Sionna Therapeutics, Inc.
SION- Exchange
- Nasdaq
- Industry
- Pharmaceutical Preparations
- SEC CIK
- 0002036042
In the last 90 days, Sionna Therapeutics, Inc. insiders filed 0 open-market purchases and 4 sales; 146 institutions reported holding it in 13F filings for Q2 2026, worth $2.11B in total; Viking Global Investors is the only superinvestor holding it.
Holders of 5% or more of SION
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Sionna Therapeutics, Inc., largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| TPG GP A, LLC | 13D | 15.20%6.68M shares | New | Feb 18, 20251 filing | Feb 18, 2025 | SEC |
| Ra Capital Management, L.P. | 13D/A | 14.30%6.48M shares | −8.30 ppfrom 22.60% | Feb 18, 20253 filings | Sep 21, 2026 | SEC |
| Viking Global Investors LPSuperinvestorViking Global Investors | 13G/A | 7.10%3.20M shares | +0.40 ppfrom 6.70% | Feb 14, 20252 filings | May 15, 2026 | SEC |
| OrbiMed Advisors LLC | 13D/A | 6.60%2.97M shares | −1.80 ppfrom 8.40% | Feb 13, 20252 filings | Apr 20, 2026 | SEC |
| Enavate Sciences GP, LLC | 13D | 5.60%2.48M shares | New | Feb 18, 20251 filing | Feb 18, 2025 | SEC |
| Atlas Venture Fund XI, L.P. | 13D/A | 5.40%2.38M shares | −1.10 ppfrom 6.50% | Feb 18, 20252 filings | Oct 20, 2025 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
15 Schedule 13D and 13G filings on Sionna Therapeutics, Inc., newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| Sep 21, 20266:57 PM ET | Ra Capital Management, L.P.and 4 others | 13D/A | 14.30%6.48M shares | −8.30 ppfrom 22.60% | Sep 17, 2026 | SEC |
| May 15, 20265:48 PM ET | Viking Global Investors LPand 9 othersSuperinvestorViking Global Investors | 13G/A | 7.10%3.20M shares | +0.40 ppfrom 6.70% | Mar 31, 2026 | SEC |
| May 12, 20267:39 AM ET | Qatar Investment Authorityand 1 other | 13G/A | 4.50%2.02M shares | −0.50 ppfrom 5.00%Below 5% | Mar 31, 2026 | SEC |
| Apr 20, 20266:46 PM ET | OrbiMed Advisors LLCand 1 other | 13D/A | 6.60%2.97M shares | −1.80 ppfrom 8.40% | Apr 15, 2026 | SEC |
| Nov 7, 20254:59 PM ET | Ra Capital Management, L.P.and 4 others | 13D/A | 22.60%10.1M shares | −1.10 ppfrom 23.70% | Nov 5, 2025 | SEC |
| Oct 31, 20259:48 AM ET | JPMorgan Chase & Co | 13G/A | 4.40%1.98M shares | −0.60 ppfrom 5.00%Below 5% | Sep 30, 2025 | SEC |
| Oct 20, 20259:40 PM ET | Atlas Venture Fund XI, L.P.and 5 others | 13D/A | 5.40%2.38M shares | −1.10 ppfrom 6.50% | Oct 16, 2025 | SEC |
| Jul 30, 20251:19 PM ET | JPMorgan Chase & Co | 13G | 5.00%2.22M shares | New | Jun 30, 2025 | SEC |
| Jun 16, 20257:37 AM ET | Qatar Investment Authorityand 1 other | 13G | 5.00%2.21M shares | New | Jun 11, 2025 | SEC |
| Feb 18, 20258:56 PM ET | TPG GP A, LLCand 2 others | 13D | 15.20%6.68M shares | New | Feb 10, 2025 | SEC |
| Feb 18, 20254:59 PM ET | Atlas Venture Fund XI, L.P.and 5 others | 13D | 6.50%2.89M shares | New | Feb 10, 2025 | SEC |
| Feb 18, 20254:25 PM ET | Ra Capital Management, L.P.and 4 others | 13D | 23.70%10.4M shares | New | Feb 10, 2025 | SEC |
| Feb 18, 20254:22 PM ET | Enavate Sciences GP, LLCand 1 other | 13D | 5.60%2.48M shares | New | Feb 10, 2025 | SEC |
| Feb 14, 20254:58 PM ET | Viking Global Investors LPand 10 othersSuperinvestorViking Global Investors | 13G | 6.70%2.95M shares | New | Feb 10, 2025 | SEC |
| Feb 13, 20254:47 PM ET | OrbiMed Advisors LLCand 1 other | 13D | 8.40%3.70M shares | New | Feb 10, 2025 | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell Sionna Therapeutics, Inc. shares.
No Form 144 notices for Sionna Therapeutics, Inc. are on file.