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MBX

MBX Biosciences
MBX

118 hedge funds and large institutions have $836M invested in MBX Biosciences in 2025 Q3 according to their latest regulatory filings, with 39 funds opening new positions, 29 increasing their positions, 30 reducing their positions, and 9 closing their positions.

New
Increased
Maintained
Reduced
Closed

333% more first-time investments, than exits

New positions opened: 39 | Existing positions closed: 9

99% more capital invested

Capital invested by funds: $420M → $836M (+$416M)

34% more funds holding

Funds holding: 88 → 118 (+30)

32.04% more ownership

Funds ownership: 110.22% → 142.26% (+32%)

0% more funds holding in top 10

Funds holding in top 10: 3 → 3 (0)

3% less repeat investments, than reductions

Existing positions increased: 29 | Existing positions reduced: 30

47% less call options, than puts

Call options by funds: $15.3M | Put options by funds: $29M

Holders
118
Holders Change
+30
Holders Change %
+34.09%
% of All Funds
1.55%
Holding in Top 10
3
Holding in Top 10 Change
–
Holding in Top 10 Change %
–
% of All Funds
0.04%
New
39
Increased
29
Reduced
30
Closed
9
Calls
$15.3M
Puts
$29M
Net Calls
-$13.7M
Net Calls Change
-$12.9M

Top Buyers

Rank Fund Capital Flow
1
Wellington Management Group
Wellington Management Group
Massachusetts
+$34.2M
2
KCM
Kynam Capital Management
New Jersey
+$26.7M
3
Citadel Advisors
Citadel Advisors
Florida
+$13.3M
4
EC
EcoR1 Capital
California
+$13M
5
DTC
Deep Track Capital
Connecticut
+$12.9M

Top Sellers

Rank Fund Capital Flow
1
MB
MPM BioImpact
Massachusetts
-$14.8M
2
T. Rowe Price Associates
T. Rowe Price Associates
Maryland
-$5.24M
3
SSA
Schonfeld Strategic Advisors
New York
-$4.66M
4
Point72 Asset Management
Point72 Asset Management
Connecticut
-$4.63M
5
RCM
RA Capital Management
Massachusetts
-$4.31M
Name Holding Trade Value Shares
Change 		Change in
Stake
BBA
26
Baker Bros. Advisors
New York
$4.86M +$3.71M +277,777 New
SCM
27
Soleus Capital Management
Connecticut
$4.81M +$3.68M +275,000 New
OM
28
Opaleye Management
Massachusetts
$4.43M +$183K +13,681 +6%
LP
29
Longaeva Partners
Illinois
$3.93M +$3M +224,433 New
PHS
30
PFM Health Sciences
California
$3.88M +$2.96M +221,505 New
SAM
31
Sectoral Asset Management
Quebec, Canada
$3.41M +$41.1K +3,073 +2%
TAM
32
TFG Asset Management
Cayman Islands
$3.11M +$2.38M +177,840 New
Charles Schwab
33
Charles Schwab
California
$2.98M +$836K +62,523 +58%
AAA
34
Affinity Asset Advisors
New York
$2.89M +$2.21M +165,000 New
Northern Trust
35
Northern Trust
Illinois
$2.33M +$236K +17,671 +15%
TD Asset Management
36
TD Asset Management
Ontario, Canada
$2.08M -$702K -52,512 -31%
BGM
37
Burkehill Global Management
New York
$1.75M +$1.34M +100,000 New
ECM
38
ExodusPoint Capital Management
New York
$1.75M +$1.34M +100,000 New
Schroder Investment Management Group
39
Schroder Investment Management Group
United Kingdom
$1.5M +$1.12M +83,766 New
DCM
40
DAFNA Capital Management
California
$1.49M +$1.14M +85,000 New
Hudson Bay Capital Management
41
Hudson Bay Capital Management
Connecticut
$1.49M +$1.14M +85,000 New
M
42
Murchinson
Ontario, Canada
$1.4M +$1.07M +80,000 New
SC
43
Stempoint Capital
New York
$1.31M -$883K -66,021 -47%
PIM
44
Platinum Investment Management
Australia
$1.21M -$579K -43,315 -38%
Fidelity Investments
45
Fidelity Investments
Massachusetts
$1.21M +$102K +7,643 +12%
Manulife (Manufacturers Life Insurance)
46
Manulife (Manufacturers Life Insurance)
Ontario, Canada
$1.2M -$250K -18,721 -21%
UBS Group
47
UBS Group
Switzerland
$1.06M +$398K +29,758 +96%
EAM
48
Exome Asset Management
New York
$917K -$143K -10,674 -17%
AWA
49
Aaron Wealth Advisors
Illinois
$875K – – –
IC
50
Ikarian Capital
Texas
$841K +$643K +48,071 New
1
2
3 4 5

MBX Hedge Fund Activity: Q3 2025 in Review

118 of the 7,620 institutional investors tracked by Wall St. Rank reported a position in MBX Biosciences (MBX) for Q3 2025, worth a combined $836M — up 99% from $420M a quarter earlier.

Buyers outnumbered sellers: 39 funds opened new MBX positions and 9 closed out — a net gain of 30 holders — while 29 added to existing stakes and 30 trimmed.

The largest buyer was Wellington Management Group, adding an estimated $34.2M. The largest seller was MPM BioImpact, exiting entirely with an estimated $14.8M sold.

  • 118 institutional investors held MBX Biosciences (MBX) as of Q3 2025, up from 88 in Q2 2025.
  • Funds reported $836M of MBX Biosciences stock for Q3 2025, up 99% quarter-over-quarter.
  • 39 funds opened new MBX Biosciences positions in Q3 2025 and 9 closed out, a net change of +30 holders.
  • The largest MBX Biosciences buyer in Q3 2025 was Wellington Management Group, an estimated $34.2M added.
  • The largest MBX Biosciences seller in Q3 2025 was MPM BioImpact, an estimated $14.8M sold.

Based on aggregated 13F filings for Q3 2025.