144 0001198518 XXXXXXXX LIVE 0000860413 FIRST INTERSTATE BANCSYSTEM, INC. 001-34653 401 North 31st Street Billings MT 59101 (406) 255-5311 QUINN T HEYNEMAN Director's son Common Morgan Stanley Smith Barney LLC Executive Financial Services

1 New York Plaza 8th Floor New York NY 10004

615 23142.45 102890614 02/03/2026 NASDAQ Common 08/24/2016 Gift from Affiliate John Heyneman Jr Y 08/24/2016 211 NA Common 09/08/2016 Gift from Affiliate John Heyneman Y 09/08/2016 404 NA N Bench Ranch LLC

401 North 31st Street Billings MT 59101

Common 11/11/2025 15000 482162.50 AWE' LLC

401 North 31st Street Billings MT 59101

Common 11/10/2025 20000 641298.00 02/03/2026 /s/ John M Heyneman Jr