            <rptOwnerName>Thomas W Scott Trust Dtd 8/22/95, Thomas W Scott Trustee</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>FIRST INTERSTATE BANK, TRUSTEE</rptOwnerStreet1>
            <rptOwnerStreet2>P.O. BOX 2007</rptOwnerStreet2>
            <rptOwnerCity>SHERIDAN</rptOwnerCity>
            <rptOwnerState>WY</rptOwnerState>
            <rptOwnerZipCode>82801</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2022-03-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>C</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>25700</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>573956</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>see footnote</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Class B Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.0</value>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2022-03-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>C</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>25700</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>25700.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2363457</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>see footnote</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeHolding>
            <securityTitle>
                <value>Class B Common Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.0</value>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1933.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1933</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">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="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 Julie A Scott.</footnote>
        <footnote id="F3">Composed of 131,731 shares held of record by Juliana Sarah Scott Rose Trust, 131,731 shares held of record by Elizabeth Lauren Scott Rose Trust, 94,863 shares held of record by Holland Elizabeth Scott Trust, 94,863 shares held of record by Harper Grace Scott Trust, 94,863 shares held of record by Harrison William Scott Trust, 25,700 shares held of record by IXL Limited Liability Company, and 205 shares held of record by the estate of Thomas W Scott.</footnote>
        <footnote id="F4">Composed of 397,210 shares held of record by Julie A Scott Rose Trustee of the Julie A Scott Rose Trust Dated 5-14-2002, 10,424 shares held of record by First Interstate Bank &amp; Julie Scott Rose, Co-TTEEs of the Joan D Scott Trust Dtd 10/16/12, 196,828 shares held of record by IXL Limited Liability Company, 1,669,660 shares held of record by Thomas W Scott Trust Dtd 8/22/95, Thomas W Scott Trustee, and 89,335 shares held of record by Exempt Thomas W Scott Marital Trust 2.</footnote>
    </footnotes>

    <remarks>Form 2 of 2</remarks>

    <ownerSignature>
        <signatureName>THOMAS W SCOTT TRUST DTD 8/22/95, THOMAS W SCOTT TRUSTEE, By: **</signatureName>
        <signatureDate>2022-03-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>EXEMPT THOMAS W SCOTT MARITAL TRUST 2, By: **</signatureName>
        <signatureDate>2022-03-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>THOMAS W SCOTT, By: **</signatureName>
        <signatureDate>2022-03-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Julie Scott Rose, By **</signatureName>
        <signatureDate>2022-03-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>**By: /s/ Timothy Leuthold, Attorney-in-Fact</signatureName>
        <signatureDate>2022-03-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
