X0306 4 2022-03-15 0001018399 ENTERPRISE BANCORP INC /MA/ EBTC 0001282759 ANSIN KEN S C/O ENTERPRISE BANCORP 222 MERRIMACK STREET LOWELL MA 01852 1 Common Stock 2022-03-15 4 A 0 519 0 A 4602.6759 D Common Stock 151491 I By Trust Common Stock 177898 I By Trust for Ronald M Ansin Grandchildren Common Stock 5848 I By Trust for Son G. Ansin Common Stock 9051 I By Trust for Son K. Ansin Common Stock 2345 I By Wife Includes 21.2796 shares acquired through dividend reinvestment on 6/1/2021. Includes 22.0261 shares acquired through dividend reinvestment on 9/1/2021. Includes 19.5529 shares acquired through dividend reinvestment on 12/1/2021. Includes 21.4297 shares acquired through dividend reinvestment on 3/1/2022. /s/ John P. Clancy, Jr. as attorney-in-fact for Ken S. Ansin 2022-03-17