BILLINGS, Mont.–(BUSINESS WIRE)–First Interstate BancSystem, Inc. (NASDAQ: FIBK) has been assigned a senior unsecured debt rating of BBB+ by Kroll Bond Rating Agency (KBRA). Its banking subsidiary, First Interstate Bank, received a deposit and senior unsecured debt rating of A-. KBRA described First Interstate’s rating outlook as stable. According to KBRA, the ratings for First Interstate BancSystem are supported by the Company’s steady overall performance, including stable returns, a solid l
