X0508 4 2024-02-16 0000875045 BIOGEN INC. BIIB 0001910644 Murphy Nicole 225 BINNEY STREET CAMBRIDGE MA 02142 1 Head of Pharm Ops and Tech 0 Common Stock 2024-02-16 4 M 0 856 0 A 9623.9895 D Common Stock 2024-02-16 4 F 0 414 219.08 D 9209.9895 D Common Stock 2024-02-16 4 M 0 404 0 A 9613.9895 D Common Stock 2024-02-16 4 F 0 196 219.08 D 9417.9895 D Performance Stock Unit 0 2024-02-16 4 M 0 856 0 D 2024-02-18 2024-02-18 Common Stock 856 0 D Restricted Stock Unit 0 2024-02-16 4 M 0 404 0 D 2024-02-18 Common Stock 404 504 D Restricted Stock Unit 0 2024-02-16 4 J 0 504 0 D 2024-02-18 Common Stock 504 0 D This award was granted to the reporting person on February 18, 2021. The number of RSUs reported represents the maximum possible number of shares that are eligible for vesting, which is 200% of the number of shares at target payout. One-third of these RSUs are eligible to vest on each of the first three anniversaries of the grant date. The actual number of shares that will vest on each vesting date will be determined by comparing the price of Biogen common stock on such vesting date to the price on the grant date (i.e., number of vested shares = number of shares at target payout times [the 30-day average closing stock price ending on the vesting date divided by the 30-day average closing stock price following and including the grant date]). This represents the difference between the maximum possible number of shares that were eligible for vesting and the actual number that vested. /s/ Wendell Taylor, attorney in fact for Nicole Murphy 2024-02-21