BIOGEN INC. - Director's Dealing 2026

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: BIOGEN INC. (BIIB)
CIK: 0000875045
Period of Report: 2026-02-06

Reporting Person: Murphy Nicole (Head of Pharm Ops and Tech)

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2026-02-06	Common Stock	M	2102	—	Acquired	16324.0408	Direct
2026-02-06	Common Stock	F	1017	$201.18	Disposed	15307.0408	Direct
2026-02-06	Common Stock	M	1940	—	Acquired	17247.0408	Direct
2026-02-06	Common Stock	F	914	$201.18	Disposed	16333.0408	Direct
2026-02-06	Common Stock	M	4683	—	Acquired	21016.0408	Direct
2026-02-06	Common Stock	F	1408	$201.18	Disposed	19608.0408	Direct

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2026-02-06	Restricted Stock Unit	$0	M	2102	Disposed	2026-02-08	Common Stock (2102)	Direct
2026-02-06	Restricted Stock Unit	$0	M	1940	Disposed	2027-02-07	Common Stock (1940)	Direct
2026-02-06	Restricted Stock Unit	$0	M	4683	Disposed	2028-02-06	Common Stock (4683)	Direct

F1: Includes 166.6667 shares acquired under the Biogen Inc. employee stock purchase plan on 3/31/2025.

F2: The restricted stock units vest in three (3) equal annual installments commencing one year after the grant date of 02/8/2023.

F3: The restricted stock units vest in three (3) equal annual installments, commencing one year after the grant date of 02/07/2024.

F4: The restricted stock units vest in three equal yearly installments beginning on the first anniversary of the grant date of February 6, 2025.