Vanguard Reports 10% Stake in First Interstate BancSystem (FIBK)

Rhea-AI Filing Summary

First Interstate BancSystem Inc filed an amendment to a Schedule 13G reporting beneficial ownership of 10% of its common stock, equal to 10,119,518 shares. The filing states January 12, 2026 as the date The Vanguard Group, Inc. completed an internal realignment; the amendment explains that certain subsidiaries or business divisions will report beneficial ownership separately going forward. The filing lists shared voting power of 698,080 shares and shared dispositive power of 10,119,518, and is signed by Ashley Grim on 03/05/2026.

Insights

Institutional Ownership Analyst

Vanguard reports a 10% stake through shared dispositive authority.

The amendment states beneficial ownership of 10,119,518 shares representing 10% of common stock, with shared voting power of 698,080 and shared dispositive power of 10,119,518. These figures are presented as of the amendment filing.

Timing and allocation changes are tied to an internal realignment effective January 12, 2026; subsequent filings by subsidiaries are indicated. Future disclosures by Vanguard subsidiaries will clarify voting and dispositive splits.

Corporate Governance Expert

The filing documents ownership structure changes after Vanguard's internal reorganization.

The amendment quotes that on January 12, 2026 Vanguard "no longer performs portfolio management services or administers proxy voting" at the parent level and expects subsidiaries to "report beneficial ownership separately." The statement reproduces language from SEC Release No. 34-39538.

Practical implications depend on which subsidiaries later file disaggregated 13G/A reports; watch for those filings to see any shifts in reported voting power or dispositive authority.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 9)

First Interstate BancSystem Inc

(Name of Issuer)

Common Stock

(Title of Class of Securities)

02/27/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP Number(s):

1

Names of Reporting Persons

The Vanguard Group

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

PENNSYLVANIA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 698,080.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 10,119,518.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

10,119,518.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

10 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: On January 12, 2026, The Vanguard Group, Inc. went through an internal realignment. As of that date, The Vanguard Group, Inc. no longer performs portfolio management services or administers proxy voting. In accordance with SEC Release No. 34-39538 (January 12, 1998), The Vanguard Group, Inc. anticipates that certain subsidiaries or business divisions of subsidiaries of The Vanguard Group, Inc., that currently have, or are deemed to have, beneficial ownership with The Vanguard Group, Inc., will report beneficial ownership separately (on a disaggregated basis) from The Vanguard Group, Inc. in reliance on such release. These subsidiaries and/or business divisions pursue the same investment strategies as previously pursued by The Vanguard Group, Inc. prior to the realignment.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: First Interstate BancSystem Inc
(b)	Address of issuer's principal executive offices: PO Box 30918, 401 North 31st Street, Billings, MT, 59107
Item 2.
(a)	Name of person filing: The Vanguard Group
(b)	Address or principal business office or, if none, residence: 100 Vanguard Blvd., Malvern, PA 19355
(c)	Citizenship: PA
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 32055Y201
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 10119518
(b)	Percent of class: 10 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 698080
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 10119518
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. The Vanguard Group, Inc.'s clients, including investment companies registered under the Investment Company Act of 1940 and other managed accounts, have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the securities reported herein. No one other person's interest in the securities reported herein is more than 5%.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

The Vanguard Group

Signature:	Ashley Grim
Name/Title:	Head of Global Fund Administration
Date:	03/05/2026

FAQ

What stake does The Vanguard Group report in FIBK?

The Vanguard Group reports beneficial ownership of 10,119,518 shares, equal to 10% of common stock. The filing lists shared dispositive power over those shares and shared voting power of 698,080.

Does Vanguard claim sole voting or dispositive power in FIBK?

No. The filing states 0 shares with sole voting power and 0 shares with sole dispositive power, showing only shared voting and dispositive authority as reported.

Why does the filing mention an internal realignment dated January 12, 2026?

The amendment explains that on January 12, 2026 Vanguard underwent an internal realignment and expects certain subsidiaries to report beneficial ownership separately in reliance on SEC Release No. 34-39538.

Who signed the Schedule 13G/A amendment for FIBK?

The Schedule 13G/A amendment is signed by Ashley Grim, whose title is Head of Global Fund Administration, with a signature date of 03/05/2026.

Will Vanguard’s subsidiaries file separate ownership reports for FIBK?

The amendment states Vanguard "anticipates" that certain subsidiaries or business divisions will report beneficial ownership separately; subsequent filings by those entities are expected to show disaggregated ownership reporting.