Form 4 Filing for Margaret A. Hamburg

This filing details transactions made by Margaret A. Hamburg, a director at ALNYLAM PHARMACEUTICALS, INC., on May 20, 2026. Hamburg acquired 671 shares of Common Stock and was granted a Stock Option (Right to Buy) for 1441 shares. The Common Stock acquisition, represented by restricted stock units (RSUs) under the 2018 Stock Incentive Plan, vests fully on the first anniversary of the grant date or earlier upon retirement/resignation within 90 days of the anniversary. The stock option also vests fully under similar conditions. Both transactions are marked as direct ownership and acquired, with a transaction price of $0.00 per share. Post-transaction, Hamburg directly owns 1582 shares of Common Stock and holds 1441 shares through the stock option.