SCHEDULE: Sofinnova Reduces Abivax Stake to 5.6%

Sofinnova Crossover I SLP and related entities have reduced their beneficial ownership in Abivax SA to approximately 5.6% of outstanding ordinary shares through recent ADS sales.

Summary

• Sofinnova Crossover I SLP and its related reporting persons filed an Amendment No. 3 to their Schedule 13D for Abivax SA.
• The filing reports sales of American Depositary Shares (ADS) of Abivax SA on October 28 and October 29, 2025.
• On October 28, 2025, 522,948 ADSs were sold at a weighted average price of $94.00, and an additional 67,929 ADSs were sold at a weighted average price of $95.42.
• On October 29, 2025, 606,293 ADSs were sold at a weighted average price of $94.00, and an additional 2,830 ADSs were sold at a weighted average price of $95.34.
• As of October 29, 2025, Sofinnova Crossover I SLP directly held 4,334,739 Ordinary Shares, representing approximately 5.6% of Abivax SA's outstanding Ordinary Shares.
• This stake corresponds to 8,399,478 voting rights, or approximately 9.4% of the Issuer's outstanding voting rights.
• The ownership percentages are based on 77,830,067 Ordinary Shares and 89,189,666 voting rights outstanding as of September 30, 2025.

Sentiment

Score: 3

Explanation: The sentiment is negative due to a significant institutional investor reducing its stake in the company, which can be interpreted as a lack of conviction or profit-taking, potentially signaling future challenges or a re-evaluation of the company's prospects.

Negatives

• Sofinnova Crossover I SLP and related entities significantly reduced their beneficial ownership in Abivax SA through open market sales.
• The sales occurred over two consecutive days, indicating a deliberate reduction in exposure by a major institutional investor.

Risks

• The Reporting Persons retain the right to sell or otherwise dispose of all or part of their beneficially owned shares, which could lead to further downward pressure on the stock price.

Future Outlook

The Reporting Persons may consider matters related to their investment, formulate plans, and engage in discussions with Abivax SA's management or board regarding their investment. They retain the right to acquire additional shares or dispose of existing holdings.

Industry Context

This filing reflects a significant institutional investor, Sofinnova, reducing its stake in a biotechnology company, Abivax SA. Such reductions can occur for various reasons, including portfolio rebalancing, profit-taking, or a change in investment thesis regarding the company's prospects or the broader biotech market. Without further context on Abivax's recent performance or industry trends, it's difficult to pinpoint the exact driver, but it signals a shift in this specific investor's position.

Comparison to Industry Standards

• This filing is a disclosure of a change in beneficial ownership by an institutional investor and does not contain performance metrics of Abivax SA that would allow for a direct comparison to industry standards or specific comparable companies/projects.
• The action itself (reducing a stake) is a common occurrence in investment portfolios, but the specific reasons for Sofinnova's divestment are not detailed here, making direct comparative assessment challenging.

Legal Proceedings

• None of the Reporting Persons have been convicted in any criminal proceeding (excluding traffic violations or similar misdemeanors) in the last five years.
• None of the Reporting Persons have been a party to a civil proceeding resulting in a judgment, decree, or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws in the last five years.

Stakeholder Impact

• Shareholders: The reduction in a significant institutional investor's stake could lead to negative market sentiment and potential downward pressure on the share price.

Next Steps

• The Reporting Persons may consider acquiring additional Ordinary Shares or other securities of Abivax SA.
• The Reporting Persons may sell or otherwise dispose of all or part of their beneficially owned shares.
• The Reporting Persons may engage in ordinary course transactions with financial institutions regarding Abivax SA securities.
• The Reporting Persons may formulate plans or hold discussions with Abivax SA management or board regarding their investment.

Key Dates

Recommendation

The significant reduction in beneficial ownership by a major institutional investor like Sofinnova Crossover I SLP, as detailed in this Schedule 13D amendment, typically signals a negative outlook or a strategic divestment. While the specific reasons for the sale are not disclosed, such an action by a sophisticated investor often precedes or reflects a re-evaluation of the company's prospects, potentially leading to decreased investor confidence and downward pressure on the stock price. For a seasoned investor, this would warrant a re-evaluation of their own position, with a 'sell' recommendation being prudent given the potential for negative market reaction and the implied lack of conviction from a key holder.

Keywords

Abivax SA, Sofinnova Crossover I SLP, Sofinnova Partners SAS, Schedule 13D, Beneficial Ownership, ADS sales, Shareholding reduction, Biotechnology investment, Institutional investor