Amylyx officer plans 21,284-share tax sale

Officer-related Rule 144 notice covers automatic, tax-withholding share sales tied to vested performance-based stock units at Amylyx Pharmaceuticals.

Rhea-AI Filing Summary

Amylyx Pharmaceuticals, Inc. (AMLX) has a notice filed on behalf of officer Gina Mazzariello for the potential sale of 21,284 shares of common stock under Rule 144 in connection with the vesting of performance-based restricted stock units on September 10, 2026. The shares represent amounts required to be sold to cover tax withholding obligations, and the filing states the sales were automatic and not at her discretion. In the prior three months, she reported sales totaling 30,000 shares of common stock for the same person.

Key Figures

Shares to be potentially sold: 21,284 shares Shares sold July 9, 2026: 15,000 shares Amount for July 9, 2026 sale: 274,746 +3 more

6 metrics

Shares to be potentially sold 21,284 shares Common stock tied to vesting of performance-based restricted stock units on September 10, 2026

Shares sold July 9, 2026 15,000 shares Common stock sold by Gina Mazzariello in past three months section

Amount for July 9, 2026 sale 274,746 Total for 15,000 shares of common stock sold July 9, 2026

Shares sold July 10, 2026 15,000 shares Common stock sold by Gina Mazzariello in past three months section

Amount for July 10, 2026 sale 264,122 Total for 15,000 shares of common stock sold July 10, 2026

Date of Notice September 11, 2026 Date the Rule 144 notice was signed

Key Terms

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

3 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 ... to cover tax withholding obligations in connection"

FAQ

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

What does AMLX’s latest Rule 144 notice disclose about Gina Mazzariello’s shares?

It discloses a potential sale of 21,284 shares of Amylyx common stock under Rule 144 tied to the vesting of performance-based restricted stock units on September 10, 2026, with the filing stating the shares are to cover tax withholding obligations.

How many AMLX shares are covered by the new Rule 144 notice?

The notice covers a potential sale of 21,284 shares of Amylyx Pharmaceuticals common stock associated with the vesting of performance-based restricted stock units on September 10, 2026.

Were Gina Mazzariello’s AMLX share sales discretionary?

The filing states the sale represents shares required to be sold to cover tax withholding obligations in connection with the vesting of performance stock units and that such sales were automatic and not at the discretion of Gina Mazzariello.

What AMLX share sales has Gina Mazzariello reported in the past three months?

She reported selling 15,000 shares of Amylyx common stock on July 9, 2026 and another 15,000 shares on July 10, 2026, for total amounts of 274,746 and 264,122, respectively.

Which broker is listed for Gina Mazzariello’s AMLX Rule 144 transaction?

The broker listed for the Amylyx Pharmaceuticals common stock covered by the Rule 144 notice is Morgan Stanley Smith Barney LLC, 1 New York Plaza, 8th Floor, New York, NY 10004.

When was the Rule 144 notice for AMLX filed for Gina Mazzariello?

The Rule 144 notice for Amylyx Pharmaceuticals common stock related to Gina Mazzariello was dated September 11, 2026.

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	0001913765
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	Mazzariello Gina
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	9536	309506	190838	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			21284	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

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
Mazzariello Gina 55 Cambridge Parkway Suite 6W Cambridge MA 02142	Common	07/09/2026	15000	274746
Mazzariello Gina 55 Cambridge Parkway Suite 6W Cambridge MA 02142	Common	07/10/2026	15000	264122

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)