MBX Biosciences
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.
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
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
B
Braidwell
Stamford,
Connecticut
|
+$24.7M |
| 2 |
BlackRock
New York
|
+$23.3M |
| 3 |
EAM
Eventide Asset Management
Boston,
Massachusetts
|
+$21.6M |
| 4 |
D.E. Shaw & Co
New York
|
+$16.3M |
| 5 |
State Street
Boston,
Massachusetts
|
+$8.58M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Wellington Management Group
Boston,
Massachusetts
|
-$35.8M |
| 2 |
KCM
Kynam Capital Management
Princeton,
New Jersey
|
-$25.8M |
| 3 |
Franklin Resources
San Mateo,
California
|
-$22.9M |
| 4 |
WP
Woodline Partners
San Francisco,
California
|
-$4.88M |
| 5 |
BBA
Baker Bros. Advisors
New York
|
-$4.86M |
MBX Hedge Fund Activity: Q4 2025 in Review
138 of the 8,270 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.