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SION

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.

New
Increased
Maintained
Reduced
Closed

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%)

Holders
65
Holders Change
+18
Holders Change %
+38.3%
% of All Funds
0.86%
Holding in Top 10
4
Holding in Top 10 Change
+2
Holding in Top 10 Change %
+100%
% of All Funds
0.05%
New
26
Increased
18
Reduced
10
Closed
8
Calls
–
Puts
–
Net Calls
–
Net Calls Change
–

Top Buyers

Rank Fund Capital Flow
1
B
Braidwell
Connecticut
+$14.2M
2
BlackRock
BlackRock
New York
+$5.75M
3
Viking Global Investors
Viking Global Investors
Connecticut
+$3.18M
4
DM
Deerfield Management
New York
+$2.93M
5
Aberdeen Group
Aberdeen Group
United Kingdom
+$2.68M

Top Sellers

Rank Fund Capital Flow
1
DCM
Driehaus Capital Management
Illinois
-$3.21M
2
Citadel Advisors
Citadel Advisors
Florida
-$2.58M
3
ZP
Zimmer Partners
New York
-$2.48M
4
Millennium Management
Millennium Management
New York
-$2.16M
5
T. Rowe Price Associates
T. Rowe Price Associates
Maryland
-$1.77M
Name Holding Trade Value Shares
Change 		Change in
Stake
State Street
26
State Street
Massachusetts
$2.16M +$1.44M +110,118 +765%
RSCM
27
Rock Springs Capital Management
Maryland
$1.73M – – –
Charles Schwab
28
Charles Schwab
California
$1.61M +$369K +28,188 +44%
Northern Trust
29
Northern Trust
Illinois
$1.59M +$853K +65,068 +243%
DCM
30
Driehaus Capital Management
Illinois
$1.45M -$3.21M -245,039 -75%
WP
31
Woodline Partners
California
$1.39M – – –
UBS Group
32
UBS Group
Switzerland
$891K +$527K +40,221 +361%
Holocene Advisors
33
Holocene Advisors
New York
$868K – – –
TD Asset Management
34
TD Asset Management
Ontario, Canada
$867K -$70.8K -5,400 -10%
Goldman Sachs
35
Goldman Sachs
New York
$799K -$232K -17,693 -28%
Morgan Stanley
36
Morgan Stanley
New York
$764K +$525K +40,079 +1,017%
Manulife (Manufacturers Life Insurance)
37
Manulife (Manufacturers Life Insurance)
Ontario, Canada
$660K +$58.8K +4,489 +13%
Renaissance Technologies
38
Renaissance Technologies
New York
$451K +$341K +26,000 New
Bank of New York Mellon
39
Bank of New York Mellon
New York
$419K +$316K +24,131 New
Barclays
40
Barclays
United Kingdom
$399K +$302K +23,022 New
RhumbLine Advisers
41
RhumbLine Advisers
Massachusetts
$307K +$232K +17,670 New
BAM
42
Bosun Asset Management
Illinois
$295K +$222K +16,975 New
Polen Capital Management
43
Polen Capital Management
Florida
$295K +$222K +16,975 New
N
44
Nuveen
North Carolina
$278K +$210K +16,040 New
Susquehanna International Group
45
Susquehanna International Group
Pennsylvania
$257K +$194K +14,834 New
Millennium Management
46
Millennium Management
New York
$243K -$2.16M -165,038 -92%
Commonwealth Equity Services
47
Commonwealth Equity Services
Massachusetts
$243K +$184K +14,017 New
Deutsche Bank
48
Deutsche Bank
Germany
$166K +$126K +9,596 New
MIM
49
MetLife Investment Management
New Jersey
$139K +$105K +8,033 New
New York State Common Retirement Fund
50
New York State Common Retirement Fund
New York
$118K +$89.1K +6,800 New
1
2
3

SION Hedge Fund Activity: Q2 2025 in Review

65 of the 7,596 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.