Vanguard Group (AMLX) reveals 5.28% passive ownership stake in Amylyx

Rhea-AI Filing Summary

The Vanguard Group has filed a Schedule 13G reporting beneficial ownership of Amylyx Pharmaceuticals common stock. Vanguard reports beneficial ownership of 5,804,912 shares, representing 5.28% of the class as of the event date of 12/31/2025.

Vanguard has shared voting power over 698,623 shares and shared dispositive power over 5,804,912 shares, with no sole voting or dispositive power. The filing states the securities are held in the ordinary course of business, not to change or influence control, and that Vanguard’s clients have rights to dividends and sale proceeds, with no single client holding more than 5%.

Insights

Institutional ownership analyst

Vanguard discloses a 5.28% passive stake in Amylyx.

The Vanguard Group reports beneficial ownership of 5,804,912 Amylyx shares, or 5.28% of the common stock, under a Schedule 13G. This form and the certification language indicate a passive investment held in the ordinary course of business.

The filing shows no sole voting or dispositive power, but shared voting power over 698,623 shares and shared dispositive power over 5,804,912 shares. Vanguard notes an internal realignment on January 12, 2026, after which certain subsidiaries may report ownership separately.

The statement clarifies that Vanguard’s clients receive dividends and sale proceeds and that no other single person’s interest exceeds 5% of the class. Future ownership disclosures may appear from specific Vanguard-affiliated entities following the realignment, but this document itself presents a consolidated, passive 5.28% position.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Amylyx Pharmaceuticals Inc

(Name of Issuer)

Common Stock

(Title of Class of Securities)

03237H101

(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. 03237H101

1

Names of Reporting Persons

The Vanguard Group

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 0.00
6	Shared Voting Power 698,623.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 5,804,912.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

5,804,912.00

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)

5.28 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: On January 12, 2026, The Vanguard Group, Inc. went through an internal realignment. As of that date, The Vanguard Group, Inc. no longer performs portfolio management services or administers proxy voting. In accordance with SEC Release No. 34-39538 (January 12, 1998), The Vanguard Group, Inc. anticipates that certain subsidiaries or business divisions of subsidiaries of The Vanguard Group, Inc., that currently have, or are deemed to have, beneficial ownership with The Vanguard Group, Inc., will report beneficial ownership separately (on a disaggregated basis) from The Vanguard Group, Inc. in reliance on such release. These subsidiaries and/or business divisions pursue the same investment strategies as previously pursued by The Vanguard Group, Inc. prior to the realignment.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Amylyx Pharmaceuticals Inc
(b)	Address of issuer's principal executive offices: 43 Thorndike Street, Cambridge, MA, 02141
Item 2.
(a)	Name of person filing: The Vanguard Group
(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 No.: 03237H101
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: 5804912
(b)	Percent of class: 5.28 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 698623
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 5804912
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. The Vanguard Group, Inc.'s clients, 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.

The Vanguard Group

Signature:	Ashley Grim
Name/Title:	Head of Global Fund Administration
Date:	01/30/2026

FAQ

What percentage of Amylyx Pharmaceuticals (AMLX) does The Vanguard Group own?

The Vanguard Group reports beneficial ownership of 5.28% of Amylyx Pharmaceuticals common stock. This represents 5,804,912 shares as of the reported event date, making Vanguard a significant institutional holder while filing on a passive Schedule 13G basis.

How many Amylyx (AMLX) shares does Vanguard report as beneficially owned?

The Vanguard Group reports beneficial ownership of 5,804,912 Amylyx Pharmaceuticals common shares. This stake equals 5.28% of the outstanding common stock, based on the issuer’s share count referenced in the Schedule 13G filing for the 12/31/2025 event date.

Does Vanguard have voting power over its Amylyx Pharmaceuticals (AMLX) stake?

Vanguard reports no sole voting power, but shared voting power over 698,623 Amylyx shares. It also reports shared dispositive power over 5,804,912 shares, indicating voting and selling decisions are made collectively, consistent with its role managing assets for multiple clients.

Is Vanguard’s Amylyx (AMLX) investment classified as passive or active?

The investment is classified as passive under Schedule 13G. Vanguard certifies the Amylyx securities were acquired and are held in the ordinary course of business, not for the purpose of changing or influencing control of the issuer, consistent with a passive institutional position.

Who ultimately benefits from Vanguard’s Amylyx Pharmaceuticals (AMLX) holdings?

Vanguard states its clients benefit from the Amylyx holdings. These include registered investment companies and other managed accounts, which receive dividends and sale proceeds, and no single other person’s interest in the reported securities exceeds 5% of the Amylyx common stock class.

What internal changes at Vanguard are mentioned in the Amylyx (AMLX) 13G filing?

The filing notes an internal realignment effective January 12, 2026. After this date, The Vanguard Group, Inc. no longer provides portfolio management or proxy voting, and certain subsidiaries or business divisions may report beneficial ownership separately on a disaggregated basis under SEC guidance.