X0203 3 2009-04-21 0 0001018399 ENTERPRISE BANCORP INC /MA/ EBTC 0001462721 Szablak Chester J JR C/O ENTERPRISE BANCORP, INC. 222 MERRIMACK STREET LOWELL MA 01852 0 1 0 0 EVP - Principal Subsidiary Common Stock 9947.4841 D Stock Option (Right to Buy) 9.11 2009-06-06 Common Stock 4000 D Stock Option (Right to Buy) 15.34 2010-12-31 Common Stock 4000 D Stock Option (Right to Buy) 14.375 2013-08-02 Common Stock 6500 D Stock Option (Right to Buy) 16.50 2014-03-06 Common Stock 3000 D Stock Option (Right to Buy) 12.75 2015-03-17 Common Stock 3500 D Stock Option (Right to Buy) 8.75 2016-03-16 Common Stock 2000 D Options vest at 25% per year on the anniversary of the grant date with the first installment vesting on 6/7/03. Options are fully vested. Options vest at 25% per year on the anniversary of the grant date with the first installment vesting on 1/2/05. Options are fully vested. Options vest at 25% per year on the anniversary of the grant date with the first installment vesting on 8/3/06. Options will be fully vested on 8/3/09. Options vest at 25% per year on the anniversary of the grant date with the first installment vesting on 3/7/08. Options will be fully vested on 3/7/11. Options vest at 25% per year on the anniversary of the grant date with the first installment vesting on 3/18/09. Options will be fully vested on 3/18/12. Options vest at 25% per year on the anniversary of the grant date with the first installment vesting on 3/17/10. Options will be fully vested on 3/17/13. /s/ Chester J. Szablak, Jr. 2009-04-30