UPB Upstream Bio, Inc.

NASDAQ
$5.36

Upstream Bio, Inc. (UPB) Hedge Fund Activity

This view isolates hedge funds from the broader institutional ownership shown on the Institutional tab. A pension fund tracking an index may have no view on a stock; when a hedge fund builds or exits a position, that decision can carry information. This page measures those changes. Positions as of June 30, 2026.

Based on quarterly 13F long-equity filings. Changes compare reported quarter-end positions; filings can be reported up to 45 days later and do not represent a fund's complete exposure.

Hedge fund breadth
+40.74
19 buyers / 8 sellers
STRONG BUYING
Funds compared
29
funds with comparable UPB positions
23 current holders · 21 prior-quarter holders
Net share change
+2.01M
+3.23M added, -1.22M cut
Position activity
8 new 11 increased 2 reduced 6 exited

Most significant moves

Ranked by conviction, not size — how much of the fund's own book the position represents, how far it moved, and what kind of fund made it.

Fund Action Shares changed Change Est. value Portfolio wt. Score
Alyeska Investment Group, L.P. Sold Out -298.3K -100.0% $2.1M 0.0% 58
TWO SIGMA INVESTMENTS, LP Quant New +42.3K — $292.9K 0.0% 57
Nantahala Capital Management Event Long/Short Sold Out -400.0K -100.0% $2.8M 0.0% 56
MARSHALL WACE, LLP Long/Short Sold Out -66.8K -100.0% $462.0K 0.0% 56
Point72 Asset Management, L.P. Increased +274.8K +154.3% $1.9M 0.0% 55
Tudor Investment Corporation Macro Sold Out -26.4K -100.0% $182.8K 0.0% 53
Walleye Capital Long/Short Quant New +498.5K — $3.4M 0.0% 53
ADAR1 Capital Management Long/Short Growth Sold Out -35.0K -100.0% $242.2K 0.0% 53
Voleon Capital Management Quant New +285.2K — $2.0M 0.0% 53
Quadrature Capital Quant New +18.0K — $124.5K 0.0% 52

Most significant buyers

By move score, not size.

  • TWO SIGMA INVESTMENTS, LP New · +42.3K
  • Point72 Asset Management, L.P. Increased · +274.8K
  • Walleye Capital New · +498.5K
  • Voleon Capital Management New · +285.2K
  • Quadrature Capital New · +18.0K

Most significant sellers

By move score, not size.

  • Alyeska Investment Group, L.P. Sold Out · -298.3K
  • Nantahala Capital Management Sold Out · -400.0K
  • MARSHALL WACE, LLP Sold Out · -66.8K
  • Tudor Investment Corporation Sold Out · -26.4K
  • ADAR1 Capital Management Sold Out · -35.0K

Hedge fund positions

Fund Tier Shares Previous Change Change % Portfolio wt. Action Score
Alyeska Investment Group, L.P. 2 0 298.3K -298.3K -100.0% 0.0% Sold Out 58
TWO SIGMA INVESTMENTS, LP 2 42.3K 0 +42.3K — 0.0% New 57
Nantahala Capital Management 3 0 400.0K -400.0K -100.0% 0.0% Sold Out 56
MARSHALL WACE, LLP 2 0 66.8K -66.8K -100.0% 0.0% Sold Out 56
Point72 Asset Management, L.P. 1 453.0K 178.2K +274.8K +154.3% 0.0% Increased 55
Tudor Investment Corporation 2 0 26.4K -26.4K -100.0% 0.0% Sold Out 53
Walleye Capital 3 498.5K 0 +498.5K — 0.0% New 53
ADAR1 Capital Management 3 0 35.0K -35.0K -100.0% 0.0% Sold Out 53
Voleon Capital Management 3 285.2K 0 +285.2K — 0.0% New 53
Quadrature Capital 3 18.0K 0 +18.0K — 0.0% New 52
RENAISSANCE TECHNOLOGIES LLC 1 131.3K 62.1K +69.2K +111.4% 0.0% Increased 52
Squarepoint Ops LLC 2 290.9K 44.6K +246.3K +551.9% 0.0% Increased 51
Brevan Howard Capital Management 3 50.4K 0 +50.4K — 0.0% New 49
Graham Capital Management 3 22.5K 0 +22.5K — 0.0% New 49
Winton Group 4 19.8K 0 +19.8K — 0.0% New 48
Aquatic Capital Management 4 0 31.5K -31.5K -100.0% 0.0% Sold Out 48
Engineers Gate 4 12.5K 0 +12.5K — 0.0% New 48
Trexquant Investment 3 466.4K 176.7K +289.8K +164.0% 0.0% Increased 47
AQR Capital Management 3 544.9K 72.2K +472.7K +655.0% 0.0% Increased 47
Man Group 3 73.8K 21.2K +52.7K +249.0% 0.0% Increased 46
Qube Research & Technologies Ltd 2 978.5K 619.3K +359.2K +58.0% 0.0% Increased 41
Quantbot Technologies 4 28.2K 663 +27.5K +4150.1% 0.0% Increased 39
D. E. Shaw & Co., Inc. 1 1.0M 820.5K +215.6K +26.3% 0.0% Increased 35
ExodusPoint Capital Management 3 41.0K 91.4K -50.4K -55.1% 0.0% Reduced 35
MILLENNIUM MANAGEMENT LLC 2 1.1M 937.3K +206.5K +22.0% 0.0% Increased 34
Schonfeld Strategic Advisors 3 225.8K 161.3K +64.4K +39.9% 0.0% Increased 30
Y-Intercept 4 693.6K 1.0M -307.1K -30.7% 0.1% Reduced 28
OrbiMed Advisors 2 5.7M 5.7M 0 +0.0% 0.7% Unchanged 27
Woodline Partners LP 2 831.5K 831.5K 0 +0.0% 0.0% Unchanged 18

Every fund above opens. Subscribers can see any manager's whole portfolio — every position, its weight, and what they bought, trimmed and exited last quarter.

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Hedge funds are identified from their 13F filings, which are due 45 days after quarter end and cover long U.S.-listed equity positions only. A fund's short book never appears, so a reduced position can mean a changed view or a changed hedge — the filing doesn't say which.