FIRST INTERSTATE BANCSYSTEM INC — Form 10-Q

First Interstate BancSystem, Inc. amended and restated its Deferred Compensation Plan effective February 15, 2025 (restated May 13, 2026). The plan covers selected management and highly compensated employees and directors. Key provisions: participants may defer salary/bonus (1–100% in 1% increments); employer provides discretionary matching and other contributions; vesting of employer contributions occurs at 2 years of service (100%); distributions permitted upon specified date, separation from service, retirement (age 65+), disability, death, or change in control, with a required 6-month delay for key employees of publicly traded companies; plan is unfunded with accounts invested in participant-selected options; IRC §409A compliant. No specific dollar amounts, participant count, or plan asset values disclosed in this amendment document.