X0508 4 2024-03-06 0001492422 Apellis Pharmaceuticals, Inc. APLS 0001657719 Watson David O. C/O APELLIS PHARMACEUTICALS, INC 100 FIFTH AVENUE, 3RD FLOOR WALTHAM MA 02451 1 General Counsel 0 Common Stock 2024-03-06 4 M 0 3762 13.85 A 107152 D Common Stock 3333 I Indirect Owner (Custodial Account for Son) Common Stock 80705 I Indirect Owner (The David O. Watson Irrevocable Trust of 2023) Common Stock 6667 I Indirect Owner (The Watson Education Trust) Stock Option (Right to Buy) 13.85 2024-03-06 4 M 0 3762 0 D 2029-02-07 Common Stock 3762 0 D This represents a custodial account held by the reporting person for the sole benefit of his minor son. The securities are held by The David O. Watson Irrevocable Trust of 2023. William Zorn is the trustee of The David O. Watson Irrevocable Trust of 2023. The reporting person disclaims beneficial ownership over the shares held by The David O. Watson Irrevocable Trust of 2023 except to the extent of his pecuniary interest therein. The securities are held by The Watson Education Trust (the "Trust"), for which the reporting person serves as trustee. The reporting person disclaims beneficial ownership over the shares held by the Trust except to the extent of his pecuniary interest therein. This option was granted on February 8, 2019 and is fully vested. David Watson 2024-03-08