X0609 4 2026-10-05 0 0000860413 FIRST INTERSTATE BANCSYSTEM INC FIBK 0001198533 SCOTT JAMES R false P O BOX 7113 BILLINGS MT 59103 0 0 1 0 0001908712 James R Scott Trust, James R Scott & First Interstate Wealth Management Co-TTEEs false P O BOX 7113 BILLINGS MT 59103 0 0 1 0 0 Common Stock 2026-10-05 4 G 0 6990 0 D 2038296 I See Footnote Composed of 1,982,892 shares held of record by James R Scott Trust, James R Scott & First Interstate Wealth Management Co-TTEEs, 14,534 shares held of record by James R Scott's 401(k) plan, and 40,870 shares held of record by James R. Scott's spouse. As a result of agreements entered into among the reporting persons, the issuer, and other stockholders of the issuer signatory thereto, the reporting persons may be deemed members of a group with the other signatories thereto and may be deemed to share beneficial ownership of the securities reported therein. Each of the reporting persons disclaims beneficial ownership of any such securities, except to the extent of his or its pecuniary interest therein. The reporting persons expect to file future Forms 4 or 5, if any, together with James R. Scott with the indication of direct or indirect ownership in Tables I and II being made from James R. Scott's perspective, unless expressly noted otherwise by footnote. JAMES R SCOTT, By: ++ 2026-10-06 James R Scott Trust, James R Scott & First Interstate Wealth Management Co-TTEEs, By: ++ 2026-10-06 ++ /s/ Timothy Leuthold, Attorney-in-Fact for Reporting Person 2026-10-06