John M. Heyneman Jr - Sep 9, 2025 Form 4 Insider Report for FIRST INTERSTATE BANCSYSTEM INC (FIBK)

Role: Director, 10%+ Owner
Signature: /s/ Kirk D. Jensen, Attorney-in-Fact for Reporting Person
Stock symbol: FIBK
Transactions as of: Sep 9, 2025
Transactions value $: -$1,123,300
Form type: 4
Date filed: 11/12/2025, 04:46 PM
Previous filing: Aug 18, 2025
Next filing: Nov 14, 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
HEYNEMAN JOHN M JR	Director, 10%+ Owner	P.O. BOX 30918, BILLINGS	/s/ Kirk D. Jensen, Attorney-in-Fact for Reporting Person	2025-11-12	0001198518

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	FIBK	Common Stock	Will/Inheritance	$0	+30.4K	+2.15%	$0.00	1.45M	Sep 9, 2025	see footnote	F1, F2
transaction	FIBK	Common Stock	Will/Inheritance	$0	+45.2K		$0.00	45.2K	Sep 10, 2025	By Bench Ranch LLC	F1
transaction	FIBK	Common Stock	Will/Inheritance	$0	+67.5K		$0.00	67.5K	Sep 17, 2025	By Awe' LLC	F1
transaction	FIBK	Common Stock	Sale	-$641K	-20K	-29.64%	$32.06	47.5K	Nov 10, 2025	By Awe' LLC	F1
transaction	FIBK	Common Stock	Sale	-$482K	-15K	-33.22%	$32.14	30.2K	Nov 11, 2025	By Bench Ranch LLC	F1

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	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 Table I being made from John Heyneman, Jr.'s perspective. The nature of beneficial ownership is described in detail by footnote for all reporting persons.
F2	Composed of 180,432 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, 4,552 shares held of record by John Heyneman, Jr.'s spouse, 1,095 shares held of record by John Heyneman, Jr.'s daughter, 1,215 shares held of record by John Heyneman, Jr.'s son Quinn, and 310 shares held of record by John Heyneman, Jr.'s son Bae-John.

Content

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 Table I being made from John Heyneman, Jr.'s perspective. The nature of beneficial ownership is described in detail by footnote for all reporting persons.

Composed of 180,432 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, 4,552 shares held of record by John Heyneman, Jr.'s spouse, 1,095 shares held of record by John Heyneman, Jr.'s daughter, 1,215 shares held of record by John Heyneman, Jr.'s son Quinn, and 310 shares held of record by John Heyneman, Jr.'s son Bae-John.