Sionna Therapeutics
SION
65 hedge funds and large institutions have $754M invested in Sionna Therapeutics in 2025 Q2 according to their latest regulatory filings, with 26 funds opening new positions, 18 increasing their positions, 10 reducing their positions, and 8 closing their positions.
225% more first-time investments, than exits
New positions opened: 26 | Existing positions closed: 8
100% more funds holding in top 10
Funds holding in top 10: 2 → 4 (+2)
80% more repeat investments, than reductions
Existing positions increased: 18 | Existing positions reduced: 10
74% more capital invested
Capital invested by funds: $434M → $754M (+$320M)
38% more funds holding
Funds holding: 47 → 65 (+18)
4.42% more ownership
Funds ownership: 94.04% → 98.47% (+4.4%)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
B
Braidwell
Stamford,
Connecticut
|
+$14.2M |
| 2 |
BlackRock
New York
|
+$5.75M |
| 3 |
Viking Global Investors
Stamford,
Connecticut
|
+$3.18M |
| 4 |
DM
Deerfield Management
New York
|
+$2.93M |
| 5 |
Aberdeen Group
Edinburgh,
United Kingdom
|
+$2.68M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
DCM
Driehaus Capital Management
Chicago,
Illinois
|
-$3.21M |
| 2 |
Citadel Advisors
Miami,
Florida
|
-$2.58M |
| 3 |
ZP
Zimmer Partners
New York
|
-$2.48M |
| 4 |
Millennium Management
New York
|
-$2.16M |
| 5 |
T. Rowe Price Associates
Baltimore,
Maryland
|
-$1.77M |
SION Hedge Fund Activity: Q2 2025 in Review
65 of the 7,613 institutional investors tracked by Wall St. Rank reported a position in Sionna Therapeutics (SION) for Q2 2025, worth a combined $754M — up 74% from $434M a quarter earlier.
Buyers outnumbered sellers: 26 funds opened new SION positions and 8 closed out — a net gain of 18 holders — while 18 added to existing stakes and 10 trimmed.
The largest buyer was Braidwell, opening a new position worth an estimated $14.2M. The largest seller was Driehaus Capital Management, cutting an estimated $3.21M.
- 65 institutional investors held Sionna Therapeutics (SION) as of Q2 2025, up from 47 in Q1 2025.
- Funds reported $754M of Sionna Therapeutics stock for Q2 2025, up 74% quarter-over-quarter.
- 26 funds opened new Sionna Therapeutics positions in Q2 2025 and 8 closed out, a net change of +18 holders.
- The largest Sionna Therapeutics buyer in Q2 2025 was Braidwell, an estimated $14.2M added.
- The largest Sionna Therapeutics seller in Q2 2025 was Driehaus Capital Management, an estimated $3.21M sold.
Based on aggregated 13F filings for Q2 2025.