First Interstate BancSystem, Inc. operates as the bank holding company for First Interstate Bank that provides a range of banking products and services in the United States. The company offers various traditional depository products, including checking, savings, and time deposits; and repurchase agreements primarily for commercial and municipal depositors. It also provides a range of trust, employee benefit, investment management, insurance, agency, and custodial services, including administration of estates and personal trusts; manages investment accounts for individuals; offers employee benefit plans and charitable foundations; and provides insurance planning.