Sionna Therapeutics
SION
101 hedge funds and large institutions have $1.81B invested in Sionna Therapeutics in 2025 Q4 according to their latest regulatory filings, with 30 funds opening new positions, 39 increasing their positions, 20 reducing their positions, and 7 closing their positions.
329% more first-time investments, than exits
New positions opened: 30 | Existing positions closed: 7
95% more repeat investments, than reductions
Existing positions increased: 39 | Existing positions reduced: 20
75% more funds holding in top 10
Funds holding in top 10: 4 → 7 (+3)
44% more capital invested
Capital invested by funds: $1.26B → $1.81B (+$548M)
29% more funds holding
Funds holding: 78 → 101 (+23)
1.42% more ownership
Funds ownership: 97.06% → 98.48% (+1.4%)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Citadel Advisors
Miami,
Florida
|
+$39.9M |
| 2 |
EAM
Eventide Asset Management
Boston,
Massachusetts
|
+$24.2M |
| 3 |
State Street
Boston,
Massachusetts
|
+$17.2M |
| 4 |
BlackRock
New York
|
+$16.9M |
| 5 |
T. Rowe Price Associates
Baltimore,
Maryland
|
+$7.34M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
JP Morgan Chase
New York
|
-$28.3M |
| 2 |
AVLSA
Atlas Venture Life Science Advisors
Cambridge,
Massachusetts
|
-$23.5M |
| 3 |
RCM
RA Capital Management
Boston,
Massachusetts
|
-$20.5M |
| 4 |
B
Braidwell
Stamford,
Connecticut
|
-$9.24M |
| 5 |
SCM
Soleus Capital Management
Greenwich,
Connecticut
|
-$5.5M |
| Name | Holding | Trade Value |
Shares Change |
Change in Stake |
|
|---|---|---|---|---|---|
|
RIL
101
Rothschild Investment LLC
Chicago,
Illinois
| $41 | +$38 | +1 | New |
|
|
B
102
Braidwell
Stamford,
Connecticut
| – | -$9.24M | -314,013 | Closed |
|
103
Holocene Advisors
New York
| – | -$1.47M | -50,000 | Closed |
|
104
Marshall Wace
London,
United Kingdom
| – | -$885K | -30,103 | Closed |
|
105
Renaissance Technologies
New York
| – | -$429K | -14,600 | Closed |
|
|
JG
106
Jain Global
New York
| – | -$250K | -8,513 | Closed |
|
107
Federated Hermes
Pittsburgh,
Pennsylvania
| – | -$3.32K | -113 | Closed |
|
|
AAP
108
Arax Advisory Partners
Denver,
Colorado
| – | -$2.71K | -92 | Closed |
|
SION Hedge Fund Activity: Q4 2025 in Review
101 of the 8,223 institutional investors tracked by Wall St. Rank reported a position in Sionna Therapeutics (SION) for Q4 2025, worth a combined $1.81B — up 44% from $1.26B a quarter earlier.
Buyers outnumbered sellers: 30 funds opened new SION positions and 7 closed out — a net gain of 23 holders — while 39 added to existing stakes and 20 trimmed.
The largest buyer was Citadel Advisors, adding an estimated $39.9M. The largest seller was JP Morgan Chase, cutting an estimated $28.3M.
- 101 institutional investors held Sionna Therapeutics (SION) as of Q4 2025, up from 78 in Q3 2025.
- Funds reported $1.81B of Sionna Therapeutics stock for Q4 2025, up 44% quarter-over-quarter.
- 30 funds opened new Sionna Therapeutics positions in Q4 2025 and 7 closed out, a net change of +23 holders.
- The largest Sionna Therapeutics buyer in Q4 2025 was Citadel Advisors, an estimated $39.9M added.
- The largest Sionna Therapeutics seller in Q4 2025 was JP Morgan Chase, an estimated $28.3M sold.
Based on aggregated 13F filings for Q4 2025.