FIRST INTERSTATE BANCSYSTEM INC

The Audit Committee of the Board appointed Ernst & Young LLP (“EY”) to be our independent

registered public accounting firm for the year ending December 31, 2025. While the Audit Committee

is directly responsible for the appointment, compensation, retention, and oversight of our independent

registered public accounting firm, the Audit Committee has requested that the Board submit the

selection of EY to our shareholders for ratification as a matter of good corporate governance. A

representative of EY is expected to be present at the annual meeting, will have an opportunity to

make a statement at the meeting if they desire to do so, and will have the opportunity to respond to

questions, if any.

Neither the Audit Committee nor the Board is required to take any action as a result of the outcome of

the vote on this proposal. If our shareholders do not ratify the selection of EY as our independent

registered public accounting firm, however, the Audit Committee will consider whether to retain EY or

to select another independent registered public accounting firm. Furthermore, even if the selection is

ratified, the Audit Committee in its discretion may appoint a different independent registered public

accounting firm at any time during the year if it determines that such a change is in the best interest

of the Company and our shareholders.

If a quorum is present at the annual meeting and if the votes cast for the ratification of EY by shares

present in person or represented by proxy at the meeting and entitled to vote on the matter exceed

the votes cast against the ratification of EY by shares present in person or represented by proxy at the

meeting and entitled to vote on the matter then the appointment of EY as the Company’s independent

registered public accounting firm for the year ending December 31, 2025, will be ratified. The persons

named as proxies in the proxy card accompanying these materials will vote the shares represented by a

validly executed proxy card for the ratification of the selection of EY as the independent registered

public accounting firm unless a vote against the proposal or an abstention is specifically indicated on

the proxy card in respect of this proposal.

Changes in Certifying Accountant

As previously reported, on November 28, 2023, in connection with the change to our new independent

registered public accounting firm, EY, for the fiscal year ending December 31, 2024, the Audit

Committee approved the dismissal of RSM as our independent registered public accounting firm

following its completion of the audit of our consolidated financial statements for the fiscal year ended

December 31, 2023.

The reports of RSM on our consolidated financial statements for the fiscal years ended December 31,

2022 and December 31, 2023, and the subsequent interim period from January 1, 2024 through the

completion of RSM’s audit of our consolidated financial statements for the fiscal year ended December

31, 2023, did not contain an adverse opinion or a disclaimer of opinion, and were not qualified or

modified as to uncertainty, audit scope, or accounting principles.

statements for the fiscal year ended December 31, 2023, there were no “disagreements” (as defined in

Item 304(a)(1)(iv) of Regulation S-K promulgated under the Securities Exchange Act of 1934, as

amended (“Regulation S-K”) and the related instructions thereto) with RSM on any matter of

accounting principles or practices, financial statement disclosure, or auditing scope or procedure,

which disagreements, if not resolved to the satisfaction of RSM, would have caused RSM to make

reference thereto in connection with its reports on our consolidated financial statements for such

years.

statements for the fiscal year ended December 31, 2023, there were no “reportable events” (as

defined in Item 304(a)(1)(v) of Regulation S-K).

In response to Item 304(a) of Regulation S-K, we provided RSM with a copy of the disclosures we made

on a Form 8-K filed with the SEC on November 30, 2023, prior to the time the Form 8-K was filed. The

Form 8-K reported the change in our independent registered public accounting firm and contained

substantially the same disclosures as above. We requested RSM to furnish us a letter addressed to the

SEC stating whether it agreed with the statements made in the Form 8-K, and if not, stating the

respects in which it does not agree. We received the requested letter from RSM agreeing with our

statements concerning their work for us and a copy of that letter was filed as an exhibit to the Form 8-

K.

statements for the fiscal year ended December 31, 2023, neither we, nor anyone acting on our behalf,

consulted EY regarding either (i) the application of accounting principles to a specified transaction,

either completed or proposed, or the type of audit opinion that might be rendered on our consolidated

financial statements, and no written report or oral advice was provided to us that EY concluded was an

important factor considered by us in reaching a decision as to any accounting, auditing, or financial

reporting issue; or (ii) any matter that was the subject of a “disagreement” (as defined in Item

304(a)(1)(iv) of Regulation S-K and the related instructions thereto) or a “reportable event” (as

described in Item 304(a)(1)(v) of Regulation S-K).

Audit Committee Pre-Approval Policies and Procedures

The Audit Committee charter requires advance approval of all audit and non-audit services performed

by the independent registered public accounting firm to assure that such services do not impair the

auditor’s independence from the Company. The Audit Committee may delegate the authority to pre-

approve services to the Audit Committee chair, subject to ratification by the Audit Committee at its

next committee meeting. In 2023 and 2024, all of the fees paid to RSM and EY, our independent

auditors during those respective years, were approved in advance by the Audit Committee.

Principal Accounting Fees and Services

EY served as the Company’s independent registered public accounting for the completion of its audit

for our fiscal year ended December 31, 2024. RSM served as the Company’s independent registered

public accounting firm from 2004 through the completion of its audit for our fiscal year ended

December 31, 2023. EY and RSM were paid the following fees for services performed as the Company’s

independent registered public accounting firm during the fiscal year ended December 31, 2024 and

RSM was paid the following fees for services performed as the Company’s independent registered

public accounting firm during the fiscal year ended December 31, 2023: