FIBK SEC Filings: 8-K, 10-Q, S-3 & 424B

Financials

TYPE

HEADLINE

FILED AT

10-Q

Form 10-Q - Quarterly report [Sections 13 or 15(d)]

Nov 2, 2026

10-Q

Form 10-Q - Quarterly report [Sections 13 or 15(d)]

Aug 3, 2026

10-Q

Form 10-Q - Quarterly report [Sections 13 or 15(d)]

May 7, 2026

10-K

Form 10-K - Annual report [Section 13 and 15(d), not S-K Item 405]

Feb 26, 2026

10-Q

Form 10-Q - Quarterly report [Sections 13 or 15(d)]

Nov 6, 2025

10-Q

Form 10-Q - Quarterly report [Sections 13 or 15(d)]

Aug 6, 2025

News

TYPE

HEADLINE

FILED AT

8-K

First Interstate BancSystem, Inc. Reports Third Quarter 2026 Results

Oct 22, 2026

8-K

First Interstate BancSystem Executes Employment Agreement with New Executive VP and Chief Operations Officer Jeff Lee

Sep 16, 2026

8-K

First Interstate BancSystem, Inc. Appoints Jeff Lee as Chief Operations Officer

Aug 21, 2026

8-K

First Interstate BancSystem, Inc. Reports Second Quarter 2026 Financial Results

Jul 23, 2026

8-K

First Interstate BancSystem, Inc. Appoints Matthew Ritter and Kevin Turner to Board of Directors

Jul 16, 2026

8-K

First Interstate BancSystem, Inc. Announces Departure of Executive Vice President and General Counsel

Jul 9, 2026

Prospectus

TYPE

HEADLINE

FILED AT

424B5

Form 424B5 - Prospectus [Rule 424(b)(5)]

Jun 6, 2025

424B5

Form 424B5 - Prospectus [Rule 424(b)(5)]

Jun 5, 2025

425

Form 425 - Prospectuses and communications, business combinations

Jan 10, 2022

425

Form 425 - Prospectuses and communications, business combinations

Dec 22, 2021

424B3

Common Stock-

Dec 16, 2021

425

Form 425 - Prospectuses and communications, business combinations

Oct 29, 2021

Registrations

TYPE

HEADLINE

FILED AT

S-3ASR

May 2026 SHELF

May 26, 2026

FWP

Form FWP - Filing under Securities Act Rules 163/433 of free writing prospectuses

Jun 5, 2025

FWP

Form FWP - Filing under Securities Act Rules 163/433 of free writing prospectuses

Jun 5, 2025

S-8

Form S-8 - Securities to be offered to employees in employee benefit plans

May 23, 2024

S-3ASR

SHELF

May 25, 2023

S-8

Form S-8 - Securities to be offered to employees in employee benefit plans

May 25, 2023

Proxies

TYPE

HEADLINE

FILED AT

DEFA14A

Form DEFA14A - Additional definitive proxy soliciting materials and Rule 14(a)(12) material

Apr 16, 2026

DEF 14A

Form DEF 14A - Other definitive proxy statements

Apr 16, 2026

PRE 14A

Form PRE 14A - Other preliminary proxy statements

Mar 30, 2026

DEFA14A

Form DEFA14A - Additional definitive proxy soliciting materials and Rule 14(a)(12) material

May 16, 2025

DEFA14A

Form DEFA14A - Additional definitive proxy soliciting materials and Rule 14(a)(12) material

Apr 8, 2025

DEF 14A

Form DEF 14A - Other definitive proxy statements

Apr 8, 2025

Ownerships

TYPE

HEADLINE

FILED AT

144

NEWForm 144 - Report of proposed sale of securities

Nov 9, 2026

Scott James R. Jr (Reporting)

Nov 3, 2026

144

Form 144 - Report of proposed sale of securities

Nov 2, 2026

144

Form 144 - Report of proposed sale of securities

Oct 30, 2026

Scott Jonathan R (Reporting)

Oct 26, 2026

Scott Jonathan R (Reporting)

Oct 23, 2026

Other

TYPE

HEADLINE

FILED AT

EFFECT

Form EFFECT - Notice of Effectiveness

Dec 17, 2021

CORRESP

Form CORRESP - Correspondence

Dec 14, 2021

LETTER

Form UPLOAD - SEC-generated letter

Nov 9, 2021

EFFECT

Form EFFECT - Notice of Effectiveness

Mar 24, 2020

EFFECT

Form EFFECT - Notice of Effectiveness

May 8, 2019

EFFECT

Form EFFECT - Notice of Effectiveness

May 8, 2019

First Interstate BancSystem, Inc. FIBK · SEC Filings