Biogen CEO reports RSU vesting and share withholding

Biogen Inc. President and CEO Christopher Viehbacher reported multiple equity transactions on February 6, 2026 as restricted stock units converted into common shares and a portion of the new shares was withheld for taxes.

Rhea-AI Filing Summary

Biogen Inc. President and CEO Christopher Viehbacher reported multiple equity transactions on February 6, 2026 as restricted stock units converted into common shares and a portion of the new shares was withheld for taxes.

He acquired 9,008 and 15,453 shares of Biogen common stock at an exercise price of $0 through the vesting and settlement of previously granted restricted stock units. To satisfy tax obligations tied to these vestings, 4,356 shares and 6,624 shares were automatically withheld at a price of $201.18 per share. After these transactions, he directly owned 29,924 shares of common stock, along with 9,009 and 30,907 restricted stock units that continue to vest in three equal annual installments from their respective 2024 and 2025 grant dates.

Insider Trade Summary

24,461 shares exercised/converted

Exercise 6 txns

Insider Viehbacher Christopher

Role President and CEO

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Unit	9,008	$0.00	$0.00
Exercise	Restricted Stock Unit	15,453	$0.00	$0.00
Exercise	Common Stock	9,008	$0.00	$0.00
Exercise Price or Tax Liability	Common Stock	4,356	$201.18	$876K
Exercise	Common Stock	15,453	$0.00	$0.00
Exercise Price or Tax Liability	Common Stock	6,624	$201.18	$1.33M

Holdings After Transaction: Restricted Stock Unit — 39,916 contracts (Direct); Common Stock — 29,924 shares (Direct)

Footnotes (2)

1. F1. The restricted stock units vest in three (3) equal annual installments, commencing one year after the grant date of 02/07/2024.
2. F2. The restricted stock units vest in three equal yearly installments beginning on the first anniversary of the grant date of February 6, 2025.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transactions did Biogen (BIIB) report for CEO Christopher Viehbacher?

Biogen reported that CEO Christopher Viehbacher had restricted stock units convert into common stock on February 6, 2026. He acquired shares at a $0 exercise price and had some shares withheld at $201.18 per share to cover tax obligations tied to the vesting.

How many Biogen (BIIB) shares does the CEO own after the February 6, 2026 Form 4?

After the reported transactions, Christopher Viehbacher directly owned 29,924 shares of Biogen common stock. This reflects new shares from vested restricted stock units, net of shares withheld to pay taxes, as disclosed in the Form 4 insider filing.

What does the transaction code M mean in the Biogen (BIIB) Form 4 filing?

In this filing, code M shows the conversion of restricted stock units into Biogen common stock at a $0 exercise price on February 6, 2026. These are equity awards settling into shares rather than open-market purchases or sales by the CEO.

Why were some Biogen (BIIB) shares sold or withheld at $201.18 for the CEO?

Shares marked with transaction code F at $201.18 per share were withheld to satisfy tax withholding obligations from the vesting of restricted stock units. This is a common administrative step when equity awards convert into taxable shares.

How many restricted stock units does the Biogen (BIIB) CEO still hold after these transactions?

Following the February 6, 2026 activity, Christopher Viehbacher held 9,009 and 30,907 restricted stock units. These units are scheduled to vest in three equal annual installments from grant dates in February 2024 and February 2025, as noted in the footnotes.

How do the Biogen (BIIB) CEO’s restricted stock units vest over time?

One restricted stock unit grant vests in three equal annual installments starting one year after February 7, 2024. A second grant vests in three equal yearly installments beginning on the first anniversary of the February 6, 2025 grant date, subject to continued service.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 02/10/2026 - 05:06 PM Learn about SEC filing dates

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^*

Viehbacher Christopher

(Last) (First) (Middle)

BIOGEN INC.

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)

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

3. Date of Earliest Transaction (Month/Day/Year)
02/06/2026

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	02/06/2026		M		9,008	A	$0	25,451	D
Common Stock	02/06/2026		F		4,356	D	$201.18	21,095	D
Common Stock	02/06/2026		M		15,453	A	$0	36,548	D
Common Stock	02/06/2026		F		6,624	D	$201.18	29,924	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	02/06/2026		M			9,008	(1)	02/07/2027	Common Stock	9,008	$0	9,009	D
Restricted Stock Unit	$0	02/06/2026		M			15,453	(2)	02/06/2028	Common Stock	15,453	$0	30,907	D

Explanation of Responses:

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

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

	/s/ Wendell Taylor, attorney-in-fact for Christopher A. Viehbacher	02/10/2026
	** 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.
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