144 0001198518 XXXXXXXX LIVE 0000860413 FIRST INTERSTATE BANCSYSTEM INC. 001-34653 401 North 31st Street Billings MT 59101 (406) 255-5311 BENCH RANCH LLC Director Common Morgan Stanley Smith Barney LLC Executive Financial Services

1 New York Plaza 8th Floor New York NY 10004

15000 482169.00 102890614 11/11/2025 NASDAQ Common 12/04/2024 Distribution from a Trust or an Estate Susan S Heyneman N 15000 01/02/1976 Stock Swap N AWE' LLC

401 North 31st Street Billings MT 59101

Common 11/10/2025 20000 641298.00 Sales that were executed on November 11, 2025 are being reported on this Form 144 filed on November 12, 2025 given the EDGAR system was not accepting filings on November 11, 2025 in observance of the federal holiday. 11/12/2025 /s/ John M Heyneman Jr