Amylyx officer plans Rule 144 tax-share sale

A Rule 144 filing reports automatic sales of AMLX common stock by James M. Frates to cover tax withholding on performance-based RSU vesting.

Rhea-AI Filing Summary

Amylyx Pharmaceuticals, Inc. (AMLX) received a Rule 144 notice indicating that James M. Frates intends to sell common stock through Morgan Stanley Smith Barney LLC. The sales are connected to the vesting of performance-based restricted stock units scheduled for September 10, 2026.

The filing states that the shares are being sold to satisfy tax withholding obligations arising from this vesting and that these sales were automatic and not at the discretion of the reporting person.

Key Terms

Rule 144, performance-based Restricted Stock Units, performance stock units, tax withholding obligations

4 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144"

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

performance-based Restricted Stock Units financial

"Vesting of Performance-based Restricted Stock Units"

Performance-based restricted stock units are a type of employee equity award that converts into company shares only if predefined financial or operational targets are met over a set period. Think of it like a bonus check that becomes stock only when specific goals are hit; it ties pay to results, aligning managers’ incentives with shareholders. Investors care because these awards affect future share count, executive incentives, and signal how management’s success will be measured and rewarded.

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

"to cover tax withholding obligations in connection with the vesting"

FAQ

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

What does the Form 144 filing for AMLX disclose?

It discloses that James M. Frates plans to sell Amylyx Pharmaceuticals, Inc. common stock under Rule 144. The sales relate to the vesting of performance-based restricted stock units on September 10, 2026 and are being made to cover tax withholding obligations.

Who is selling Amylyx (AMLX) shares in this Form 144 notice?

The notice identifies James M. Frates as the person for whose account the Amylyx Pharmaceuticals, Inc. common stock is to be sold. The filing also notes that he is an officer of the issuer.

Why are AMLX shares being sold according to this Form 144?

The filing states that the sale represents shares required to be sold to cover tax withholding obligations in connection with the vesting of performance stock units. It further notes that these sales were automatic and not at the discretion of the reporting person.

When are the AMLX-related transactions connected to this Form 144 scheduled?

The Rule 144 notice references activity on September 10, 2026, tied to the vesting of performance-based restricted stock units. The date of the notice itself is September 11, 2026.

Which broker is involved in the planned AMLX share sale?

The filing lists Morgan Stanley Smith Barney LLC, located at 1 New York Plaza, as the broker associated with the Amylyx Pharmaceuticals, Inc. common stock covered by this Rule 144 notice.

Are the AMLX share sales under this Form 144 discretionary?

No. The remarks specify that the sales were automatic and not at the discretion of the Reporting Person, and that they were required to satisfy tax withholding obligations from performance stock unit vesting.

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

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Available on EDGAR 09/11/2026 - 04:01 PM Accepted by SEC EDGAR 09/11/2026 - 04:01 PM Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001235598
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	Amylyx Pharmaceuticals, Inc.
SEC File Number	001-41199
Address of Issuer	55 Cambridge Parkway Suite 6W Cambridge MASSACHUSETTS 02142
Phone	617-682-0917
Name of Person for Whose Account the Securities are To Be Sold	Frates James M
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Morgan Stanley Smith Barney LLC 1 New York Plaza 8th Floor New York NY 10004	10810	349821	233625	09/10/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	09/10/2026	Vesting of Performance-based Restricted Stock Units	Issuer			22807	09/10/2026	N/A

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Nothing to Report

144: Remarks and Signature

Remarks	This sale 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.
Date of Notice	09/11/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Joshua B. Cohen, as Attorney in Fact
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)