Form 4 Filing for ALNYLAM PHARMACEUTICALS, INC.

Olivier Brandicourt, a director at ALNYLAM PHARMACEUTICALS, INC., reported a transaction on May 20, 2026. The filing details the acquisition of 671 shares of Common Stock, represented by restricted stock units (RSUs) granted under the company's 2018 Stock Incentive Plan. These RSUs are subject to vesting conditions, with full vesting occurring on the first anniversary of the grant date or upon earlier retirement/resignation under specific circumstances. Additionally, Brandicourt acquired a stock option for 1441 shares of Common Stock, also subject to vesting on the first anniversary of the grant date or upon earlier retirement/resignation. The option has an exercise price of $298.48 and an expiration date of May 20, 2036. Following these transactions, Brandicourt directly holds 1446 shares of Common Stock and 1441 shares underlying the stock option.