BIOGEN INC. (BIIB) · Insider Trading (Form 4) SEC Filing

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-06-09 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: BIOGEN INC. (BIIB) CIK: 0000875045 --- Reporting Owner --- Name: Pangalos Menelas N CIK: 0002001873 Role: Director --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-06-09 | Code: M (Exercise of derivative) Shares: +2,370 | Price: $0.00 Shares Owned After: 2,370 | Ownership: D (Direct) [Transaction #2] Security: Common Stock Date: 2026-06-09 | Code: A (Grant or award) Shares: +1,505 | Price: $0.00 Shares Owned After: 3,875 | Ownership: D (Direct) Footnotes: [F1] The restricted stock units vest on the earlier of (i) the next annual meeting or (ii) the anniversary of the date of grant of June 9, 2026. --- Derivative Transactions --- [Transaction #1] Security: Restricted Stock Unit Date: 2026-06-09 | Code: M (Exercise of derivative) Shares: -2,370 | Price: $0.00 Exercisable: N/A | Expires: 2026-06-17 Shares Owned After: 0 | Ownership: D (Direct) Footnotes: [F2] The restricted stock units vest on the earlier of (i) the next annual meeting or (ii) the anniversary of the date of grant of June 17, 2025. --- Footnotes (Complete Index) --- F1: The restricted stock units vest on the earlier of (i) the next annual meeting or (ii) the anniversary of the date of grant of June 9, 2026. F2: The restricted stock units vest on the earlier of (i) the next annual meeting or (ii) the anniversary of the date of grant of June 17, 2025. --- Signature --- /s/ /s/ Wendell Taylor, attorney-in-fact for Dr. Pangalos (2026-06-11)