X0407 4 2023-01-31 0 0001745999 Beam Therapeutics Inc. BEAM 0001786304 Evans John M. C/O BEAM THERAPEUTICS INC., 238 MAIN STREET CAMBRIDGE MA 02142 1 1 0 0 CEO 0 Common Stock 2023-03-06 4 L 0 225 0.00 A 1059053 D Common Stock 2023-03-31 4 A 0 56250 0.00 A 1115303 D Common Stock 2023-03-31 4 M 0 13850 7.22 A 1129153 D Common Stock 103000 I By John M. Evans, III 2018 Irrevocable Trust Stock Option (Right to Buy) 43.45 2023-01-31 4 A 0 112500 0.00 A 2033-01-31 Common Stock 112500 112500 D Stock Option (Right to Buy) 7.22 2023-03-31 4 M 0 13850 0.00 D 2029-05-17 Common Stock 13850 196904 D Distribution of Beam Therapeutics Inc. ("BEAM") common stock held by ARCH Venture Fund IX, L.P. to its partners for no consideration. Includes 308 shares and acquired by the Reporting Person under the BEAM Amended and Restated 2019 Employee Stock Purchase Plan on September 30, 2022. Represents restricted stock units ("RSUs") granted to the Reporting Person under BEAM's 2019 Equity Incentive Plan. Each RSU represents the contingent right to receive one share of the BEAM's common stock. The RSUs vest in four substantially equal annual installments on each of the first four anniversaries of the date of grant, subject to the Reporting Person's continued service with BEAM through each vesting date. This stock option vests in equal monthly installments each month following the date of grant for the subsequent 48 months, subject to the reporting person's continued service with BEAM through each vesting date. This stock option vests as to 25% on the first anniversary of the vesting commencement date, October 1, 2019, and at a rate of 2.78% each month thereafter until the option is fully vested. . By: /s/ Christine Bellon, Attorney-in-fact 2023-03-31