Sec Form 3/A Filing - HEYNEMAN JOHN M JR @ FIRST INTERSTATE BANCSYSTEM INC - 2022-02-01

FORM 3/A Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person HEYNEMAN JOHN M JR 2. Issuer Name and Ticker or Trading Symbol FIRST INTERSTATE BANCSYSTEM INC [ FIBK] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) P.O. BOX 7113, 3. Date of Earliest Transaction (MM/DD/YY) 02/01/2022 (Street) BILLINGS, MT59103 4. If Amendment, Date Original Filed (MM/DD/YY) 02/11/2022 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Class A Common Stock 1,445( 1 ) I see footnote( 1 )( 2 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Class A Common Stock $ 0 ( 3 ) ( 3 ) Class A Common Stock 1,400,617( 4 ) I see footnote( 2 )( 4 ) Class B Common Stock $ 0 ( 3 ) ( 3 ) Class A Common Stock 15,000 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other HEYNEMAN JOHN M JR P.O. BOX 7113, BILLINGS, MT59103 X X John M Heyneman Jr. Trust 4100 BIG HORN AVE. SHERIDAN, WY82801 X Rae Ann Morss & John Heyneman Jr., Trustees FBO Rae Ann Morss Exemption Trust Under the Scott Family 1996 Trust P.O. BOX 7113 BILLINGS, MT59103 X Riki Rae Scott Davidson & John Heyneman Jr., Trustees FBO Riki Scott Davidson Exemption Trust Under the Scott Family 1996 Trust P.O. BOX 7113 BILLINGS, MT59103 X Towanda Investments Limited Partnership 4100 BIG HORN AVE SHERIDAN, MT82801 X Signatures JOHN M HEYNEMAN JR. TRUST, By: /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person 03/22/2022 Signature of Reporting Person Date RAE ANN MORSS & JOHN HEYNEMAN JR., TRUSTEES FBO RAE ANN MORSS EXEMPTION TRUST UNDER THE SCOTT FAMILY 1996 TRUST, By: /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person 03/22/2022 Signature of Reporting Person Date RIKI RAE SCOTT DAVIDSON & JOHN HEYNEMAN JR., TRUSTEES FBO RIKI SCOTT DAVIDSON EXEMPTION TRUST UNDER THE SCOTT FAMILY1996 TRUST, By: /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person 03/22/2022 Signature of Reporting Person Date TOWANDA INVESTMENTS LIMITED PARTNERSHIP, By: /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person 03/22/2022 Signature of Reporting Person Date JOHN M. HEYNEMAN, JR., By: /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person 03/22/2022 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Composed of 325 shares held of record by John Heyneman, Jr.'s spouse, 470 shares held by Child 1 and 650 by Child 2 ( 2 )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 and 5, if any, together with John Heyneman, Jr. with the indication of direct or indirect ownership in Tables I and II being made from John Heyneman, Jr.'s perspective. The nature of beneficial ownership is described in detail by footnote for all reporting persons. (by see footnote) ( 3 )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 and the reporting person elected to convert the shares upon receipt. ( 4 )Composed of 139,921 shares held of record by John M Heyneman Jr. Trust, 85,836 shares held of record by Riki Rae Scott Davidson & John Heyneman Jr., Trustees FBO Riki Scott Davidson Exemption Trust Under the Scott Family 1996 Trust, 85,836 shares held of record by Rae Ann Morss & John Heyneman Jr., Trustees FBO Rae Ann Morss Exemption Trust Under the Scott Family 1996 Trust, 1,085,792 shares held of record by Towanda Investments Limited Partnership, and 3,232 shares held of record by John Heyneman, Jr.'s spouse.

Remarks: This amendment is being filed solely to reflect indirect holdings originally inadvertently omitted for spouse and children and identify direct holdings inadvertently reported as indirect.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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