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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
FLSM
1
Frazier Life Sciences Management
California
$210M – – –
O
2
OrbiMed
New York
$124M -$1.64M -67,684 -2%
NMC
3
NEA Management Company
Maryland
$114M – – –
Wellington Management Group
4
Wellington Management Group
Massachusetts
$106M -$35.8M -1,473,375 -31%
DTC
5
Deep Track Capital
Connecticut
$102M +$2.42M +99,790 +3%
BlackRock
6
BlackRock
New York
$92.1M +$23.3M +962,295 +49%
NA
7
NVP Associates
California
$67.4M – – –
EC
8
EcoR1 Capital
California
$67M – – –
Vanguard Group
9
Vanguard Group
Pennsylvania
$57.3M +$3.41M +140,449 +8%
DCM
10
Driehaus Capital Management
Illinois
$44.4M -$3.19M -131,480 -9%
CAM
11
Cormorant Asset Management
Massachusetts
$35.3M -$2.55M -105,000 -9%
B
12
Braidwell
Connecticut
$32.1M +$24.7M +1,018,600 New
WP
13
Woodline Partners
California
$31.5M -$4.88M -201,087 -17%
KCM
14
Kynam Capital Management
New Jersey
$29.5M -$25.8M -1,065,201 -53%
EAM
15
Eventide Asset Management
Massachusetts
$28.1M +$21.6M +890,000 New
PHP
16
Parkman Healthcare Partners
Connecticut
$27.9M +$2.73M +112,335 +15%
T. Rowe Price Associates
17
T. Rowe Price Associates
Maryland
$26.5M -$2.77M -114,220 -12%
Citadel Advisors
18
Citadel Advisors
Florida
$25.5M -$4.52M -186,226 -19%
Point72 Asset Management
19
Point72 Asset Management
Connecticut
$21.5M +$1.28M +52,942 +8%
State Street
20
State Street
Massachusetts
$21.2M +$8.58M +353,466 +111%
D.E. Shaw & Co
21
D.E. Shaw & Co
New York
$21.2M +$16.3M +671,838 New
TCM
22
TCG Crossover Management
California
$20.5M – – –
Geode Capital Management
23
Geode Capital Management
Massachusetts
$20.5M +$4.26M +175,459 +37%
Millennium Management
24
Millennium Management
New York
$14.6M -$4.69M -193,367 -30%
SCM
25
Soleus Capital Management
Connecticut
$12.9M +$3.25M +133,900 +49%
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.