Sionna Therapeutics, Inc. - Ownership Filing by Chief Business Officer

The filing is a Form 3 submitted by Sionna Therapeutics, Inc. (CIK: 0002036042, Trading Symbol: SION) on October 3, 2025. It reports the ownership details of Caroline Stark Beer, the Chief Business Officer of the company. The filing indicates that Caroline Stark Beer does not own any securities of the company as of the period of report, which is October 1, 2025. The filing was signed by Jennifer Fitzpatrick as Attorney-in-Fact. The address of the reporting owner is listed as C/O Sionna Therapeutics, Inc., 21 Hickory Drive, Suite 500, Waltham, MA 02451.