SION
Sionna Therapeutics, Inc. · Healthcare · Biotechnology
Momentum inputs (comparable managers):
holder breadth -10.0% ·
share flow +0.2% ·
net new positions -11.1%
— formula
Concentrated accumulation — rising shares among fewer holders
All ownership figures: tracked 13F managers only, common-stock positions, reporting period Q2 2025
| # | Manager | Shares | Δ shares | Value | Their weight | Held | ||
|---|---|---|---|---|---|---|---|---|
| 1 | Viking Global Investors ✦ | 3.20M | +8.2% | $55.44M | 0.2% | ▲ Add | 2 | SEC ↗ |
| 2 | T. Rowe Price ✦ | 861.24K | -13.6% | $14.94M | 0.0% | ▼ Trim | 2 | SEC ↗ ×2 |
| 3 | BlackRock ✦ (passive) | 637.10K | — | $11.05M | 0.0% | n/c | 1 | SEC ↗ ×5 |
| 4 | The Vanguard Group ✦ (passive) | 630.35K | — | $10.94M | 0.0% | n/c | 1 | SEC ↗ ×3 |
| 5 | Geode Capital Management ✦ (passive) | 289.27K | +113.4% | $5.02M | 0.0% | ▲ Add | 2 | SEC ↗ ×2 |
| 6 | Citadel Advisors ✦ | 129.91K | -60.2% | $2.25M | 0.0% | ▼ Trim | 2 | SEC ↗ |
| 7 | State Street Global Advisors ✦ (passive) | 124.52K | +764.7% | $2.16M | 0.0% | ▲ Add | 2 | SEC ↗ |
| 8 | Renaissance Technologies ✦ | 26.00K | New | $451,100 | 0.0% | New | 1 | SEC ↗ |
| 9 | Millennium Management ✦ | 14.03K | -92.2% | $243,490 | 0.0% | ▼ Trim | 2 | SEC ↗ |
“Their weight” = the position's share of that manager's reported 13F equity value — the conviction measure. ✦ = curated manager.
New buyers
| Renaissance Technologies | $451,100 | 0.0% |
Exited
| Marshall Wace | $127,486 | was 0.0% |
| Two Sigma Investments | $122,539 | was 0.0% |
Full-market context: across ALL 13F filers (SEC structured data, Q1 2026): 121 holders, 43.94M shares, $1.73B reported. This is a different, older period than the tracked-universe figures above and the two are never mixed.
What else this security's tracked holders most often hold — shared-ownership counts, not fundamental relationships.
Open-market purchases (P)
No open-market insider purchases in our coverage window.
Open-market sales (S)
Director, 10% owner · 3.42M sh · $21.58M
Director, 10% owner · 33.80K sh · $252,148
Awards, exercises and tax withholding are never counted as buys or sales here. Methodology
14.3% of class · View original SEC filing ↗