SCHEDULE: Citadel Amends Cabaletta Bio Stake to 3.4%

Citadel entities and Kenneth Griffin have filed an amended Schedule 13G, disclosing a combined beneficial ownership of 3.4% in Cabaletta Bio, Inc. as of September 30, 2025.

Summary

• Citadel Advisors LLC, Citadel Advisors Holdings LP, and Citadel GP LLC collectively beneficially own 2,905,465 shares, representing 3.1% of Cabaletta Bio, Inc.'s common stock.
• Citadel Securities LLC, Citadel Securities Group LP, and Citadel Securities GP LLC collectively beneficially own 244,810 shares, representing 0.3% of the common stock.
• Kenneth Griffin, through his control over the various Citadel entities, is deemed to beneficially own an aggregate of 3,150,275 shares, which constitutes 3.4% of the common stock.
• The percentages are based on 93,665,233 shares outstanding, including 91,465,233 shares as of August 1, 2025, and 2,200,000 shares issuable upon conversion of certain warrants held by affiliates of the reporting persons.
• The reporting persons disclaim that the securities were acquired or are held for the purpose of changing or influencing control of the issuer.

Sentiment

Score: 5

Explanation: The filing is a neutral, factual disclosure of beneficial ownership and does not contain information that would inherently sway sentiment positively or negatively.

Future Outlook

NA

Industry Context

This filing is a routine disclosure of passive institutional ownership in a biotechnology company. It does not provide specific insights into broader industry trends or competitive landscape, but the presence of a major investment firm like Citadel in a biotech company's stock can be noted by the market.

Stakeholder Impact

• Shareholders: Provides transparency regarding significant institutional ownership, which can influence investor perception and confidence.

Key Dates

Keywords

Cabaletta Bio, Citadel, Kenneth Griffin, Beneficial Ownership, Schedule 13G, Institutional Ownership, Biotechnology, Common Stock