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MBX

MBX Biosciences
MBX

138 hedge funds and large institutions have $1.53B invested in MBX Biosciences in 2025 Q4 according to their latest regulatory filings, with 45 funds opening new positions, 53 increasing their positions, 25 reducing their positions, and 25 closing their positions.

New
Increased
Maintained
Reduced
Closed

133% more funds holding in top 10

Funds holding in top 10: 3 → 7 (+4)

112% more repeat investments, than reductions

Existing positions increased: 53 | Existing positions reduced: 25

83% more capital invested

Capital invested by funds: $836M → $1.53B (+$691M)

80% more first-time investments, than exits

New positions opened: 45 | Existing positions closed: 25

17% more funds holding

Funds holding: 118 → 138 (+20)

34.4% less ownership

Funds ownership: 142.26% → 107.85% (-34%)

71% less call options, than puts

Call options by funds: $4.09M | Put options by funds: $14M

Holders
138
Holders Change
+20
Holders Change %
+16.95%
% of All Funds
1.68%
Holding in Top 10
7
Holding in Top 10 Change
+4
Holding in Top 10 Change %
+133.33%
% of All Funds
0.09%
New
45
Increased
53
Reduced
25
Closed
25
Calls
$4.09M
Puts
$14M
Net Calls
-$9.9M
Net Calls Change
+$3.75M

Top Buyers

1
B
Braidwell
Connecticut
+$24.7M
2
BlackRock
BlackRock
New York
+$23.3M
3
EAM
Eventide Asset Management
Massachusetts
+$21.6M
4
D.E. Shaw & Co
D.E. Shaw & Co
New York
+$16.3M
5
State Street
State Street
Massachusetts
+$8.58M

Top Sellers

1
Wellington Management Group
Wellington Management Group
Massachusetts
-$35.8M
2
KCM
Kynam Capital Management
New Jersey
-$25.8M
3
Franklin Resources
Franklin Resources
California
-$22.9M
4
WP
Woodline Partners
California
-$4.88M
5
BBA
Baker Bros. Advisors
New York
-$4.86M
Name Holding Trade Value Shares
Change 		Change in
Stake
Goldman Sachs
26
Goldman Sachs
New York
$10.5M -$635K -26,183 -7%
TECP
27
Trails Edge Capital Partners
Georgia
$9.94M +$7.65M +315,158 New
RSCM
28
Rock Springs Capital Management
Maryland
$8.91M – – –
UBS Group
29
UBS Group
Switzerland
$8.87M +$5.35M +220,487 +363%
OM
30
Opaleye Management
Massachusetts
$8.2M +$170K +7,000 +3%
AAA
31
Affinity Asset Advisors
New York
$7.88M +$2.06M +85,000 +52%
Charles Schwab
32
Charles Schwab
California
$7.01M +$1.27M +52,174 +31%
GIM
33
Goelzer Investment Management
Indiana
$6.99M +$5.38M +221,672 New
EC
34
Elmind Capital
New York
$6.65M +$5.12M +211,000 New
Northern Trust
35
Northern Trust
Illinois
$6.02M +$1.4M +57,616 +43%
SSA
36
Schonfeld Strategic Advisors
New York
$5.27M -$2.8M -115,552 -41%
DCM
37
DAFNA Capital Management
California
$5.21M +$1.95M +80,265 +94%
TAM
38
TFG Asset Management
Cayman Islands
$4.52M -$837K -34,513 -19%
Two Sigma Investments
39
Two Sigma Investments
New York
$4.37M +$3.03M +124,984 +920%
KCA
40
KVP Capital Advisors
California
$3.83M +$2.95M +121,524 New
Balyasny Asset Management
41
Balyasny Asset Management
Illinois
$3.78M +$2.28M +94,085 +367%
TD Asset Management
42
TD Asset Management
Ontario, Canada
$3.2M -$421K -17,342 -15%
BGM
43
Burkehill Global Management
New York
$3.15M – – –
Jane Street
44
Jane Street
New York
$2.73M +$2.1M +86,581 New
PHS
45
PFM Health Sciences
California
$2.5M -$3.45M -142,195 -64%
SC
46
Stempoint Capital
New York
$2.48M +$86.2K +3,553 +5%
Osaic Holdings
47
Osaic Holdings
Arizona
$2.45M +$1.88M +77,601 New
Susquehanna International Group
48
Susquehanna International Group
Pennsylvania
$2.41M +$1.86M +76,528 New
N
49
Nuveen
North Carolina
$2.38M +$1.3M +53,422 +241%
Bank of New York Mellon
50
Bank of New York Mellon
New York
$2.37M +$668K +27,527 +58%
1
2
3 4 5

MBX Hedge Fund Activity: Q4 2025 in Review

138 of the 8,223 institutional investors tracked by Wall St. Rank reported a position in MBX Biosciences (MBX) for Q4 2025, worth a combined $1.53B — up 83% from $836M a quarter earlier.

Buyers outnumbered sellers: 45 funds opened new MBX positions and 25 closed out — a net gain of 20 holders — while 53 added to existing stakes and 25 trimmed.

The largest buyer was Braidwell, opening a new position worth an estimated $24.7M. The largest seller was Wellington Management Group, cutting an estimated $35.8M.

  • 138 institutional investors held MBX Biosciences (MBX) as of Q4 2025, up from 118 in Q3 2025.
  • Funds reported $1.53B of MBX Biosciences stock for Q4 2025, up 83% quarter-over-quarter.
  • 45 funds opened new MBX Biosciences positions in Q4 2025 and 25 closed out, a net change of +20 holders.
  • The largest MBX Biosciences buyer in Q4 2025 was Braidwell, an estimated $24.7M added.
  • The largest MBX Biosciences seller in Q4 2025 was Wellington Management Group, an estimated $35.8M sold.

Based on aggregated 13F filings for Q4 2025.