Sionna Therapeutics, Inc. (SION) Institutional Ownership

Ownership Summary

According to SEC filings for the period ending September 2025, Sionna Therapeutics, Inc. (NASDAQ:SION) is held by 78 institutional firms.

• Institutional ownership in Sionna Therapeutics edged down to 97.1% in September 2025, compared to 98.2% in June 2025.
• Quarterly data indicates a -1.39% shift in institutional share volume, and the annual owner count reflects an unavailable change.
• The latest 13F cycle for Sionna Therapeutics reveals that of 78 total investors, 38 funds grew their exposure, whereas 22 reduced theirs and 18 made no changes.
• This class of investors decreased its holdings in Sionna Therapeutics to 42.84Mn shares for the 13F-cycle ending September 2025, down by 602.00K shares quarter on quarter, and down N/A shares year over year.
• The top institutional stake in Sionna Therapeutics as of September 30, 2025 belongs to RA CAPITAL MANAGEMENT, L.P., which owns 10.45Mn shares, or 23.66% of the company.
• Among the most significant buyers of Sionna Therapeutics during September 2025 were VANGUARD GROUP INC (512.80K), JENNISON ASSOCIATES LLC (244.57K), BlackRock, Inc. (207.50K), MILLENNIUM MANAGEMENT LLC (200.05K), STATE STREET CORP (115.68K).
• Leading sellers of Sionna Therapeutics stock in September 2025 included BRAIDWELL LP (767.84K), CITADEL ADVISORS LLC (290.58K), FRANKLIN RESOURCES INC (257.88K), JPMORGAN CHASE & CO (242.56K), PRICE T ROWE ASSOCIATES INC /MD/ (223.48K).
• The top 10 institutional holders of Sionna Therapeutics for the quarter ending September 2025 included RA CAPITAL MANAGEMENT, L.P. (10.45Mn), TPG GP A, LLC (6.74Mn), ORBIMED ADVISORS LLC (3.70Mn), Atlas Venture Life Science Advisors, LLC (3.62Mn), VIKING GLOBAL INVESTORS LP (3.20Mn), Enavate Sciences GP, LLC (2.48Mn), JPMORGAN CHASE & CO (1.98Mn), PERCEPTIVE ADVISORS LLC (1.18Mn), VANGUARD GROUP INC (1.14Mn), JENNISON ASSOCIATES LLC (997.38K).