0001521951 2026-05-22 2026-05-22 false 0001521951 8-K 2026-05-22 First Business Financial Services, Inc. WI 001-34095 39-1576570 401 Charmany Drive Madison WI 53719 608 238-8008 false false false false Common Stock, $0.01 par value FBIZ NASDAQ false