Sionna Therapeutics SION Insider Ownership

Updated Oct 11, 2026

Over the past 12 months, Sionna Therapeutics insiders sold $132.21 million of stock on the open market (6.18Mn shares) and made no open-market purchases.

• Counted by insider, open-market selling of SION stock in the past 12 months came from 7 insiders, with no insider buying.
• The largest open-market sales of SION in the past 12 months were by Orbimed Advisors LLC (Director), totaling $49.29 million (1.09Mn shares), most recently on July 7, 2026.
• Sionna Therapeutics' latest insider trade on the open market was a sale of 3.45Mn shares for $21.84 million by Ra Capital Management, L.P. (Director and 10% owner) on September 17, 2026.
• Beyond open-market trades, insiders at Sionna Therapeutics received 468.85K shares in stock awards and acquired 155.75K shares through option exercises and conversions in the last 12 months.
• Per Business Quant, SION insiders together hold 16.49Mn shares based on their latest Form 4 filings, or 36.52% of the 45.16Mn shares outstanding; that total is down 2.85% from 16.98Mn shares at the end of Q3 2025.
• By type of ownership, SION insiders hold 6.57% of their shares directly (1.08Mn shares) and 93.43% indirectly (15.41Mn shares).
• Holdings in Sionna Therapeutics stock are reported by 8 insiders, the officers, directors and 10% owners who have filed a Form 4 in the past two years.
• Sionna Therapeutics' three largest insider shareholders, based on their latest Form 4 filings, are TPG GP A, LLC (10% owner, 6.49Mn shares), Ra Capital Management, L.P. (Director and 10% owner, 3.45Mn shares) and Bruce Booth (Director, 3Mn shares).
• TPG GP A, LLC holds 39.38% of the combined insider position in Sionna Therapeutics.
• A total of 51 Form 4 filings with transactions in Sionna Therapeutics stock were made over the past 12 months, by 16 insiders.
• The insider holdings and trades above for Sionna Therapeutics reflect Form 4 filings through September 21, 2026.