Transaction Details

Footnotes

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. | These shares are represented by restricted stock units (RSUs) granted under the Amended and Restated 2018 Stock Incentive Plan. Each RSU represents a contingent right to receive one share of common stock. | On February 27, 2023, the reporting person was granted 17,763 restricted stock units that vest ratably on each of the first, second and third anniversaries of the Grant Date. On February 27, 2026, the third and final tranche of restricted stock units from the February 27, 2023 grant vested and was released, as reported on this Form 4. | The restricted stock units vest ratably in three installments, with one third vesting on each of the first, second and third anniversaries of the grant date.