Vanguard Capital Management (NASDAQ: BIIB) reports 10.99M Biogen shares ownership

Rhea-AI Filing Summary

Biogen Inc ownership filing: Vanguard Capital Management reports beneficial ownership of 10,989,562 shares of Biogen common stock, representing 7.48% of the class. The filing shows Vanguard has sole voting power for 1,452,145 shares and sole dispositive power for 10,989,562 shares.

The Schedule 13G statement describes holdings across Vanguard business units and notes the reported interests include shares held for Vanguard funds and other managed accounts.

Insights

Institutional Ownership Analyst

Vanguard owns 7.48% of Biogen, a visible institutional stake.

The filing shows 10,989,562 shares beneficially owned and a 7.48% stake, reported on a Schedule 13G indicating passive, long‑term ownership. The report aggregates holdings across Vanguard Capital Management and affiliated advisory units.

Key dependencies include fund flows and client mandates that determine whether Vanguard's position remains passive; future amendments would appear if voting or disposition powers change.

Corporate Governance Expert

Disclosure clarifies voting and dispositive authority within Vanguard's business units.

The statement specifies sole voting power for 1,452,145 shares and sole dispositive power for 10,989,562 shares, with no shared powers reported. It follows SEC Release No. 34-39538 aggregation guidance for affiliated advisory divisions.

Any shift from passive to active status or changes in voting power would require an updated filing; timing of such changes is not provided in the excerpt.

Key Figures

Beneficially owned shares: 10,989,562 shares Percent of class: 7.48% Sole voting power: 1,452,145 shares +3 more

6 metrics

Beneficially owned shares 10,989,562 shares Item 4(a) reported on Schedule 13G

Percent of class 7.48% Item 4(b) percentage ownership

Sole voting power 1,452,145 shares Item 4(c)(i) voting power

Sole dispositive power 10,989,562 shares Item 4(c)(iii) disposition authority

Filing type Schedule 13G Cover and Item headings

Signature date 04/29/2026 Signature block

Key Terms

Schedule 13G, beneficially owned, sole dispositive power, aggregation guidance (SEC Release No. 34-39538)

4 terms

Schedule 13G regulatory

"Item headings and cover referencing passive ownership filing"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

beneficially owned financial

"Item 4(a) Amount beneficially owned: 10989562"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

sole dispositive power regulatory

"Item 4(c)(iii) Sole power to dispose: 10989562"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

aggregation guidance (SEC Release No. 34-39538) regulatory

"Comment explaining aggregation of affiliates and business divisions"

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)

03/31/2026

(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)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 09062X103

1

Names of Reporting Persons

Vanguard Capital Management

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

PENNSYLVANIA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 1,452,145.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 10,989,562.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

10,989,562.00

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)

7.48 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: In accordance with SEC Release No. 34-39538 (January 12, 1998), this Schedule 13G reflects the securities beneficially owned, or deemed to be beneficially owned, by Vanguard Capital Management LLC and the following affiliates of Vanguard Capital Management LLC or business divisions of such affiliates: Vanguard Asset Management Limited, Vanguard Fiduciary Trust Company, Vanguard Global Advisers, LLC and Vanguard Investments Australia Ltd. This Schedule 13G includes securities held by Vanguard funds, or sleeves thereof, over which Vanguard Capital Management LLC exercises dispositive power, in addition to securities held by clients over which the affiliates or business divisions of such affiliates indicated above exercise dispositive and/or voting power. This Schedule 13G does not include securities, if any, beneficially owned by other subsidiaries or affiliates of Vanguard Capital Management LLC, or business divisions of such subsidiaries, whose ownership of securities is disaggregated from that of the reporting business unit in accordance with such release.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Biogen Inc
(b)	Address of issuer's principal executive offices: 225 Binney Street, Cambridge, MA, 02142
Item 2.
(a)	Name of person filing: Vanguard Capital Management
(b)	Address or principal business office or, if none, residence: 100 Vanguard Blvd,, Malvern, PA, 19355
(c)	Citizenship: PA
(d)	Title of class of securities: Common Stock
(e)	CUSIP Number(s): 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: 10989562
(b)	Percent of class: 7.48 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 1452145
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 10989562
	(iv) Shared power to dispose or to direct the disposition of: 0
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. Vanguard Capital Management, including investment companies registered under the Investment Company Act of 1940 and other managed accounts, have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the securities reported herein.No one other person's interest in the securities reported herein is more than 5%.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
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.

Vanguard Capital Management

Signature:	Ashley Grim
Name/Title:	Head of Global Fund Administration
Date:	04/29/2026

FAQ

How many Biogen (BIIB) shares does Vanguard report owning?

Vanguard reports beneficial ownership of 10,989,562 shares of Biogen common stock, representing 7.48% of the class. The figure is stated in Item 4(a) of the Schedule 13G.

Does Vanguard have voting control over the Biogen shares?

Vanguard reports sole voting power for 1,452,145 shares and shared voting power of 0. Voting powers are listed in Item 4(c)(i) and (ii) of the filing.

What does 'sole dispositive power' mean in this filing?

The filing shows Vanguard has sole dispositive power over 10,989,562 shares, meaning Vanguard can direct the sale or disposition of those shares. That amount is shown in Item 4(c)(iii).

Is this Schedule 13G an active or passive disclosure?

The document is a Schedule 13G, which is used for passive beneficial owners. The filing text and aggregation across Vanguard units indicate reporting as an institutional, passive holder.

When was the Schedule 13G signed and filed?

The signature block shows the filing was signed by Ashley Grim, Head of Global Fund Administration, with a signature date of 04/29/2026. The cover lists an issuer date of 03/31/2026.