X0508 4 2025-11-17 0 0001178670 ALNYLAM PHARMACEUTICALS, INC. ALNY 0001886431 Fitzgerald Kevin Joseph 675 WEST KENDALL STREET HENRI A. TERMEER SQUARE CAMBRIDGE MA 02142 0 1 0 0 CSO & EVP, Head of Research 1 Common Stock 2025-11-17 4 M 0 8161 119.13 A 33392 D Common Stock 2025-11-17 4 S 0 8168 449.0 D 25224 D Common Stock 2025-11-17 4 S 0 96 450.09 D 25128 D Common Stock 2025-11-17 4 S 0 129 451.51 D 24999 D Common Stock 2025-11-17 4 S 0 368 455.24 D 24631 D Common Stock 2025-11-17 4 S 0 364 456.25 D 24267 D Common Stock 2025-11-17 4 S 0 262 457.39 D 24005 D Common Stock 2025-11-17 4 S 0 794 458.41 D 23211 D Common Stock 2025-11-17 4 S 0 622 459.89 D 22589 D Common Stock 2025-11-17 4 S 0 707 460.84 D 21882 D Common Stock 2025-11-17 4 S 0 323 461.96 D 21559 D Common Stock 2025-11-17 4 S 0 295 463.08 D 21264 D Common Stock 537 I by Managed Account Stock Option (right to buy) 119.13 2025-11-17 4 M 0 8161 0.0 D 2028-03-01 Common Stock 8161 839 D This transaction was made pursuant to a Rule 10b5-1 (c) trading plan adopted by the Reporting Person on August 14, 2025. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $451.41 to $451.84. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $454.92 to $455.45. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $455.97 to $456.94. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $457.00 to $457.98. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $458.01 to $458.94. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $459.40 to $460.36. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $460.46 to $461.40. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $461.50 to $462.39. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. The price reported represents the weighted average sales price of shares sold in multiple transactions at prices ranging from $462.82 to $463.46. The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. 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 December 1, 2021. By: Brett Budzinski, Attorney-in-Fact For: Kevin Fitzgerald 2025-11-19