Form 3 Filing for Jolyn M. Kanning - Ownership of FIBK Common Stock

This filing reports the initial ownership of First Interstate BancSystem Inc. (FIBK) common stock by Jolyn M. Kanning, identified by CIK 0002129553. Ms. Kanning, who holds the position of Chief Risk Officer, directly owns 11,638 shares of common stock. This number includes 3,305 unvested restricted stock units, each convertible to one share upon vesting. Additionally, she indirectly holds 784 shares through a 401k plan. The filing is executed by Kirk D. Jensen as Attorney-in-Fact for Ms. Kanning, with the report dated April 29, 2026.