Who owns SION?
Institutional ownership of Sionna Therapeutics Inc. from Form 13F, Q2 2026
147 institutional managers reported holding Sionna Therapeutics Inc. (SION) in Form 13F filings for Q2 2026, with 48,281,390 shares worth $2.1B. The largest reported holder was Ra Capital Management, L.p. Managers that filed both quarters added a net 2,637,933 shares (+5.8%). 34 opened new positions and 8 sold out.
- Funds holding
- 147
- Value held
- $2.1B
- New / sold out
- 34 / 8
- Net shares, same filers
- +5.8%
Holdings as of June 30, 2026, the end of Q2 2026. Managers have 45 days after a quarter ends to file Form 13F (by August 14, 2026 for Q2 2026), so positions may have changed since.
Largest holders of SION
| Fund | Value | Share of 13F holdings | Shares | Move |
|---|---|---|---|---|
| Ra Capital Management, L.p. | $436M | 20.5% | 9,905,045 | Unchanged |
| TPG GP A, LLC | $286M | 13.5% | 6,494,962 | Unchanged |
| Viking Global Investors LP | $141M | 6.6% | 3,195,181 | Unchanged |
| Atlas Venture Life Science Advisors, LLC | $132M | 6.2% | 2,995,602 | Unchanged |
| Orbimed Advisors LLC | $112M | 5.3% | 2,555,877 | Trimmed |
| Enavate Sciences GP, LLC | $109M | 5.1% | 2,478,030 | Unchanged |
| Adage Capital Partners GP, L.l.c. | $70.4M | 3.3% | 1,600,000 | Added |
| BlackRock, Inc. | $64.9M | 3.1% | 1,474,769 | Added |
| JPMorgan Chase & Co | $64.1M | 3.1% | 1,490,508 | Added |
| Jennison Associates LLC | $51.6M | 2.4% | 1,172,133 | Trimmed |
| Citadel Advisors LLC | $50.5M | 2.4% | 1,147,636 | Trimmed |
| Vanguard Capital Management LLC | $49.8M | 2.3% | 1,132,001 | Added |
| State Street Corp | $44.9M | 2.1% | 1,021,534 | Added |
| Perceptive Advisors LLC | $39.8M | 1.9% | 905,000 | Added |
| Deerfield Management Company, L.p. | $30.0M | 1.4% | 680,916 | Trimmed |
| Siren, L.L.C. | $26.9M | 1.3% | 610,515 | Added |
| Price T Rowe Associates Inc | $21.0M | 1.0% | 478,016 | Trimmed |
| Eventide Asset Management, LLC | $20.9M | 1.0% | 474,981 | Trimmed |
| Geode Capital Management, LLC | $20.1M | 0.9% | 457,145 | Added |
| Casdin Capital, LLC | $17.6M | 0.8% | 400,000 | New |
| Baker Bros. Advisors LP | $17.6M | 0.8% | 400,000 | Unchanged |
| Kalehua Capital Management LLC | $17.3M | 0.8% | 394,144 | Unchanged |
| Goldman Sachs Group Inc | $17.1M | 0.8% | 388,810 | Added |
| Driehaus Capital Management LLC | $17.0M | 0.8% | 385,447 | Added |
| Franklin Resources Inc | $12.8M | 0.6% | 290,113 | Added |
Share of 13F holdings is each fund's shares as a share of the 48,281,390 SION shares all 13F filers reported, not of shares outstanding.
Biggest buyers in Q2 2026
- Adage Capital Partners GP, L.l.c. Added+$63.8M
- Casdin Capital, LLC New+$17.6M
- Siren, L.L.C. Added+$13.7M
- Driehaus Capital Management LLC Added+$13.6M
- State Street Corp Added+$11.7M
- Perceptive Advisors LLC Added+$10.8M
- FMR LLC Added+$8.7M
- Artisan Partners Limited Partnership New+$8.3M
- Longaeva Partners L.P. Added+$8.1M
- BlackRock, Inc. Added+$7.9M
Biggest sellers in Q2 2026
- Orbimed Advisors LLC Trimmed-$42.9M
- Deerfield Management Company, L.p. Trimmed-$12.7M
- Aberdeen Group plc Trimmed-$12.3M
- Jennison Associates LLC Trimmed-$12.3M
- Price T Rowe Associates Inc Trimmed-$12.2M
- Eventide Asset Management, LLC Trimmed-$7.5M
- Sio Capital Management, LLC Trimmed-$7.3M
- Soleus Capital Management, L.P. Trimmed-$5.1M
- Point72 Asset Management, L.P. Trimmed-$3.8M
- Superstring Capital Management LP Trimmed-$3.4M
The change in shares since the quarter before, adjusted for stock splits and priced at the Q2 2026 value per share. Funds bought $247M and sold $133M; 57 added and 40 trimmed.
Schedule 13D and 13G filings on SION
Owners of more than 5% must file within days, so these can be newer than the 13F data.
- 2026-11-09GOLDMAN SACHS GROUP INC SCHEDULE 13G filed by Sionna Therapeutics Inc.Schedule 13G
- 2025-07-30JPMORGAN CHASE & CO SCHEDULE 13G filed by Sionna Therapeutics Inc.Schedule 13G
- 2025-06-16Qatar Investment Authority SCHEDULE 13G filed by Sionna Therapeutics Inc.Schedule 13G
- 2025-02-19TPG GP A, LLC SCHEDULE 13D filed by Sionna Therapeutics Inc.Schedule 13D
- 2025-02-18Atlas Venture Fund XI, L.P. SCHEDULE 13D filed by Sionna Therapeutics Inc.Schedule 13D
- 2025-02-18RA CAPITAL MANAGEMENT, L.P. SCHEDULE 13D filed by Sionna Therapeutics Inc.Schedule 13D
- 2025-02-18Enavate Sciences GP, LLC SCHEDULE 13D filed by Sionna Therapeutics Inc.Schedule 13D
- 2025-02-14VIKING GLOBAL INVESTORS LP SCHEDULE 13G filed by Sionna Therapeutics Inc.Schedule 13G
- 2025-02-13ORBIMED ADVISORS LLC SCHEDULE 13D filed by Sionna Therapeutics Inc.Schedule 13D
Questions about SION ownership
- Who owns SION stock?
- 147 institutional investment managers reported SION positions in their Form 13F filings for Q2 2026, holding 48,281,390 shares worth $2.1B in total. Ra Capital Management, L.p. reported the largest position.
- Are funds buying or selling SION?
- In Q2 2026, 34 managers opened new SION positions, 57 added, 40 trimmed and 8 sold out. Managers that filed in both quarters added a net 2,637,933 shares.
- How current is this SION institutional ownership data?
- It covers holdings as of the end of Q2 2026. Managers have 45 days after the quarter ends to file Form 13F (by August 14, 2026 for Q2 2026), so positions may have changed since.
From the SEC's Form 13F data sets for Q2 2026: every 13F holdings report, matched to SION by CUSIP. Options are left out. SION news and filings · SION insider trades · Top funds