SCHEDULE: Alyeska Investment Group Discloses 6.03% Stake in Cabaletta Bio

Alyeska Investment Group, L.P. and its affiliates reported a 6.03% beneficial ownership stake in Cabaletta Bio, Inc., comprising common stock and warrants.

Summary

• Alyeska Investment Group, L.P., Alyeska Fund GP, LLC, and Anand Parekh collectively reported beneficial ownership of 5,800,000 shares of Cabaletta Bio, Inc. Common Stock.
• This aggregate amount represents 6.03% of Cabaletta Bio, Inc.'s outstanding Common Stock.
• The ownership consists of 1,300,000 shares of Common Stock and warrants to purchase an additional 4,500,000 shares of Common Stock.
• The percentage calculation is based on 96,265,204 outstanding Common Stock of Cabaletta Bio, Inc., as reported in the Issuer's Form 10-Q filed on November 10, 2025.
• The reporting persons have shared voting power and shared dispositive power over all 5,800,000 beneficially owned shares.
• The securities were acquired and are held in the ordinary course of business, not for the purpose of changing or influencing control of the issuer.

Sentiment

Score: 7

Explanation: The filing indicates a significant passive investment by Alyeska Investment Group, suggesting institutional confidence in Cabaletta Bio, Inc. without implying control or specific operational changes. This is generally viewed as a positive signal of market interest.

Positives

• A significant institutional investor, Alyeska Investment Group, has disclosed a substantial passive stake (6.03%) in Cabaletta Bio, which may signal confidence in the company's long-term prospects.
• The investment includes both direct common stock and warrants, indicating a strategic position.

Future Outlook

This filing is a disclosure of beneficial ownership and does not contain forward-looking statements or guidance from the reporting persons regarding Cabaletta Bio, Inc.'s future performance or strategic direction.

Management Comments

• "To the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities."

Industry Context

Cabaletta Bio, Inc. operates in the biotechnology sector. The disclosure of a significant passive stake by an investment group like Alyeska is a common occurrence in the public markets, reflecting institutional investment activity in companies within growth-oriented sectors such as biotech.

Stakeholder Impact

• Shareholders: Increased institutional ownership may be viewed positively, potentially signaling confidence in the company's prospects and potentially attracting further investor interest.

Key Dates

Recommendation

The disclosure of a significant passive stake by Alyeska Investment Group indicates institutional interest and potential confidence in Cabaletta Bio, Inc. While not a direct endorsement of future performance, such a substantial holding by a reputable investment group can be a positive signal for existing shareholders, warranting a 'hold' recommendation based solely on this ownership filing. It does not provide enough information to suggest a 'buy' or 'sell' at this time.

Keywords

Cabaletta Bio, Alyeska Investment Group, Schedule 13G, Beneficial Ownership, Biotechnology, Investment, Warrants, Common Stock