SCHEDULE: Pentwater Capital Exits 89bio Stake, Reports 0% Ownership

Pentwater Capital Management LP and Matthew Halbower have reported a complete divestment of their 7.9% stake in 89bio, Inc. as of the filing date.

Summary

• Pentwater Capital Management LP and Matthew Halbower, collectively referred to as the Reporting Persons, filed a Schedule 13G regarding their ownership in 89bio, Inc.
• As of September 30, 2025, the Reporting Persons beneficially owned 11,750,000 shares of 89bio, Inc. Common Stock, representing 7.9% of the outstanding shares.
• The percentage was calculated based on 148,492,428 shares of Common Stock outstanding as of September 16, 2025.
• As of the filing date, November 14, 2025, the Reporting Persons reported 0 shares beneficially owned, representing 0% of the class.
• The filing certifies that the securities were acquired and held in the ordinary course of business and not for the purpose of changing or influencing control of 89bio, Inc.

Sentiment

Score: 3

Explanation: The sentiment is negative due to the complete divestment of a significant 7.9% stake by a major institutional investor, Pentwater Capital Management, which typically signals a lack of confidence or a strategic exit.

Negatives

• A significant institutional investor, Pentwater Capital Management LP, has fully divested its 7.9% stake in 89bio, Inc., which could signal a loss of confidence or a strategic shift by a major holder.

Risks

• The divestment by a major institutional investor could lead to negative market sentiment and potential downward pressure on 89bio, Inc.'s stock price.

Future Outlook

No forward-looking statements or guidance for 89bio, Inc. were provided in this filing.

Industry Context

In the biotechnology sector, significant institutional investor movements, especially divestments, are closely watched as they can reflect investor sentiment regarding a company's prospects, pipeline, or market position. The exit of a major holder like Pentwater Capital Management could be interpreted by the market as a negative signal for 89bio, Inc.

Stakeholder Impact

• Shareholders of 89bio, Inc. may experience negative sentiment and potential downward pressure on the stock price due to the divestment by a major institutional investor.

Key Dates

Recommendation

A significant institutional investor, Pentwater Capital Management, has fully divested its 7.9% stake in 89bio, Inc. This suggests a loss of confidence or a strategic shift by a major holder, which could put substantial downward pressure on the stock price and signals a negative outlook from a sophisticated investor. Investors should consider this strong negative signal.

Keywords

89bio Inc, Pentwater Capital Management, Matthew Halbower, Schedule 13G, Institutional Ownership, Common Stock, Biotech, Divestment