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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
AC
101
AXQ Capital
New Jersey
$204K +$157K +6,463 New
SG Americas Securities
102
SG Americas Securities
New York
$150K +$116K +4,765 New
New York State Common Retirement Fund
103
New York State Common Retirement Fund
New York
$136K – – –
TRCT
104
Tower Research Capital (TRC)
New York
$108K +$52.1K +2,149 +170%
Rockefeller Capital Management
105
Rockefeller Capital Management
New York
$94.6K – – –
Russell Investments Group
106
Russell Investments Group
United Kingdom
$90.1K +$33.4K +1,375 +93%
Legal & General Group
107
Legal & General Group
United Kingdom
$80.1K +$29.4K +1,211 +91%
AIP
108
Ameritas Investment Partners
Nebraska
$72.9K +$27.5K +1,135 +96%
Mirae Asset Global Investments
109
Mirae Asset Global Investments
South Korea
$68.8K +$52.9K +2,182 New
Carson Wealth (CWM LLC)
110
Carson Wealth (CWM LLC)
Nebraska
$56K +$9.71K +400 +29%
California State Teachers Retirement System (CalSTRS)
111
California State Teachers Retirement System (CalSTRS)
California
$55.3K +$16.7K +689 +65%
SCM
112
Sterling Capital Management
North Carolina
$51.8K +$14.1K +583 +55%
Nisa Investment Advisors
113
Nisa Investment Advisors
Missouri
$50.2K – – –
Royal Bank of Canada
114
Royal Bank of Canada
Ontario, Canada
$49K +$13.9K +572 +60%
AB
115
Amalgamated Bank
New York
$28K +$12.4K +511 +133%
GFM
116
GF Fund Management
China
$27.8K +$21.4K +882 New
SO
117
STRS Ohio
Ohio
$22.1K – – –
US Bancorp
118
US Bancorp
Minnesota
$9.84K -$607 -25 -7%
GI
119
GAMMA Investing
California
$9.43K – – –
ACM
120
Aster Capital Management
United Arab Emirates
$8.36K +$6.43K +265 New
PNC Financial Services Group
121
PNC Financial Services Group
Pennsylvania
$6.18K -$1.36K -56 -22%
S
122
SignatureFD
Georgia
$5.65K – – –
Daiwa Securities Group
123
Daiwa Securities Group
Japan
$5K +$3.64K +150 New
PWA
124
Physician Wealth Advisors
Utah
$3.44K – – –
UBS AM
125
UBS AM
Illinois
$3.15K +$2.43K +100 New
3 4
5
6 7

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.