SCHEDULE: Commodore Capital Discloses 5.1% Stake in Amylyx

Commodore Capital LP and its affiliates have reported a 5.1% beneficial ownership stake in Amylyx Pharmaceuticals, Inc., holding 5,650,000 shares of common stock.

Summary

• Commodore Capital LP, Commodore Capital Master LP, Robert Egen Atkinson, and Michael Kramarz collectively reported beneficial ownership of 5,650,000 shares of Amylyx Pharmaceuticals, Inc. Common Stock.
• This ownership represents 5.1% of the outstanding Common Stock of Amylyx Pharmaceuticals, Inc.
• The reporting persons hold shared voting power and shared dispositive power over all 5,650,000 shares.
• The ownership percentage is based on 109,819,569 Common Shares reported as issued and outstanding by Amylyx Pharmaceuticals, Inc. as of October 27, 2025, in its Quarterly Report on Form 10-Q filed on November 6, 2025.
• Commodore Capital LP acts as the investment manager to Commodore Capital Master LP, with Michael Kramarz and Robert Egen Atkinson serving as managing partners and exercising investment discretion.

Sentiment

Score: 5

Explanation: The filing is a factual disclosure of beneficial ownership and does not contain information that would inherently lead to a positive or negative sentiment regarding the issuer's performance or outlook. The presence of an institutional investor can be viewed neutrally or slightly positively depending on market interpretation.

Positives

• The disclosure of a significant 5.1% stake by an institutional investor like Commodore Capital may signal confidence in Amylyx Pharmaceuticals, Inc. from a notable investment firm.

Future Outlook

This filing is a disclosure of beneficial ownership and does not contain forward-looking statements or guidance from the issuer or the reporting persons regarding future performance or strategy.

Industry Context

This filing represents a standard disclosure of a significant passive investment by an institutional fund in a publicly traded biotechnology company. Such disclosures are common and provide transparency into institutional holdings, which can sometimes influence market perception of a company's value or prospects.

Stakeholder Impact

• Shareholders: The disclosure of a new institutional investor holding a significant stake may be viewed as a positive signal of institutional interest and confidence in Amylyx Pharmaceuticals, Inc.

Key Dates

Keywords

Amylyx Pharmaceuticals, Commodore Capital, Beneficial Ownership, Schedule 13G, Institutional Investment, Common Stock, Biotechnology