X0508 4 2025-11-26 0 0001178670 ALNYLAM PHARMACEUTICALS, INC. ALNY 0001446125 Greenstreet Yvonne 675 WEST KENDALL STREET HENRI A. TERMEER SQUARE CAMBRIDGE MA 02142 1 1 0 0 Chief Executive Officer 0 Common Stock 2025-11-26 4 M 0 839 119.13 A 66248 D Common Stock 2025-11-26 4 M 0 2352 85.0 A 68600 D Common Stock 2025-11-26 4 M 0 847 118.05 A 69447 D Common Stock 2025-11-26 4 M 0 659 151.59 A 70106 D Common Stock 2025-11-26 4 F 0 1121 445.12 D 68985 D Common Stock 407 I by Managed Account Stock Option (right to buy) 85.0 2025-11-26 4 M 0 2352 0.0 D 2029-02-27 Common Stock 2352 0 D Stock Option (right to buy) 118.05 2025-11-26 4 M 0 847 0.0 D 2030-02-25 Common Stock 847 0 D Stock Option (right to buy) 119.13 2025-11-26 4 M 0 839 0.0 D 2028-02-28 Common Stock 839 0 D Stock Option (right to buy) 151.59 2025-11-26 4 M 0 659 0.0 D 2031-02-23 Common Stock 659 28141 D Reflects shares of ALNY common stock acquired by the Reporting Person under the issuer 401(k) plan as a result of the issuer 401(k) matching contribution program. This stock option was fully vested and exercisable as of February 28, 2023. This stock option was fully vested and exercisable as of February 26, 2024. This stock option was fully vested and exercisable as of December 1, 2021. This stock option was fully vested and exercisable as of February 24, 2025. By: Brett Budzinski, Attorney-in-Fact For: Yvonne Greenstreet 2025-12-01