Adam Keeney - 01 May 2025 Form 4 Insider Report for BIOGEN INC. (BIIB)

Role: Head of Corporate Development
Signature: /s/ Samuel Ntonme, attorney-in-fact for Mr. Keeney
Issuer symbol: BIIB
Transactions as of: 01 May 2025
Net transactions value: -$54,902
Form type: 4
Filing time: 05 May 2025, 16:19:20 UTC
Previous filing: 10 Feb 2025
Next filing: 10 Feb 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Keeney Adam	Head of Corporate Development	BIOGEN INC., 225 BINNEY STREET, CAMBRIDGE	/s/ Samuel Ntonme, attorney-in-fact for Mr. Keeney	05 May 2025	0001973607

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	BIIB	Common Stock	Options Exercise	$0	+938	+49%	$0.000000	2,838	01 May 2025	Direct
transaction	BIIB	Common Stock	Tax liability	$54,902	-454	-16%	$120.93	2,384	01 May 2025	Direct

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	BIIB	Restricted Stock Unit	Options Exercise	$0	-938	-50%	$0.000000	939	01 May 2025	Common Stock	938	$0.000000	Direct	F1

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The restricted stock units vest in three equal yearly installments beginning on the first anniversary of the grant date of May 1, 2023.