Amylyx Pharmaceuticals SEC Filings

Amylyx Pharmaceuticals (AMLX) reported that it issued a press release announcing financial results for the fiscal quarter ended September 30, 2025. The press release is furnished as Exhibit 99.1 to this report.

The information in this item, including Exhibit 99.1, is being furnished and is not deemed filed for purposes of Section 18 of the Exchange Act, and is not incorporated by reference into other filings except as expressly set forth by specific reference.

Amylyx Pharmaceuticals has a passive ownership filing showing that FMR LLC and Abigail P. Johnson together report beneficial ownership of 11,379,207 shares of common stock, representing 10.7% of the outstanding class. The filing shows FMR LLC holds 11,361,910 shares with sole voting power for that portion and sole dispositive power over 11,379,207 shares, while Abigail P. Johnson is reported with sole dispositive power over the full 11,379,207 shares and no voting power. The statement clarifies the stake is held in the ordinary course of business and not to change control.

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.

Gina Mazzariello, Chief Legal Officer of Amylyx Pharmaceuticals, Inc. (AMLX), reported the automatic sale of 8,828 shares of common stock to satisfy tax withholding related to the vesting of restricted stock units. The weighted average price reported for the sales was $14.5751, with execution prices ranging from $14.355 to $15.075. After the transaction, the filing shows the reporting person beneficially owns 148,141 shares. The filing notes the sales were automatic to cover tax obligations and not at the reporting person's discretion.

James M. Frates, Chief Financial Officer of Amylyx Pharmaceuticals, Inc. (AMLX), reported a sale on 09/30/2025 of 10,558 shares of common stock at a weighted average price of $14.6477. The filing states the sales were automatic to cover tax withholding related to the vesting of restricted stock units and were not at the reporting person’s discretion. After the reported transactions, Mr. Frates beneficially owned 280,430 shares directly and held an additional 15,459 and 11,072 shares indirectly through two trusts for which he is trustee. The form is signed by an attorney-in-fact on 10/02/2025.

Joshua B. Cohen, Co‑Chief Executive Officer and Director of Amylyx Pharmaceuticals, Inc. (AMLX), reported two automatic sales of common stock tied to the vesting of restricted stock units on 09/30/2025. The Form 4 shows a sale of 29,733 shares at a weighted average price of $14.3433 and a sale of 200 shares at a weighted average price of $14.9975; the filings state those sales were automatic to satisfy tax withholding obligations. After the transactions the reporting person beneficially owned 3,325,347 shares according to the Form 4. The filing notes the trades occurred across multiple execution prices within the ranges disclosed and that detailed breakdowns can be provided to the SEC on request.

Camille L. Bedrosian, Chief Medical Officer of Amylyx Pharmaceuticals (AMLX), reported automatic sales of 12,039 shares on 09/30/2025 to satisfy tax withholding from restricted stock unit vesting. The disclosure shows a weighted average sale price of $14.5791 (individual sale prices ranged from $14.35 to $15.04). After the reported transactions, the reporting person beneficially owns 182,336 shares, held directly. The filing notes the sales were automatic to cover tax obligations and not at the reporting person's discretion.

Amylyx Pharmaceuticals filed a Current Report (Form 8-K) that includes an underwriting agreement dated September 9, 2025, and counsel materials from Goodwin Procter LLP. The filing discloses that an opinion and consent of Goodwin Procter LLP are included as exhibits, and that the cover page interactive data file is embedded within the Inline XBRL document. The report contains a standard forward-looking statements caution referencing prior SEC reports and urges investors not to rely solely on forward-looking statements. The filing is signed by James M. Frates, Chief Financial Officer, dated September 10, 2025.

Amylyx Pharmaceuticals (AMLX) is offering shares under a shelf registration with a base offering of 17,500,000 shares at $10.00 per share, representing gross proceeds of $175,000,000 ($201,250,000 if the underwriters' option is exercised). Net proceeds are intended to advance avexitide commercial readiness and for R&D, working capital and general corporate purposes. Avexitide is a GLP-1 receptor antagonist being developed for post-bariatric hypoglycemia (PBH) and congenital hyperinsulinism; FDA granted Breakthrough Therapy, Rare Pediatric Disease and Orphan Drug designations for relevant indications. In April 2025 Amylyx dosed the first participant in the Phase 3 LUCIDITY trial in PBH (≈75 participants randomized 3:2 to 90 mg once daily or placebo); topline data are anticipated in H1 2026 with potential commercial launch in 2027 if approved. The prospectus also discloses clinical programs for AMX0035 (Wolfram syndrome Phase 2 open-label data through Week 48) and AMX0114 (Phase 1 LUMINA dosing began in Canada April 2025; ≈48 participants randomized 3:1).