Sionna Therapeutics (SION)
Develops NBD1-stabilizing and complementary CFTR modulators for cystic fibrosis.
$5.59
vs last close−0.43 (−7.23%)
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13F · 13D/G · Form 4
| Institutions | ≈ 106.37% | 48.09M shares | |
|---|---|---|---|
| 157 holders · as of Jun 30, 2026 · largest filers plus last quarter's tail | |||
| Insiders | 2.04% | 924.1K shares | |
| 4 holders · as of Sep 18, 2026 | |||
| Strategic holders | 8.17% | 3.69M shares | |
| 1 holder · as of Feb 10, 2025 | |||
| Adds to | 116.58% | ||
45.21M company shares as of Sep 23, 2026 · institutions as of Jun 30, 2026 · holders as of their latest filing
This quarter's institutional total failed a plausibility check; shown: the largest filers plus last quarter's remainder.
These groups come from separate filings that can overlap, so they add to 116.58%; nothing is left for Other.
13F, as of Jun 30, 2026
157 holders · 48.09M shares · 41 new positions · 98 increased · 40 reduced · 9 closed
| Holder | Shares | % outstanding | Chg q/q | Filed |
|---|---|---|---|---|
| Ra Capital Management, L.P. | 9.91M | 21.91% | 0 | Aug 14, 2026 |
| TPG GP A, LLC | 6.49M | 14.37% | 0 | Aug 14, 2026 |
| Viking Global Investors LP | 3.20M | 7.07% | 0 | Aug 14, 2026 |
| Atlas Venture Life Science Advisors, LLC | 3.00M | 6.63% | 0 | Aug 13, 2026 |
| Orbimed Advisors LLC | 2.56M | 5.65% | −974.8K | Aug 14, 2026 |
| Enavate Sciences GP, LLC | 2.48M | 5.48% | 0 | Aug 14, 2026 |
| Adage Capital Partners GP, L.L.C. | 1.60M | 3.54% | +1.45M | Aug 14, 2026 |
| JPMorgan Chase & Co | 1.49M | 3.30% | +25.5K | Aug 12, 2026 |
13D/G · 5% or more, as filed
| Holder | % of class | Shares | Form | Filed |
|---|---|---|---|---|
| TPG GP A, LLC | 15.20% | 6.68M | 13D | Feb 18, 2025 |
| Peter Kolchinskyincl. RA Capital Healthcare Fund, L.P., RA Capital Management, L.P. +2 more | 14.30% | 6.48M | 13D | Sep 21, 2026 |
| Viking Global Investors LP | 7.10% | 3.20M | 13G | May 15, 2026 |
| OrbiMed Capital GP VIII LLCincl. Orbimed Advisors LLC | 6.60% | 2.97M | 13D | Apr 20, 2026 |
| Sionna Aggregator, LPincl. Enavate Sciences GP, LLC | 5.60% | 2.48M | 13D | Feb 18, 2025 |
| Atlas Venture Associates XI, LLCincl. Atlas Venture Opportunity Fund II, L.P., Atlas Venture Associates Opportunity II, LLC +3 more | 5.40% | 2.38M | 13D | Oct 20, 2025 |
Form 4
Latest trades
| Date | Insider | Type | Shares | Avg price | Owned after |
|---|---|---|---|---|---|
| Sep 17, 2026 | Ra Capital Management, L.P.director, 10 percent owner: | Sale · 2 lots | 3,448,811 | $6.33 | 3,448,812 |
| Jul 7, 2026 | Orbimed Advisors LLCdirector | Sale | 85,918 | $44.86 | 2,469,959 |
| Jul 7, 2026 | Peter A. Thompsondirector | Sale | 85,918 | $44.86 | 2,469,959 |
| Jul 6, 2026 | Jennifer Fitzpatrickofficer: Chief Legal Officer | Sale | 10,250 | $43.60 | 0 |
| Jun 30, 2026 | Orbimed Advisors LLCdirector | Sale | 115,844 | $45.50 | 2,555,877 |
| Jun 30, 2026 | Peter A. Thompsondirector | Sale | 115,844 | $45.50 | 2,555,877 |
| May 27, 2026 | Orbimed Advisors LLCdirector | Sale | 101 | $44.49 | 2,671,721 |
| May 27, 2026 | Peter A. Thompsondirector | Sale | 101 | $44.49 | 2,671,721 |
| May 11, 2026 | Orbimed Advisors LLCdirector | Sale | 184,639 | $46.22 | 2,671,822 |
| May 8, 2026 | Orbimed Advisors LLCdirector | Sale | 59,767 | $44.58 | 2,856,461 |
House and Senate disclosures
Not reported.