[Form 4] BIOGEN INC. Insider Trading Activity

Rhea-AI Filing Summary

Sean Godbout, identified as a Director and the issuer's Chief Accounting Officer, reported changes in his beneficial ownership of BioGen Inc. (BIIB) on 10/02/2025. He had restricted stock units (RSUs) vest that resulted in an acquisition of 502.6667 shares at no cash cost (code M), and on the same date he disposed of 8 shares by sale at $155.25 (code F), leaving him with 494.6667 shares reported as beneficially owned. The RSUs were granted on 10/02/2023 and vest in three equal annual installments beginning one year after the grant date; the filing was signed by an attorney-in-fact on 10/06/2025.

Positive

• RSU vesting converted to 502.6667 shares at no cash cost, reflecting compensation realization
• Disclosure filed and signed (via attorney-in-fact), showing timely reporting of insider activity

Negative

• Sale of 8 shares at $155.25 reduced holdings to 494.6667 shares

Insights

Insider Transactions & Compliance Analyst

TL;DR: Officer reported RSU vesting and a small sale on 10/02/2025.

The reporting shows a non-cash vesting event of restricted stock units converting into 502.6667 shares (transaction code M), consistent with scheduled vesting rather than a market purchase. A contemporaneous sale of 8 shares at $155.25 (code F) reduced the post-transaction holdings to 494.6667 shares.

These entries align with routine compensation vesting and a minor disposition; compliance considerations include whether the sale complied with any pre-established trading plan. Monitor any future Form 4s for additional sales or large off-cycle dispositions within the next 12 months.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Godbout Sean

(Last) (First) (Middle)

225 BINNEY

(Street)

CAMBRIDGE MA 02142

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
BIOGEN INC. [ BIIB ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Accounting Officer

3. Date of Earliest Transaction (Month/Day/Year)
10/02/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	10/02/2025		M		26	A	$0	502.6667	D
Common Stock	10/02/2025		F		8	D	$155.25	494.6667	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Unit	$0	10/02/2025		M			26	(1)	10/02/2026	Common Stock	26	$0	27	D

Explanation of Responses:

1. The restricted stock units vest in three (3) equal annual installments commencing one year after the grant date of 10/02/2023.

	/s/ Wendell Taylor, attorney-in-fact for Mr. Godbout	10/06/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did the BIIB Form 4 filed by Sean Godbout report?

The form reports vesting of 502.6667 RSU-derived shares and a sale of 8 shares at $155.25 on 10/02/2025, leaving 494.6667 shares beneficially owned.

What is the nature of the securities that vested for BIIB insider Sean Godbout?

The vested securities were restricted stock units (RSUs) granted on 10/02/2023 that vest in three equal annual installments starting one year after the grant date.

How many shares does Sean Godbout beneficially own after the reported transactions?

After the reported transactions on 10/02/2025, he beneficially owns 494.6667 shares.

At what price were the sold shares transacted?

The sale recorded on 10/02/2025 lists a disposal of 8 shares at $155.25.

Who signed the Form 4 for Sean Godbout and when?

The Form 4 was signed by Wendell Taylor, attorney-in-fact for Mr. Godbout on 10/06/2025.