Biogen grants CLO Michael Parini 7,405 RSUs

Biogen’s Chief Legal Officer received a 7,405-unit RSU equity grant vesting annually over three years.

Rhea-AI Filing Summary

BIOGEN INC. (symbol: BIIB) is the issuer of record for a Form 4 filing submitted to the SEC. Parini Michael reported acquisition or exercise transactions in this Form 4 filing.

BIOGEN INC. (BIIB) reported that Chief Legal Officer Michael Parini received a grant of 7,405 Restricted Stock Units on September 1, 2026. The RSUs represent an equivalent number of shares of common stock and were awarded at a stated price of $0.00 per unit as an equity compensation award.

The RSUs vest in three equal yearly installments, beginning on the first anniversary of the grant date, September 1, 2026, and carry an expiration date of September 1, 2029. Following this grant, Parini holds 7,405 RSUs directly. No Rule 10b5-1 trading plan is reported for this award.

Insider Trade Summary

Grant/Award: 7,405 shares

Grant/Award 1 txn

Insider Parini Michael

Role Chief Legal Officer

Type	Security	Shares	Price	Value
Grant/Award	Restricted Stock Unit F1	7,405	$0.00	$0.00

Holdings After Transaction: Restricted Stock Unit — 7,405 contracts (Direct)

Footnotes (1)

1. F1. The restricted stock units vest in three equal yearly installments beginning on the first anniversary of the grant date of September 1, 2026.

Key Figures

RSUs granted: 7,405 units Stated grant price: $0.00 per unit Underlying common shares: 7,405 shares +3 more

6 metrics

RSUs granted 7,405 units Restricted Stock Units granted to Chief Legal Officer on September 1, 2026

Stated grant price $0.00 per unit Equity award grant price for 7,405 RSUs

Underlying common shares 7,405 shares Shares of Biogen common stock underlying the RSUs

Holdings after transaction 7,405 RSUs Total Restricted Stock Units held directly by Michael Parini after the grant

Vesting schedule 3 equal annual installments RSUs vest yearly beginning September 1, 2026

RSU expiration date September 1, 2029 Expiration date of the granted Restricted Stock Units

Key Terms

Restricted Stock Unit, vesting, expiration date, underlying security

4 terms

Restricted Stock Unit financial

"The RSUs are reported as a grant of Restricted Stock Unit"

A restricted stock unit is a promise from a company to give an employee shares of stock after certain conditions are met, like staying with the company for a set amount of time. It’s like earning a bonus that turns into company stock once you’ve proven your commitment, making it a way to motivate and reward employees.

vesting financial

"The restricted stock units vest in three equal yearly installments"

Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.

expiration date financial

"The RSUs carry an expiration date of September 1, 2029"

The expiration date is the deadline after which a financial contract, such as an option or a futures agreement, is no longer valid or can be exercised. It matters to investors because it determines the timeframe during which they can take action or benefit from the contract, similar to how a coupon or a food item has a limited period of usefulness. Once the expiration date passes, the contract loses its value or ability to be used.

underlying security financial

"The underlying security title is listed as Common Stock"

FAQ

What insider transaction did BIIB report for Michael Parini on this Form 4?

BIIB reported that Chief Legal Officer Michael Parini received a grant of 7,405 Restricted Stock Units on September 1, 2026, as an equity award tied to Biogen common stock, with no cash purchase price stated for the grant.

How many Biogen (BIIB) RSUs were granted to Michael Parini and at what price?

Michael Parini was granted 7,405 Restricted Stock Units relating to Biogen common stock at a stated price of $0.00 per unit, reflecting a compensation award rather than a market purchase.

What is the vesting schedule for Michael Parini’s new BIIB RSU grant?

The 7,405 RSUs granted to Michael Parini vest in three equal yearly installments, beginning on the first anniversary of the grant date, September 1, 2026, as disclosed in the footnote.

When do Michael Parini’s Biogen (BIIB) RSUs expire?

The Restricted Stock Units granted to Michael Parini carry an expiration date of September 1, 2029, as reported, with vesting occurring in three annual tranches starting in 2026.

How many Biogen (BIIB) RSUs does Michael Parini hold after this transaction?

Following the September 1, 2026 grant, Michael Parini is reported to hold 7,405 Restricted Stock Units directly, corresponding to an equivalent number of shares of Biogen common stock upon settlement, subject to vesting.

Was Michael Parini’s BIIB RSU grant made under a Rule 10b5-1 trading plan?

The filing indicates that no Rule 10b5-1 trading plan is reported for this RSU award, as the document-level checkbox for such a plan is not marked.

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

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Available on EDGAR 09/03/2026 - 04:21 PM Accepted by SEC EDGAR 09/03/2026 - 04:14 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^*

Parini Michael

(Last) (First) (Middle)

225 BINNEY STREET

(Street)

CAMBRIDGE MASSACHUSETTS 02142

(City) (State) (Zip)

UNITED STATES

(Country)

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 Legal Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/01/2026

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

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

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

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

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	09/01/2026		A		7,405		(1)	09/01/2029	Common Stock	7,405	$0	7,405	D

Explanation of Responses:

1. The restricted stock units vest in three equal yearly installments beginning on the first anniversary of the grant date of September 1, 2026.

	/s/ Bryan Keighery, attorney-in-fact for Mr. Parini	09/03/2026
	** 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.
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.
* Form 4: SEC 1474 (03-26)