X0306 4 2022-10-31 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 Common Stock 2022-10-31 4 S 0 7567 44.9246 D 1080953 D Common Stock 2022-10-31 4 S 0 7768 46.192 D 1073185 D Common Stock 2022-10-31 4 S 0 11756 46.8813 D 1061429 D Common Stock 2022-10-31 4 S 0 2909 47.8944 D 1058520 D Common Stock 2022-10-31 4 S 0 5008 44.9268 D 117992 I By John M. Evans, III 2018 Irrevocable Trust Common Stock 2022-10-31 4 S 0 4569 46.1882 D 113423 I By John M. Evans, III 2018 Irrevocable Trust Common Stock 2022-10-31 4 S 0 8235 46.9143 D 105188 I By John M. Evans, III 2018 Irrevocable Trust Common Stock 2022-10-31 4 S 0 2188 47.9143 D 103000 I By John M. Evans, III 2018 Irrevocable Trust The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan. The sale price reported is a weighted average price. The Reporting Person undertakes to provide to 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. These shares were sold in multiple transactions ranging from $44.48 to $45.445, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $45.57 to $46.56, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $46.57 to $47.52, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $47.68 to $48.17, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $44.48 to $45.445, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $45.57 to $46.56, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $46.57 to $47.555, inclusive. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $47.57 to $48.40, inclusive. By: /s/ Christine Bellon, Attorney-in-fact 2022-11-02