Upstream Bio Inc
UPB
140 hedge funds and large institutions have $404M invested in Upstream Bio Inc in 2026 Q1 according to their latest regulatory filings, with 47 funds opening new positions, 47 increasing their positions, 35 reducing their positions, and 37 closing their positions.
34% more repeat investments, than reductions
Existing positions increased: 47 | Existing positions reduced: 35
27% more first-time investments, than exits
New positions opened: 47 | Existing positions closed: 37
11% more call options, than puts
Call options by funds: $972K | Put options by funds: $872K
5% more funds holding
Funds holding: 133 → 140 (+7)
12.22% less ownership
Funds ownership: 94.7% → 82.48% (-12%)
67% less funds holding in top 10
Funds holding in top 10: 6 → 2 (-4)
71% less capital invested
Capital invested by funds: $1.39B → $404M (-$985M)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Federated Hermes
Pittsburgh,
Pennsylvania
|
+$17.6M |
| 2 |
YIH
Y-Intercept (HK)
Hong Kong
|
+$17.2M |
| 3 |
D.E. Shaw & Co
New York
|
+$14.3M |
| 4 |
HSBC Holdings
London,
United Kingdom
|
+$11.5M |
| 5 |
Qube Research & Technologies (QRT)
London,
United Kingdom
|
+$11.1M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Janus Henderson Group
London,
United Kingdom
|
-$41.4M |
| 2 |
OFM
Omega Fund Management
Boston,
Massachusetts
|
-$36M |
| 3 |
VA
VR Adviser
New York
|
-$31.7M |
| 4 |
UBS Group
Zurich,
Switzerland
|
-$28.3M |
| 5 |
IHAM
Integral Health Asset Management
New York
|
-$20.4M |
UPB Hedge Fund Activity: Q1 2026 in Review
140 of the 8,126 institutional investors tracked by Wall St. Rank reported a position in Upstream Bio Inc (UPB) for Q1 2026, worth a combined $404M — down 71% from $1.39B a quarter earlier.
Buyers outnumbered sellers: 47 funds opened new UPB positions and 37 closed out — a net gain of 10 holders — while 47 added to existing stakes and 35 trimmed.
The largest buyer was Federated Hermes, adding an estimated $17.6M. The largest seller was Janus Henderson Group, exiting entirely with an estimated $41.4M sold.
- 140 institutional investors held Upstream Bio Inc (UPB) as of Q1 2026, up from 133 in Q4 2025.
- Funds reported $404M of Upstream Bio Inc stock for Q1 2026, down 71% quarter-over-quarter.
- 47 funds opened new Upstream Bio Inc positions in Q1 2026 and 37 closed out, a net change of +10 holders.
- The largest Upstream Bio Inc buyer in Q1 2026 was Federated Hermes, an estimated $17.6M added.
- The largest Upstream Bio Inc seller in Q1 2026 was Janus Henderson Group, an estimated $41.4M sold.
Based on aggregated 13F filings for Q1 2026.