UPSTREAM BIO INC (UPB) Institutional Shareholders
UPSTREAM BIO INC (UPB) is currently reported in institutional portfolios tracked by InsiderSet based on the latest available SEC Form 13F filings for the quarter ended June 30, 2026. The institutional investors covered on this page collectively reported approximately $349.91M in UPB holdings during the latest filing period.
Fmr Llc is currently the largest disclosed institutional shareholder of UPB tracked by InsiderSet, reporting ownership valued at approximately $56.49M in its June 30, 2026 SEC Form 13F filing. Based on current market prices and the latest disclosed share count, the position is now estimated to be worth approximately $43.59M, representing an estimated loss of -22.83% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 63% of the total disclosed UPB value among the investors covered in this analysis. Major shareholders include Fmr Llc, Orbimed Advisors Llc, Norges Bank, and several other long-term asset managers with concentrated positions in UPSTREAM BIO INC (UPB).
This page ranks the largest institutional UPB shareholders using publicly disclosed SEC Form 13F data, including reported values, estimated current holding values, portfolio allocation percentages, ownership concentration metrics, and historical holding changes across major hedge funds and investment firms.
Institutional Holders
145
Total Reported Value
$349.91M
Largest Holder
Fmr Llc
Largest Position
$56.49M
Insider Transactions (90d)
0
Latest Filing Quarter
Q2 2026
New Institutional Positions
120
Funds Exiting Positions
0
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Fmr Llc | 0.00% | 8,162,897 | $56,487,247 | $43,589,870 | -$12,897,377 | -22.83% | |
| Orbimed Advisors Llc | 0.75% | 5,693,589 | $39,399,636 | $30,403,765 | -$8,995,871 | -22.83% | |
| Norges Bank | 0.00% | 3,768,619 | $26,078,843 | $20,124,425 | -$5,954,418 | -22.83% | |
| Blackrock, Inc. | 0.00% | 3,753,358 | $25,973,237 | $20,042,932 | -$5,930,305 | -22.83% | |
| Decheng Capital Llc | 2.58% | 2,724,868 | $18,856,087 | $14,550,795 | -$4,305,292 | -22.83% | |
| Enavate Sciences Gp, Llc | 4.93% | 2,459,703 | $17,021,145 | $13,134,814 | -$3,886,331 | -22.83% | |
| Vanguard Capital Management Llc | 0.00% | 1,876,734 | $12,986,999 | $10,021,760 | -$2,965,239 | -22.83% | |
| Millennium Management Llc | 0.01% | 1,143,775 | $7,914,923 | $6,107,759 | -$1,807,165 | -22.83% | |
| D. E. Shaw & Co., Inc. | 0.00% | 1,036,044 | $7,169,425 | $5,532,475 | -$1,636,950 | -22.83% | |
| Jpmorgan Chase & Co | 0.00% | 1,012,044 | $7,013,464 | $5,404,315 | -$1,609,149 | -22.94% | |
| Qube Research & Technologies Ltd | 0.01% | 978,500 | $6,771,220 | $5,225,190 | -$1,546,030 | -22.83% | |
| Parkman Healthcare Partners Llc | 0.66% | 935,247 | $6,471,909 | $4,994,219 | -$1,477,690 | -22.83% | |
| Geode Capital Management, Llc | 0.00% | 931,261 | $6,445,888 | $4,972,934 | -$1,472,954 | -22.85% | |
| Seb Asset Management Ab | 0.02% | 878,473 | $6,079,022 | $4,691,046 | -$1,387,976 | -22.83% | |
| Woodline Partners Lp | 0.02% | 831,481 | $5,753,849 | $4,440,109 | -$1,313,740 | -22.83% | |
| State Street Corp | 0.00% | 766,323 | $5,302,955 | $4,092,165 | -$1,210,790 | -22.83% | |
| Vanguard Portfolio Management Llc | 0.00% | 712,667 | $4,931,656 | $3,805,642 | -$1,126,014 | -22.83% | |
| Y-Intercept (Hong Kong) Ltd | 0.09% | 693,555 | $4,799,401 | $3,703,584 | -$1,095,817 | -22.83% | |
| Bain Capital Life Sciences Investors, Llc | 0.25% | 600,949 | $4,158,567 | $3,209,068 | -$949,499 | -22.83% | |
| Aqr Capital Management Llc | 0.00% | 544,869 | $3,770,493 | $2,909,600 | -$860,893 | -22.83% | |
