UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington D.C. 20549

------------------------------

FORM 8-K

------------------------------

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of report (date of earliest event reported): ~~September~~October 310, 2025

------------------------------

FIRST INTERSTATE BANCSYSTEM, INC.

(Exact name of registrant as specified in its charter)

------------------------------

Delaware

001-34653

81-0331430

(State or other jurisdiction of
incorporation or organization)

(Commission
File No.)

(IRS Employer
Identification No.)

401 North 31st Street

Billings,

59101

(Address of principal executive offices)

(zip code)


	(406)	255-5311
(Registrant’s telephone number, including area code)

	Not Applicable
(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a- 12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

* * * * *

Securities registered pursuant to Section 12(b) of the Act:


Title of each class	Trading Symbol(s)	Name of exchange on which registered
Common stock, $0.00001 par value	FIBK	NASDAQ

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

* * * * *

Item 57.0201. ~~Departure~~Regulation ofFD ~~Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers~~Disclosure.

On ~~September~~October 310, 2025, First Interstate BancSystem, Inc. ~~(the “Company”) disclosed that, in connection with its internal realignment of senior management under the direction of the Company~~’s ~~President~~wholly ~~and~~owned ~~Chief Executive Officer~~subsidiary, ~~James~~First A.Interstate ~~Reuter,~~Bank ~~effective~~(“First ~~as of September 10~~Interstate”), ~~2025,~~closed the ~~Company’s Chief Banking Officer position would be separated and transitioned to a two person Co~~previously-~~Chief~~announced ~~Banking~~transaction ~~Officer position,~~ with ~~Lorrie~~Enterprise ~~Asker,~~Bank ~~the~~& ~~Company’s~~Trust ~~former~~(“Enterprise ~~sole~~Bank”), ~~Chief Banking Officer and~~ a ~~named~~wholly ~~executive~~owned ~~officer~~subsidiary inof ~~the~~Enterprise ~~Company’s~~Financial ~~2024~~Services ~~annual meeting proxy statement~~Corp, ~~being~~pursuant ~~appointed~~ to ~~serve~~which asEnterprise ~~one~~Bank ~~Co-Chief~~acquired ~~Banking Officer and, as described further below, Chris Shepler being appointed to serve as~~ the ~~other~~twelve ~~Co-Chief~~branches ~~Banking~~previously ~~Officer.~~identified ~~Except for the change~~ in ~~title~~Arizona and ~~responsibilities~~Kansas ~~described herein, no other changes or amendments or modifications were made to Ms. Asker’s employment with~~ (the ~~Company.~~"Branches") ~~The~~from ~~Company~~First ~~believes~~Interstate, ~~like~~including ~~other~~specified ~~financial~~deposits ~~institutions of a similar or larger size~~ and ~~geographical reach~~loans, ~~that~~the ~~adding~~owned toreal ~~its~~estate, ~~leadership~~and infixed ~~this~~and ~~position~~other ~~will~~assets ~~improve~~associated ~~its~~with ~~operations and benefit~~ the ~~organization and its stockholders~~Branches.

Information contained in Item 7.01 ~~Regulation~~of FDthis ~~Disclosure~~Current Report on Form 8-K shall neither be deemed filed for purposes of the Securities Exchange Act of 1934, as amended, nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as expressly set forth by specific reference in such a filing.

On September 3, 2025, the Company appointed Mr. Shepler accepted the Company’s appointment as Co-Chief Banking Officer for the Company effective as of September 10, 2025. Mr. Shepler has more than 30 years of leadership experience in commercial, business, wealth, and consumer/small business banking, and he most recently served as Managing Director and National Commercial Banking Region Coverage Executive at Wells Fargo. In his role as Co-Chief Banking Officer, Mr. Shepler will cover branches in Colorado, Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, and South Dakota, and in her new role as Co-Chief Banking Officer, Ms. Asker will cover branches in Arizona, Idaho, Montana, Oregon, Washington, and Wyoming. There was no arrangement or understanding with any other person pursuant to which Mr. Shepler was appointed to this position, and since the beginning of the Company’s last fiscal year, Mr. Shepler has not engaged in any transaction with the Company that would be reportable as a related person transaction under applicable rules of the Securities and Exchange Commission.

Cautionary Note Regarding Forward-Looking Statements

Statements contained in this report constitute “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. These statements are predictive in nature and are identified by the use of the terms “expected,” “will,” “look forward to,” “aim,” and similar words or phrases indicating possible future expectations, events or actions. Such forward-looking statements are based on current expectations, assumptions and projections about our business and the Company, and are not guarantees of our future performance or outcomes. These statements are subject to a number of known and unknown risks, uncertainties, and other factors, many of which are beyond our ability to control or predict, which may cause actual events to be materially different from those expressed or implied herein. The Company has provided additional information about the risks facing its business in its most recent annual report on Form 10-K, and any subsequent periodic and current reports on Forms 10-Q and 8-K, filed by it with the Securities and Exchange Commission. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date the statement was made and are expressly qualified in their entirety by the cautionary statements set forth herein and in the filings with the Securities and Exchange Commission identified above, which you should read in their entirety before making any investment or other decision with respect to our securities. We undertake no obligation to update or revise any forward-looking statements contained in this report, whether as a result of new information, future events or otherwise, except as otherwise required by applicable law.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.


			Exhibit No.						Exhibit Description



			104						Cover Page Interactive Data File (embedded within Inline XBRL document).

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the ~~Registrant~~registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

~~Date~~Dated: ~~September~~October 914, 2025

FIRST INTERSTATE BANCSYSTEM, INC. By: /s/ ~~JAMES~~KIRK AD. ~~REUTER~~JENSEN ~~James~~Kirk AD. ~~Reuter~~Jensen Executive Vice President, ~~and~~General ~~Chief~~Counsel ~~Executive~~and ~~Officer~~Secretary

Filing Compare · FIRST INTERSTATE BANCSYSTEM INC