Upstream Bio Inc
UPB
133 hedge funds and large institutions have $1.39B invested in Upstream Bio Inc in 2025 Q4 according to their latest regulatory filings, with 46 funds opening new positions, 42 increasing their positions, 33 reducing their positions, and 8 closing their positions.
475% more first-time investments, than exits
New positions opened: 46 | Existing positions closed: 8
73% more call options, than puts
Call options by funds: $1.45M | Put options by funds: $842K
66% more capital invested
Capital invested by funds: $836M → $1.39B (+$553M)
40% more funds holding
Funds holding: 95 → 133 (+38)
27% more repeat investments, than reductions
Existing positions increased: 42 | Existing positions reduced: 33
20% more funds holding in top 10
Funds holding in top 10: 5 → 6 (+1)
12.23% more ownership
Funds ownership: 82.48% → 94.7% (+12%)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
UBS Group
Zurich,
Switzerland
|
+$38.2M |
| 2 |
Janus Henderson Group
London,
United Kingdom
|
+$38M |
| 3 |
Pictet Asset Management
Carouge,
Switzerland
|
+$19.2M |
| 4 |
BlackRock
New York
|
+$18.4M |
| 5 |
VPC
Vestal Point Capital
New York
|
+$17.9M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
TCM
TCG Crossover Management
Palo Alto,
California
|
-$34.2M |
| 2 |
BCLSI
Bain Capital Life Sciences Investors
Boston,
Massachusetts
|
-$27.6M |
| 3 |
Fidelity Investments
Boston,
Massachusetts
|
-$14.1M |
| 4 |
Marshall Wace
London,
United Kingdom
|
-$13M |
| 5 |
Wellington Management Group
Boston,
Massachusetts
|
-$5.74M |
UPB Hedge Fund Activity: Q4 2025 in Review
133 of the 8,225 institutional investors tracked by Wall St. Rank reported a position in Upstream Bio Inc (UPB) for Q4 2025, worth a combined $1.39B — up 66% from $836M a quarter earlier.
Buyers outnumbered sellers: 46 funds opened new UPB positions and 8 closed out — a net gain of 38 holders — while 42 added to existing stakes and 33 trimmed.
The largest buyer was UBS Group, adding an estimated $38.2M. The largest seller was TCG Crossover Management, cutting an estimated $34.2M.
- 133 institutional investors held Upstream Bio Inc (UPB) as of Q4 2025, up from 95 in Q3 2025.
- Funds reported $1.39B of Upstream Bio Inc stock for Q4 2025, up 66% quarter-over-quarter.
- 46 funds opened new Upstream Bio Inc positions in Q4 2025 and 8 closed out, a net change of +38 holders.
- The largest Upstream Bio Inc buyer in Q4 2025 was UBS Group, an estimated $38.2M added.
- The largest Upstream Bio Inc seller in Q4 2025 was TCG Crossover Management, an estimated $34.2M sold.
Based on aggregated 13F filings for Q4 2025.