Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in SION held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | RA CAPITAL MANAGEMENT, L.P. | 9.9M | $397.1M | 0.0% | 21.938% | 4.21% |
| 2 | TPG GP A, LLC | 6.5M | $260.4M | -3.7% | 14.385% | 7.08% |
| 3 | ORBIMED ADVISORS LLC | 3.5M | $141.5M | -0.9% | 7.820% | 2.98% |
| 4 | VIKING GLOBAL INVESTORS LP | 3.2M | $128.1M | 0.0% | 7.077% | 0.36% |
| 5 | Atlas Venture Life Science Advisors, LLC | 3.0M | $120.1M | 0.0% | 6.635% | 15.20% |
| 6 | Enavate Sciences GP, LLC | 2.5M | $99.3M | 0.0% | 5.488% | 28.26% |
| 7 | JENNISON ASSOCIATES LLC | 1.5M | $58.2M | +30.1% | 3.214% | 0.04% |
| 8 | BlackRock, Inc. | 1.3M | $52.0M | +0.3% | 2.870% | 0.00% |
| 9 | CITADEL ADVISORS LLC | 1.2M | $46.8M | +7.3% | 2.584% | 0.02% |
| 10 | VANGUARD CAPITAL MANAGEMENT LLC | 1.0M | $41.3M | β | 2.280% | 0.00% |
| 11 | DEERFIELD MANAGEMENT COMPANY, L.P. (SERIES C) | 971K | $38.9M | 0.0% | 2.150% | 0.46% |
| 12 | STATE STREET CORP | 756K | $30.3M | +9.1% | 1.675% | 0.00% |
| 13 | PERCEPTIVE ADVISORS LLC | 658K | $26.4M | -44.2% | 1.458% | 0.52% |
| 14 | EVENTIDE ASSET MANAGEMENT, LLC | 646K | $25.9M | +1.0% | 1.430% | 0.43% |
| 15 | abrdn plc | 564K | $22.6M | -32.8% | 1.249% | 0.04% |
| 16 | BAKER BROS. ADVISORS LP | 400K | $16.0M | 0.0% | 0.886% | 0.09% |
| 17 | GEODE CAPITAL MANAGEMENT, LLC | 390K | $15.6M | +2.6% | 0.864% | 0.00% |
| 18 | Siren, L.L.C. | 300K | $12.0M | 0.0% | 0.664% | 0.33% |
| 19 | Sio Capital Management, LLC | 294K | $11.8M | β | 0.652% | 1.70% |
| 20 | Soleus Capital Management, L.P. | 294K | $11.8M | +9.3% | 0.650% | 0.48% |
| 21 | GOLDMAN SACHS GROUP INC | 263K | $10.6M | +625.6% | 0.583% | 0.00% |
| 22 | Ensign Peak Advisors, Inc | 256K | $10.2M | +220.1% | 0.566% | 0.02% |
| 23 | Candriam Luxembourg S.C.A. | 237K | $9.5M | β | 0.524% | 0.05% |
| 24 | Kalehua Capital Management LLC | 197K | $7.9M | 0.0% | 0.436% | 6.66% |
| 25 | FRANKLIN RESOURCES INC | 175K | $7.0M | 0.0% | 0.389% | 0.00% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). β% of Fundβ shows how much of that investorβs total 13F portfolio is invested in SION β a direct measure of their conviction.
Filings activity in SION during Q1 2026, grouped by how each filer changed its position.
5 quarters of 13F filings Β· Ξ columns show change vs prior quarter
| Quarter | Inst. Holders | Ξ Holders | Ownership % | Ξ Ownership | Total 13F Value | Ξ Value |
|---|---|---|---|---|---|---|
| Q1 2026 | 121 | +21% | 106.75% | 2.60 pp | $1.73B | 2.4% |
| Q4 2025 | 100 | +30% | 109.35% | +32.82 pp | $1.77B | +43% |
| Q3 2025 | 77 | +17% | 76.53% | +31.02 pp | $1.24B | +68% |
| Q2 2025 | 66 | +38% | 45.51% | +19.39 pp | $738M | +74% |
| Q1 2025 | 48 | β | 26.12% | β | $424M | β |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Ξ columns compare to the immediately prior filed quarter.
Quick answers to the most common questions about buying SION stock.
Based on Q1 2026 13F filings, institutional ownership of Sionna Therapeutics, Inc. stands at 106.7%, held across 121 reporting institutions.
RA CAPITAL MANAGEMENT, L.P. is the largest reported institutional holder of SION, with approximately 9,905,045 shares worth $0.40B as of Q1 2026.
Yes β 2 widely-followed marquee investors appear among the top 25 institutional holders of SION, including VIKING GLOBAL INVESTORS LP, CITADEL ADVISORS LLC.
Our composite Smart Money Score for SION is 52 out of 100 (Neutral). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
33 institutions opened new positions in SION during Q1 2026, while 12 fully exited. 34 added to existing positions and 54 trimmed.
SION institutional ownership fell by 2.60 percentage points quarter-over-quarter, with a net change of +21 holders.
The top 10 institutions account for 77.7% of all reported 13F value in SION, and the top 25 account for 92.5%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.
Sionna Therapeutics, Inc. (SION) Institutional Ownership