SCHEDULE 13D/A: RA Capital Management Affirms 13.7% Stake in 89bio, Inc. Following Updated Share Count

RA Capital Management and its affiliates have reaffirmed their aggregate 13.7% beneficial ownership in 89bio, Inc., reflecting an updated total outstanding share count for the biopharmaceutical company.

Summary

• RA Capital Management, L.P., Peter Kolchinsky, Rajeev Shah, and RA Capital Healthcare Fund, L.P. (the "Reporting Persons") have filed Amendment No. 13 to their Schedule 13D regarding their beneficial ownership of 89bio, Inc. Common Stock.
• The Reporting Persons collectively beneficially own an aggregate of 20,013,733 shares of 89bio, Inc. Common Stock.
• This aggregate ownership represents 13.7% of 89bio, Inc.'s outstanding Common Stock.
• The percentage is calculated based on 145,984,182 shares of Common Stock outstanding as of February 24, 2025, as reported in 89bio, Inc.'s Annual Report on Form 10-K, plus 124,050 shares issuable from stock options.
• RA Capital Healthcare Fund, L.P. directly holds 19,554,319 shares, representing 13.4% of the class.
• RA Capital Nexus Fund, L.P. holds 335,364 shares.
• The Reporting Persons have not conducted any transactions with 89bio, Inc. securities since their last amendment. The reported percentage ownership reflects an increase in the Issuer's total outstanding shares.
• The Fund also holds 4,331,081 pre-funded warrants (PFWs) which are currently not exercisable due to a "PFW Beneficial Ownership Blocker" that prevents ownership from exceeding 9.99% of the Issuer's outstanding Common Stock upon exercise.

Sentiment

Score: 5

Explanation: The document is a routine regulatory filing updating beneficial ownership. It contains no new operational or financial information that would significantly alter sentiment. The continued stable ownership by a major healthcare investor is neutral to slightly positive, but the lack of new information keeps it at a neutral score.

Positives

• Continued significant stake by a specialized healthcare investment firm (RA Capital Management) indicates ongoing confidence in 89bio, Inc.
• The stability of the percentage ownership (13.7%) despite an increase in the Issuer's outstanding shares suggests a consistent long-term investment strategy by RA Capital.

Negatives

• The "PFW Beneficial Ownership Blocker" prevents the exercise of 4,331,081 pre-funded warrants, limiting RA Capital's ability to increase its direct equity stake beyond the 9.99% threshold through these instruments.

Risks

• The "PFW Beneficial Ownership Blocker" on 4,331,081 pre-funded warrants limits RA Capital's ability to fully convert these instruments into common stock if it would push their beneficial ownership above 9.99%, potentially impacting their flexibility or future upside from these specific warrants.

Future Outlook

The document does not provide specific forward-looking statements or guidance regarding 89bio, Inc.'s future operations or financial performance, focusing solely on beneficial ownership disclosure.

Industry Context

This filing highlights the continued significant investment by RA Capital Management, a prominent healthcare-focused investment firm, in 89bio, Inc., a biopharmaceutical company. Such sustained large-scale institutional ownership is common in the biotech sector, where specialized funds often take substantial stakes in companies developing novel therapies, indicating a long-term strategic interest in the company's pipeline and market potential.

Comparison to Industry Standards

• This Schedule 13D/A filing is a standard regulatory disclosure for significant beneficial ownership. It does not contain information that allows for a direct comparison of 89bio, Inc.'s operational or financial results against specific comparable companies or industry benchmarks. The filing's purpose is to update ownership percentages, not to provide performance metrics.

Stakeholder Impact

• Shareholders: Provides transparency regarding the significant ownership stake held by RA Capital Management and its affiliates, confirming their continued investment in 89bio, Inc. The stability of the percentage ownership despite an increase in outstanding shares may reassure existing shareholders about institutional confidence.
• Company Management: Awareness of a large, stable institutional shareholder like RA Capital Management can influence strategic decisions and corporate governance, as such investors often engage with management.

Next Steps

• The document does not mention any specific future actions, events, or milestones for 89bio, Inc. or the Reporting Persons beyond the ongoing regulatory compliance.

Key Dates

Keywords

89bio Inc., RA Capital Management, Schedule 13D/A, Beneficial Ownership, Common Stock, Healthcare Investment, Biotechnology, Pre-funded Warrants, Institutional Investor