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

Rhea-AI Filing Summary

Justin B. Klee, Co-Chief Executive Officer and a director of Amylyx Pharmaceuticals, Inc. (AMLX), reported sales of company common stock that were automatic to cover tax withholding on vested restricted stock units. On 09/30/2025 the reporting shows 29,775 shares sold at a weighted average price of $14.3728 and an additional 200 shares sold at a weighted average price of $15.01. After these transactions the filing reports total beneficial ownership of 3,325,301 shares (direct). The filing notes the sales were mandatory to satisfy tax obligations and were executed in multiple trades at prices within the disclosed ranges.

Positive

• Timely disclosure of insider transactions showing compliance with reporting obligations
• Sales were automatic to cover tax withholding on vested restricted stock units, not discretionary trades

Negative

• Insider sold 29,975 shares in total, modestly reducing direct ownership
• Sales occurred at market prices between $13.99 and $15.02, realizing proceeds that reduce insider equity exposure

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
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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^*

Klee Justin B.

(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)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Co-Chief Executive 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)		29,775(1)	D	$14.3728(2)	3,325,501	D
Common Stock	09/30/2025		S(1)		200(1)	D	$15.01(3)	3,325,301	D

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 $13.99 to $14.98. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

3. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $15.00 to $15.02. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

	/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 transactions did AMLX insider Justin B. Klee report?

The report shows automatic sales of 29,775 shares at a weighted average of $14.3728 and 200 shares at $15.01 on 09/30/2025 to cover tax withholding on vested RSUs.

Why were the AMLX shares sold by the reporting person?

The filing states the sales were required to cover tax withholding obligations tied to the vesting of restricted stock units and were automatic, not discretionary.

How many AMLX shares does Justin B. Klee beneficially own after the transactions?

The filing reports 3,325,301 shares beneficially owned following the reported transactions.

Were the share sales executed at a single price?

No; the filing discloses the sales occurred in multiple transactions with prices ranging from $13.99 to $14.98 for the larger lot and $15.00 to $15.02 for the smaller lot.

Do the reported transactions indicate discretionary insider selling?

No; the filing explicitly states the sales were automatic and required to satisfy tax withholding on vested awards.