Atlas Venture Fund XI, LP's Sale of Sionna Therapeutics, Inc. Common Stock

Atlas Venture Fund XI, LP has filed a Form 144 with the SEC, indicating its intention to sell 139,897 shares of Sionna Therapeutics, Inc. common stock. The shares were acquired through a private placement on March 4, 2024. The filing also details the sale of 546,370 shares over the past three months, with transactions occurring on multiple dates between September 29, 2025, and October 15, 2025. The aggregate market value of the shares to be sold is approximately $4,324,216.27. The filing was signed by Ommer Chohan on October 16, 2025, and the plan for the sale was adopted on February 25, 2025. The shares are listed on NASDAQ, and Merrill Lynch is the broker involved in the transactions.