0000790359 2026-05-18 2026-05-18 false 0000790359 8-K 2026-05-18 NBT BANCORP INC. DE 000-14703 16-1268674 52 South Broad Street Norwich NY 13815 607 337-2265 false false false false Common Stock, par value $0.01 per share NBTB NASDAQ false