X0306 4 2023-01-26 0 0001745999 Beam Therapeutics Inc. BEAM 0001786484 Burrell Terry-Ann C/O BEAM THERAPEUTICS INC., 238 MAIN STREET CAMBRIDGE MA 02142 0 1 0 0 Chief Financial Officer Common Stock 2023-01-26 4 M 0 1102 13.68 A 32379 D Common Stock 2023-01-26 4 S 0 1102 45.1572 D 31277 D Common Stock 2023-01-27 4 M 0 36152 13.68 A 67429 D Common Stock 2023-01-27 4 S 0 36152 45.0804 D 31277 D Stock Option (Right to Buy) 13.68 2023-01-26 4 M 0 1102 0.00 D 2029-08-31 Common Stock 1102 221717 D Stock Option (Right to Buy) 13.68 2023-01-27 4 M 0 36152 0.00 D 2029-08-31 Common Stock 36152 185565 D The stock option exercises reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $45.00 to $45.48, inclusive. The Reporting Person undertakes to provide Beam Therapeutics Inc. ("BEAM"), any security holder of BEAM or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $45.00 to $45.24, inclusive. The Reporting Person undertakes to provide BEAM, any security holder of BEAM or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range. The option vested as to 25% on the first anniversary of the of the vesting commencement date, August 20, 2019, and continues to vest at a rate of 2.78% each month thereafter until the option is fully vested. By: /s/ Christine Bellon, Attorney-in-fact 2023-01-30