Biogen Acquisition Triggers Apellis Removal from S&P SmallCap 600 on May 14
BIIB•Biogen Inc will acquire Apellis Pharmaceuticals in a pending transaction expected to close soon, prompting Apellis’s removal from the S&P SmallCap 600 on May 14, 2026. Remitly Global will replace Apellis in the index, alongside Bright Horizons’ addition and Tri Pointe Homes’ deletion.
1. Biogen to Acquire Apellis Pharmaceuticals
Biogen Inc, a member of the S&P 500, is purchasing Apellis Pharmaceuticals in a deal expected to close soon pending final conditions. This transaction expands Biogen’s pipeline with Apellis’s complement inhibitor therapies and underscores its commitment to dermatology and rare disease treatment.
2. Index Reconstitution Details
Effective May 14, 2026, Apellis will be deleted from the S&P SmallCap 600 due to the acquisition, with Remitly Global joining the index in its place. Bright Horizons Family Solutions will also be added to the SmallCap 600, replacing Tri Pointe Homes as part of the routine index rebalancing.
