Amylyx co-CEO sells 30K shares for tax withholding

Amylyx’s co-CEO reported automatic share sales to satisfy tax withholding tied to vesting performance stock units.

Rhea-AI Filing Summary

Amylyx Pharmaceuticals, Inc. (AMLX) reported that Co-Chief Executive Officer and director Joshua B. Cohen sold a total of 30,464 shares of common stock on September 10, 2026. The filing states these automatic sales were made solely to cover tax withholding obligations from vesting performance stock units and were not at his discretion, with no Rule 10b5-1 plan reported.

Insider Trade Summary

Net Seller: 30,464 shares

Net Sell 2 txns

Insider Cohen Joshua B

Role Co-Chief Executive Officer

Sold 30,464 shs ($981K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1, F2	29,545	$32.1557	$950K
Sale	Common Stock F1, F3	919	$33.1488	$30K

Holdings After Transaction: Common Stock — 3,613,123 shares (Direct)

Footnotes (3)

1. F1. Represents shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of performance stock units. Such sales were automatic and not at the discretion of the Reporting Person.
2. F2. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $31.81 to $32.73. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.
3. F3. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $32.855 to $33.27. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

Key Figures

Total shares sold: 30,464 shares First sale size: 29,545 shares First sale weighted average price: $32.1557 per share +2 more

5 metrics

Total shares sold 30,464 shares Common stock sold by Joshua B. Cohen on September 10, 2026

First sale size 29,545 shares Common stock sale at weighted average price reported on September 10, 2026

First sale weighted average price $32.1557 per share Shares sold in multiple transactions between $31.81 and $32.73

Second sale size 919 shares Common stock sale at weighted average price reported on September 10, 2026

Second sale weighted average price $33.1488 per share Shares sold in multiple transactions between $32.855 and $33.27

Key Terms

performance stock units, tax withholding obligations, weighted average price

3 terms

performance stock units financial

"in connection with the vesting of performance stock units"

Performance stock units are a type of company award that grants employees shares of stock only if certain performance goals are met. They motivate employees to work toward specific company achievements, aligning their interests with those of shareholders. For investors, they can influence a company's future stock supply and reflect management’s confidence in reaching key targets.

tax withholding obligations financial

"shares required to be sold ... to cover tax withholding obligations"

weighted average price financial

"The price reported in Column 4 is a weighted average price"

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did AMLX report in this Form 4?

Amylyx Pharmaceuticals reported that Co-Chief Executive Officer Joshua B. Cohen sold 30,464 shares of common stock on September 10, 2026. The transactions were reported as sales in the open market or private transactions.

Why did the Amylyx (AMLX) co-CEO sell shares according to this filing?

The filing states the shares were sold to cover tax withholding obligations in connection with the vesting of performance stock units. It notes these sales were automatic and not at the discretion of Joshua B. Cohen.

How many AMLX shares did Joshua B. Cohen sell and at what prices?

Joshua B. Cohen sold 29,545 shares at a weighted average price of $32.1557 and 919 shares at a weighted average price of $33.1488, for a total of 30,464 shares on September 10, 2026.

Were the AMLX insider sales under a Rule 10b5-1 trading plan?

No. The Form 4 indicates no Rule 10b5-1 plan for these transactions. Instead, a footnote explains the sales were automatic to satisfy tax withholding on vesting performance stock units.

Over what price ranges were the AMLX shares sold in these transactions?

For the 29,545-share sale, the filing reports a weighted average price with individual trades between $31.81 and $32.73. For the 919-share sale, trades occurred between $32.855 and $33.27, both reported as weighted average prices.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/14/2026 - 04:00 PM Accepted by SEC EDGAR 09/14/2026 - 04:00 PM Learn about SEC filing dates

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
Estimated average burden
hours per response:			0.5

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

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Cohen Joshua B

(Last) (First) (Middle)

C/O AMYLYX PHARMACEUTICALS, INC.

55 CAMBRIDGE PARKWAY, SUITE 6W

(Street)

CAMBRIDGE MASSACHUSETTS 02142

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/10/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	09/10/2026		S(1)		29,545	D	$32.1557(2)	3,614,042	D
Common Stock	09/10/2026		S(1)		919	D	$33.1488(3)	3,613,123	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 performance 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 $31.81 to $32.73. 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 $32.855 to $33.27. 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	09/14/2026
	** 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.
* Form 4: SEC 1474 (03-26)