[Form 4] Biogen Inc. Insider Trading Activity

Rhea-AI Filing Summary

Biogen Inc. (BIIB) Director Caroline Dorsa reported acquiring 3,160 shares of Common Stock on June 17, 2025. The shares were awarded at a price of $0, suggesting this was a stock grant as part of director compensation.

Following this transaction, Dorsa now beneficially owns a total of 31,002 shares directly. The filing indicates this was a straightforward acquisition with no derivative securities involved in the transaction.

The Form 4 was signed by Wendell Taylor as attorney-in-fact for Caroline Dorsa on June 18, 2025, within the required reporting timeline. This transaction appears to be part of regular director compensation practices rather than open market trading activity.

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^*

DORSA CAROLINE

(Last) (First) (Middle)

BIOGEN INC.

225 BINNEY STREET

(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)

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

3. Date of Earliest Transaction (Month/Day/Year)
06/17/2025

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	06/17/2025		A		3,160	A	$0	31,002	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

Explanation of Responses:

	/s/ Wendell Taylor, Attorney in Fact for Caroline D. Dorsa	06/18/2025
	** 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

How many BIIB shares did Caroline Dorsa acquire on June 17, 2025?

According to the Form 4 filing, Caroline Dorsa acquired 3,160 shares of Biogen (BIIB) common stock on June 17, 2025 at a price of $0, suggesting these were granted shares.

What is Caroline Dorsa's total BIIB stock ownership after the June 2025 transaction?

Following the reported transaction, Caroline Dorsa beneficially owns 31,002 shares of Biogen (BIIB) common stock directly (indicated by 'D' under ownership form).

What is Caroline Dorsa's role at BIIB according to the Form 4?

According to the Form 4 filing, Caroline Dorsa serves as a Director of Biogen Inc. (BIIB), as indicated by the 'X' marked in the Director box under Section 5 of the form.

When was the Form 4 for BIIB insider trading signed?

The Form 4 was signed on June 18, 2025 by Wendell Taylor, serving as Attorney in Fact for Caroline D. Dorsa, one day after the reported transaction date.

Did BIIB director Caroline Dorsa purchase or receive these shares?

Caroline Dorsa received these shares as an acquisition ('A' transaction code) at a price of $0, indicating they were granted to her rather than purchased on the open market, likely as part of director compensation.