[Form 4] Amylyx Pharmaceuticals, Inc. Insider Trading Activity

Rhea-AI Filing Summary

James M. Frates, Chief Financial Officer of Amylyx Pharmaceuticals, Inc. (AMLX), reported a sale on 09/30/2025 of 10,558 shares of common stock at a weighted average price of $14.6477. The filing states the sales were automatic to cover tax withholding related to the vesting of restricted stock units and were not at the reporting person’s discretion. After the reported transactions, Mr. Frates beneficially owned 280,430 shares directly and held an additional 15,459 and 11,072 shares indirectly through two trusts for which he is trustee. The form is signed by an attorney-in-fact on 10/02/2025.

Positive

• 280,430 shares remain directly beneficially owned by the CFO after the transaction
• 15,459 and 11,072 shares are held indirectly in trusts where the reporting person is trustee

Negative

• 10,558 shares were sold on 09/30/2025, reducing the reporting person’s direct holdings
• Sale executed at a weighted average price of $14.6477, with individual trades ranging $14.35 to $15.075

Insights

Corporate Governance Specialist

Automatic RSU tax-sale; executive retains sizeable stake

The report shows a 09/30/2025 sale of 10,558 shares at a weighted average price of $14.6477 coded as a tax-withholding sale tied to vested restricted stock units. The filing explicitly states these sales were automatic and not at the reporting person’s discretion, which clarifies that the transaction was administrative rather than a voluntary divestiture.

Following the sale, the reporting person still holds 280,430 shares directly plus 15,459 and 11,072 shares indirectly in two trusts where he serves as trustee. That level of retained ownership indicates continued alignment with shareholders while complying with tax obligations.

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

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

FRATES JAMES M

(Last) (First) (Middle)

C/O AMYLYX PHARMACEUTICALS, INC.

43 THORNDIKE STREET

(Street)

CAMBRIDGE MA 02141

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Amylyx Pharmaceuticals, Inc. [ AMLX ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Financial Officer

3. Date of Earliest Transaction (Month/Day/Year)
09/30/2025

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	09/30/2025		S(1)		10,558(1)	D	$14.6477(2)	280,430	D
Common Stock								15,459	I	By Trust(3)
Common Stock								11,072	I	By Trust(4)

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

Explanation of Responses:

1. Represents shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units. Such sales were automatic and not at the discretion of the Reporting Person.

2. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $14.35 to $15.075. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

3. Shares held by the James M. Frates 2024 Grantor Retained Annuity Trust No. 1, for which the Reporting Person serves as trustee and is the sole annuitant. The Reporting Person disclaims beneficial ownership of such shares for purposes of Section 16 except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that such shares are beneficially owned by him for Section 16 or any other purpose.

4. Shares held by the FRATES FAMILY 2013 IRREV TRUST, for which the Reporting Person serves as trustee. The Reporting Person disclaims beneficial ownership of such shares for purposes of Section 16 except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that such shares are beneficially owned by him for Section 16 or any other purpose.

	/s/ Joshua B. Cohen, as Attorney in Fact	10/02/2025
	** 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.

FAQ

What transaction did AMLX insider James M. Frates report on Form 4?

The Form 4 reports a sale of 10,558 shares of AMLX common stock on 09/30/2025.

Why were the shares sold by AMLX CFO James M. Frates?

The filing states the shares were sold automatically to cover tax withholding obligations from the vesting of restricted stock units and were not at the reporting person’s discretion.

How many AMLX shares does James M. Frates beneficially own after the reported transaction?

He directly beneficially owns 280,430 shares and indirectly holds 15,459 and 11,072 shares through two trusts.

What price did the AMLX shares sell for in the reported transaction?

The weighted average price reported is $14.6477; individual sale prices ranged from $14.35 to $15.075.

When was the Form 4 signed and filed for the AMLX transaction?

The form bears a signature by an attorney-in-fact dated 10/02/2025.