SCHEDULE: Avidity Partners Cuts Dianthus Therapeutics Stake Below 5%

Avidity Partners Management LP and its affiliates have reduced their beneficial ownership in Dianthus Therapeutics, Inc. to below 5%, filing an exit amendment to their Schedule 13D.

Summary

• Avidity Partners Management LP and its affiliated entities, including Avidity Private Master Fund I LP and Michael Gregory, have filed an Amendment No. 3 to Schedule 13D for Dianthus Therapeutics, Inc.
• The filing reports a greater than 1.00% decrease in the percentage of Common Stock beneficially owned by the Reporting Persons.
• The decrease is due to the sale of shares of Common Stock by private investment funds managed by Avidity Partners Management LP.
• As a result of these sales, the Reporting Persons no longer beneficially own 5% or more of the total outstanding shares of Dianthus Therapeutics, Inc. Common Stock.
• This Amendment No. 3 serves as an 'exit filing' for the Reporting Persons, indicating they are no longer required to file Schedule 13D amendments for this stake.
• The aggregate amount beneficially owned by Avidity Partners Management LP and related entities is 2,104,184 shares, representing 4.9% of the class.
• Avidity Private Master Fund I LP beneficially owns 1,899,593 shares, representing 4.4% of the class.
• The percentage ownership is based on 42,876,015 shares of Common Stock outstanding as of November 3, 2025, as reported in the Issuer's Form 10-Q filed on November 5, 2025.
• Funds used for the acquisition of shares came from the working capital of private funds advised by Avidity Partners Management LP.

Sentiment

Score: 3

Explanation: The sentiment is negative as a significant institutional investor has reduced its stake below the 5% threshold, signaling a potential lack of conviction or a strategic exit. This action typically implies a bearish outlook from the selling entity.

Negatives

• A significant institutional investor group, Avidity Partners, has reduced its stake in Dianthus Therapeutics, Inc. to below the 5% reporting threshold, signaling a potential decrease in conviction or a strategic exit.
• The sales occurred at prices ranging from approximately $40.00 to $43.35 per share, indicating the investor chose to divest at these levels.

Risks

• The Reporting Persons reserve the right to acquire or dispose of additional shares of Common Stock in the future, which could introduce further volatility to the stock price.
• The exit of a significant institutional holder may be perceived negatively by the market, potentially impacting investor sentiment and share price.

Future Outlook

The Reporting Persons state that they may, from time to time, acquire or dispose of additional shares of Common Stock, consistent with their investment purpose. They have no present plans or proposals for corporate actions concerning the Issuer, but reserve the right to change their intentions.

Industry Context

This filing reflects a specific investment firm's portfolio adjustment rather than a broader industry trend. The divestment by a significant holder could be interpreted within the context of the biotechnology or pharmaceutical sector's inherent volatility and investment cycles, where investors frequently re-evaluate positions based on clinical trial progress, market conditions, or strategic shifts.

Stakeholder Impact

• Shareholders: Existing shareholders may experience negative sentiment and potential downward pressure on the stock price due to the divestment by a significant institutional investor.
• Potential Investors: May view the reduction in stake by Avidity Partners as a cautionary signal, influencing their investment decisions.

Next Steps

• The Reporting Persons may, from time to time, acquire or dispose of additional shares of Common Stock in the open market, privately negotiated transactions, or otherwise.
• This Amendment No. 3 is the final amendment to the Schedule 13D for these Reporting Persons, as they no longer beneficially own 5% or more of the total outstanding shares.

Key Dates

Recommendation

The filing indicates a significant institutional investor, Avidity Partners, has reduced its stake in Dianthus Therapeutics to below the 5% threshold, effectively exiting its Schedule 13D reporting requirement. This action, particularly the sale of a substantial number of shares, typically signals a lack of conviction or a strategic divestment by a major holder. For a seasoned investor, this would generally be interpreted as a bearish signal, suggesting a 'sell' recommendation for existing positions or avoiding new positions, as the departure of a large investor can lead to negative market sentiment and potential downward pressure on the stock price.

Keywords

Dianthus Therapeutics, Avidity Partners, Schedule 13D, Beneficial Ownership, Institutional Investor, Stock Sales, Exit Filing, Common Stock, Investment Management