X0508 4 2024-02-27 0001018399 ENTERPRISE BANCORP INC /MA/ EBTC 0001282759 ANSIN KEN S C/O ENTERPRISE BANCORP 222 MERRIMACK STREET LOWELL MA 01852 1 0 Common Stock 2024-02-27 4 S 0 120000 25.25 D 720802 I By Trust for Ronald M Ansin Family Members Common Stock 5506.5806 D Common Stock 151491 I By Trust Common Stock 177898 I By Trust for Ronald M Ansin Grandchildren Common Stock 6848 I By Trust for Son G. Ansin Common Stock 10051 I By Trust for Son K. Ansin Common Stock 2345 I By Wife The reporting person was appointed trustee of the Ronald M Ansin Trust on June 28, 2023. The reporting person and members of the family are among the beneficiaries of the trust. The reporting person disclaims beneficial ownership of the EBTC common stock held by the trust except to the extent of his pecuniary interest therein. Includes 42.778 shares acquired through dividend reinvestment on 9/1/2023. Includes 44.0067 shares acquired through dividend reinvestment on 12/1/2023. /s/ John P. Clancy, Jr. as attorney-in-fact for Ken S. Ansin 2024-02-29