First Interstate BancSystem(FIBK) - 2023 Q4 - Annual Report

Washington D.C. 20549 (Mark One) ☑ Annual Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the fiscal year ended December 31, 2023 or ☐ Transition Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the transition period from to . Commission File Number: 001-34653 (Exact name of registrant as specified in its charter) Delaware 81-0331430 (State or other jurisdiction of incorporation or organization) (IRS Employer Identification No.) | --- | --- ...