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SION

Sionna Therapeutics
SION

47 hedge funds and large institutions have $434M invested in Sionna Therapeutics in 2025 Q1 according to their latest regulatory filings, with 47 funds opening new positions, increasing their positions, reducing their positions, and closing their positions.

New
Increased
Maintained
Reduced
Closed

94.04% more ownership

Funds ownership: 0% → 94.04% (+94%)

Holders
47
Holders Change
+47
Holders Change %
–
% of All Funds
0.63%
Holding in Top 10
2
Holding in Top 10 Change
+2
Holding in Top 10 Change %
% of All Funds
0.03%
New
47
Increased
–
Reduced
–
Closed
–
Calls
–
Puts
–
Net Calls
–
Net Calls Change
–

Top Buyers

Rank Fund Capital Flow
1
RCM
RA Capital Management
Massachusetts
+$171M
2
TGA
TPG GP A
Texas
+$109M
3
O
OrbiMed
New York
+$60.5M
4
AVLSA
Atlas Venture Life Science Advisors
Massachusetts
+$60.4M
5
Viking Global Investors
Viking Global Investors
Connecticut
+$48.2M

Top Sellers

No sellers this quarter
Name Holding Trade Value Shares
Change 		Change in
Stake
RCM
1
RA Capital Management
Massachusetts
$109M +$171M +10,445,322 New
TGA
2
TPG GP A
Texas
$69.9M +$109M +6,684,962 New
O
3
OrbiMed
New York
$38.8M +$60.5M +3,704,959 New
AVLSA
4
Atlas Venture Life Science Advisors
Massachusetts
$38.6M +$60.4M +3,694,020 New
Viking Global Investors
5
Viking Global Investors
Connecticut
$30.9M +$48.2M +2,952,754 New
ES
6
Enavate Sciences
California
$25.9M +$40.5M +2,478,030 New
JP Morgan Chase
7
JP Morgan Chase
New York
$22.7M +$35.5M +2,169,599 New
PA
8
Perceptive Advisors
New York
$13.1M +$20.4M +1,251,101 New
T. Rowe Price Associates
9
T. Rowe Price Associates
Maryland
$10.4M +$16.3M +996,212 New
Jennison Associates
10
Jennison Associates
New York
$8.99M +$14.1M +859,927 New
DM
11
Deerfield Management
New York
$7.81M +$12.2M +747,000 New
Aberdeen Group
12
Aberdeen Group
United Kingdom
$7.8M +$12.2M +745,964 New
Vanguard Group
13
Vanguard Group
Pennsylvania
$5.71M +$8.92M +546,167 New
Franklin Resources
14
Franklin Resources
California
$5.23M +$8.17M +500,023 New
BBA
15
Baker Bros. Advisors
New York
$4.18M +$6.54M +400,000 New
DCM
16
Driehaus Capital Management
Illinois
$3.44M +$5.37M +328,889 New
Citadel Advisors
17
Citadel Advisors
Florida
$3.42M +$5.33M +326,500 New
SL
18
Siren LLC
Connecticut
$3.4M +$5.31M +325,000 New
SCM
19
Soleus Capital Management
Connecticut
$2.51M +$3.92M +240,000 New
ZP
20
Zimmer Partners
New York
$2.48M +$3.88M +237,500 New
Ameriprise
21
Ameriprise
Minnesota
$2.19M +$3.42M +209,266 New
BlackRock
22
BlackRock
New York
$2.08M +$3.24M +198,396 New
Alyeska Investment Group
23
Alyeska Investment Group
Illinois
$1.95M +$3.04M +186,222 New
Millennium Management
24
Millennium Management
New York
$1.87M +$2.93M +179,072 New
Geode Capital Management
25
Geode Capital Management
Massachusetts
$1.42M +$2.22M +135,563 New
1
2

SION Hedge Fund Activity: Q1 2025 in Review

47 of the 7,459 institutional investors tracked by Wall St. Rank reported a position in Sionna Therapeutics (SION) for Q1 2025, worth a combined $434M.

Buyers outnumbered sellers: 47 funds opened new SION positions and 0 closed out — a net gain of 47 holders — while 0 added to existing stakes and 0 trimmed.

The largest buyer was RA Capital Management, opening a new position worth an estimated $171M.

  • 47 institutional investors held Sionna Therapeutics (SION) as of Q1 2025, up from 0 in Q4 2024.
  • Funds reported $434M of Sionna Therapeutics stock for Q1 2025.
  • 47 funds opened new Sionna Therapeutics positions in Q1 2025 and 0 closed out, a net change of +47 holders.
  • The largest Sionna Therapeutics buyer in Q1 2025 was RA Capital Management, an estimated $171M added.

Based on aggregated 13F filings for Q1 2025.