FMR and Abigail Johnson disclose 6.4% Biogen (BIIB) ownership stake

Rhea-AI Filing Summary

FMR LLC and Abigail P. Johnson report significant ownership of Biogen Inc.12/31/2025, they beneficially owned 9,413,062.03 shares, representing 6.4% of the class.

FMR LLC held sole voting power over 8,291,794.64 shares and sole dispositive power over 9,413,062.03 shares

Insights

Equity ownership and governance analyst

FMR and Abigail Johnson disclose a 6.4% passive stake in Biogen.

FMR LLC and Abigail P. Johnson report beneficial ownership of 9,413,062.03 Biogen common shares, equal to 6.4% of the class as of 12/31/2025. This establishes them as sizable shareholders with notable influence potential through voting, especially via FMR’s institutional platforms.

FMR has sole voting power over 8,291,794.64 shares and sole dispositive power over the full 9,413,062.03 shares, while Abigail Johnson has sole dispositive but no voting power. The certification explicitly states the position is held in the ordinary course of business and not to change or influence control.

The disclosure also notes that other underlying clients may receive dividends or sale proceeds, with no single other person exceeding five percent of Biogen’s outstanding common stock. Future ownership updates, if any, would appear in subsequent beneficial ownership reports.

02/05/2026 - 01:16 PM

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

BIOGEN INC

(Name of Issuer)

COMMON STOCK

(Title of Class of Securities)

09062X103

(CUSIP Number)

12/31/2025

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP No. 09062X103

1

Names of Reporting Persons

FMR LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 8,291,794.64
6	Shared Voting Power 0.00
7	Sole Dispositive Power 9,413,062.03
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

9,413,062.03

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

6.4 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

CUSIP No. 09062X103

1

Names of Reporting Persons

Abigail P. Johnson

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 9,413,062.03
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

9,413,062.03

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

6.4 %

12

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: BIOGEN INC
(b)	Address of issuer's principal executive offices: 225 BINNEY STREET,Cambridge,MA,USA,02142
Item 2.
(a)	Name of person filing: FMR LLC
(b)	Address or principal business office or, if none, residence: 245 Summer Street, Boston, Massachusetts 02210
(c)	Citizenship: Not applicable
(d)	Title of class of securities: COMMON STOCK
(e)	CUSIP No.: 09062X103
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 9413062.03
(b)	Percent of class: 6.4 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: Please see the responses to Items 5 and 6 on the cover page.
	(ii) Shared power to vote or to direct the vote: 0.00
	(iii) Sole power to dispose or to direct the disposition of: 9413062.03
	(iv) Shared power to dispose or to direct the disposition of: 0.00
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. One or more other persons are known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the COMMON STOCK of BIOGEN INC. No one other person's interest in the COMMON STOCK of BIOGEN INC is more than five percent of the total outstanding COMMON STOCK.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. See attached Exhibit 99.
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

FMR LLC

Signature:	Stephanie J. Brown
Name/Title:	Duly authorized under Power of Attorney effective as of January 3, 2023, by and on behalf of FMR LLC and its direct and indirect subsidiaries*
Date:	02/04/2026

Abigail P. Johnson

Signature:	Stephanie J. Brown
Name/Title:	Duly authorized under Power of Attorney effective as of January 26, 2023, by and on behalf of Abigail P. Johnson**
Date:	02/04/2026

Comments accompanying signature: * This power of attorney is incorporated herein by reference to Exhibit 24 to the Schedule 13G filed by FMR LLC on January 10, 2023, accession number: 0000315066-23-000003. ** This power of attorney is incorporated herein by reference to Exhibit 24 to the Schedule 13G filed by FMR LLC on January 31, 2023, accession number: 0000315066-23-000038.

Exhibit Information

Please see Exhibit 99 for 13d-1(k) (1) agreement.

FAQ

How many Biogen (BIIB) shares does FMR LLC report owning in this Schedule 13G?

FMR LLC reports beneficial ownership of 9,413,062.03 Biogen common shares. This stake represents 6.4% of the company’s outstanding common stock as of December 31, 2025, making FMR a significant institutional shareholder in Biogen.

What percentage of Biogen (BIIB) does FMR LLC and Abigail P. Johnson beneficially own?

The filing states that FMR LLC and Abigail P. Johnson beneficially own 6.4% of Biogen’s common stock. This corresponds to 9,413,062.03 shares as of December 31, 2025, giving them a sizeable but minority ownership position in the company.

Who are the reporting persons in this Biogen (BIIB) Schedule 13G filing?

The reporting persons are FMR LLC, organized in Delaware, and Abigail P. Johnson, a United States citizen. Both report beneficial ownership of the same 9,413,062.03 Biogen common shares, equal to 6.4% of the outstanding class as of December 31, 2025.

What voting and dispositive powers does FMR LLC have over its Biogen (BIIB) shares?

FMR LLC reports sole voting power over 8,291,794.64 shares and sole dispositive power over 9,413,062.03 shares of Biogen common stock. It reports no shared voting or shared dispositive power over any Biogen shares in this Schedule 13G.

Does Abigail P. Johnson have voting power over Biogen (BIIB) shares in this filing?

Abigail P. Johnson reports no sole or shared voting power over Biogen shares in this filing. She reports sole dispositive power over 9,413,062.03 shares, representing 6.4% of Biogen’s common stock as of December 31, 2025.

Is the FMR LLC and Abigail P. Johnson Biogen (BIIB) stake intended to influence control?

The certification states the Biogen securities were acquired and are held in the ordinary course of business. It also specifies they were not acquired and are not held for the purpose of changing or influencing control of Biogen or in connection with such a transaction.

Do other investors share in dividends or sale proceeds from FMR’s Biogen (BIIB) holdings?

Yes. The filing notes that one or more other persons have rights to receive dividends or sale proceeds from the Biogen shares. However, no single such person’s interest relates to more than five percent of Biogen’s total outstanding common stock.