First Interstate BancSystem Announces Director Retirements
Billings, MT – March 19, 2025 – First Interstate BancSystem, Inc. (NASDAQ: FIBK) announced the upcoming retirements of Thomas E. Henning and Frances P. Grieb from its Board of Directors.

Thomas E. Henning, a Class II director, will step down at the 2025 annual meeting in accordance with the company's retirement policy at age 72.
Frances P. Grieb, a Class I director, has decided not to seek re-election and will also retire at the 2025 annual meeting.
Both directors joined the board following First Interstate’s 2022 acquisition of Great Western Bancorp, Inc. and will continue serving until their retirements. The company expressed gratitude for their contributions.