Amylyx insider plans 60K-share tax sale in 2026

Rule 144 notice covers 60,039 AMLX shares to be sold automatically to cover tax withholding from performance-based RSU vesting.

Rhea-AI Filing Summary

Amylyx Pharmaceuticals, Inc. (AMLX) received a notice under Rule 144 relating to a planned sale of common stock for the account of Justin B. Klee. The notice covers 60,039 shares of common stock expected to be sold on September 10, 2026, in connection with vesting of performance-based restricted stock units.

The filing states that these shares are required to be sold to satisfy tax withholding obligations upon vesting and that the sales are automatic and not at the discretion of the reporting person. Morgan Stanley Smith Barney LLC is listed as the broker for the transaction, and the shares are listed on NASDAQ.

Key Figures

Shares covered by Rule 144 notice: 60,039 shares Expected sale date: September 10, 2026 Form 144 notice date: September 11, 2026

3 metrics

Shares covered by Rule 144 notice 60,039 shares Common stock to be sold in connection with vesting of performance-based restricted stock units

Expected sale date September 10, 2026 Planned sale date for the 60,039 shares of common stock

Form 144 notice date September 11, 2026 Date the notice of proposed sale under Rule 144 was signed and dated

Key Terms

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

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.

tax withholding obligations financial

"shares required to be sold by the Reporting Person to cover tax withholding obligations"

automatic other

"Such sales were automatic and not at the discretion of the Reporting Person"

FAQ

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

What does the Form 144 filing disclose for Amylyx Pharmaceuticals (AMLX)?

It discloses a Rule 144 notice for the potential sale of 60,039 shares of Amylyx common stock for the account of Justin B. Klee, related to the vesting of performance-based restricted stock units and intended to cover tax withholding obligations.

How many AMLX shares are covered by this Rule 144 notice?

The notice covers 60,039 shares of Amylyx Pharmaceuticals common stock. These shares are tied to the vesting of performance-based restricted stock units and are to be sold to satisfy tax withholding obligations, according to the disclosure.

When are the AMLX shares referenced in the Form 144 expected to be sold?

The Form 144 indicates an expected sale date of September 10, 2026 for the 60,039 shares of Amylyx common stock that are associated with the vesting of performance-based restricted stock units.

Why is Justin B. Klee’s AMLX stock being sold under this Form 144?

The shares are reported as being sold to cover tax withholding obligations arising from the vesting of performance-based restricted stock units. The filing states the sales were automatic and not at the discretion of the reporting person.

Which broker is handling the planned AMLX share sale under Rule 144?

The notice lists Morgan Stanley Smith Barney LLC as the broker for the planned sale of Amylyx Pharmaceuticals common stock, with the shares listed for trading on NASDAQ.

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	0001898314
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	Klee Justin B.
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
Relationship to Issuer	Director

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	30464	980264	3613056	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			60039	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)