| Morgan Stanley | 0.00% | 524,632 | $3,630,453 | $2,801,535 | -$828,918 | -22.83% | |
| Bnp Paribas Financial Markets | 0.00% | 511,546 | $3,539,898 | $2,731,656 | -$808,242 | -22.83% | |
| Walleye Capital Llc | 0.02% | 498,490 | $3,449,551 | $2,661,937 | -$787,614 | -22.83% | |
| Trexquant Investment Lp | 0.02% | 466,430 | $3,227,696 | $2,490,736 | -$736,960 | -22.83% | |
| Point72 Asset Management, L.P. | 0.00% | 453,011 | $3,134,836 | $2,419,079 | -$715,757 | -22.83% | |
| Bank Of America Corp | 0.00% | 391,762 | $2,710,993 | $2,092,009 | -$618,984 | -22.83% | |
| Dimensional Fund Advisors Lp | 0.00% | 381,613 | $2,640,811 | $2,037,813 | -$602,998 | -22.83% | |
| Altshuler Shaham Ltd | 0.03% | 380,061 | $2,630,022 | $2,029,526 | -$600,496 | -22.83% | |
| Arrowstreet Capital, Limited Partnership | 0.00% | 357,756 | $2,475,672 | $1,910,417 | -$565,255 | -22.83% | |
| Samsara Biocapital, Llc | 0.20% | 353,717 | $2,447,722 | $1,888,849 | -$558,873 | -22.83% | |
| Propel Bio Management, Llc | 1.27% | 350,389 | $2,424,692 | $1,871,077 | -$553,615 | -22.83% | |
| Wellington Management Group Llp | 0.00% | 342,353 | $2,369,083 | $1,828,165 | -$540,918 | -22.83% | |
| Northern Trust Corp | 0.00% | 297,346 | $2,057,634 | $1,587,828 | -$469,806 | -22.83% | |
| Squarepoint Ops Llc | 0.00% | 290,904 | $2,013,056 | $1,553,427 | -$459,629 | -22.83% | |
| Voleon Capital Management Lp | 0.04% | 285,234 | $1,973,819 | $1,523,150 | -$450,669 | -22.83% | |
| Charles Schwab Investment Management Inc | 0.00% | 262,456 | $1,816,196 | $1,401,515 | -$414,681 | -22.83% | |
| Jacobs Levy Equity Management, Inc | 0.01% | 253,092 | $1,751,397 | $1,351,511 | -$399,886 | -22.83% | |
| Goldman Sachs Group Inc | 0.00% | 246,917 | $1,708,666 | $1,318,537 | -$390,129 | -22.83% | |
| Xtx Topco Ltd | 0.02% | 242,346 | $1,677,034 | $1,294,128 | -$382,906 | -22.83% | |
| Deutsche Bank Ag\ | 0.00% | 241,447 | $1,670,814 | $1,289,327 | -$381,487 | -22.83% | |
| Vanguard Fiduciary Trust Co | 0.00% | 239,616 | $1,658,143 | $1,279,549 | -$378,594 | -22.83% | |
| Ubs Group Ag | 0.00% | 234,714 | $1,624,221 | $1,253,373 | -$370,848 | -22.83% | |
| Schonfeld Strategic Advisors Llc | 0.01% | 225,760 | $1,562,258 | $1,205,558 | -$356,700 | -22.83% | |
| Jump Financial, Llc | 0.01% | 223,223 | $1,544,703 | $1,192,011 | -$352,692 | -22.83% | |
| Sphera Funds Management Ltd. | 0.22% | 219,700 | $1,520,324 | $1,173,198 | -$347,126 | -22.83% | |
| Acadian Asset Management Llc | 0.00% | 175,110 | $1,208,000 | $935,087 | -$272,913 | -22.59% | |
| Hrt Financial Lp | 0.00% | 170,590 | $1,180,000 | $910,951 | -$269,049 | -22.80% | |
| Boxer Capital Management, Llc | 0.08% | 150,000 | $1,038,000 | $801,000 | -$237,000 | -22.83% | |
| Renaissance Technologies LLC | Jim Simons | 0.00% | 131,300 | $908,596 | $701,142 | -$207,454 | -22.83% |
| Entrypoint Capital, Llc | 0.22% | 129,446 | $895,766 | $691,242 | -$204,524 | -22.83% |
Frequently asked questions about UPB
Who owns the most UPB stock?
The largest holders of UPB are typically major institutional investors such as asset managers and hedge funds reporting on Form 13F. The table above ranks tracked superinvestors by reported position size using the latest available filings for UPSTREAM BIO INC (UPB).
Is UPB widely held by superinvestors?
Many widely followed stocks like UPB appear across numerous superinvestor portfolios because of liquidity, index inclusion, and fundamentals. The holder count and table above show how broadly UPB is represented among the institutional managers we track.
What do “Current Estimated Value”, “Gain/loss Since Filing”, and “Estimated Portfolio Performance” mean?
Current Estimated Value is reported share quantity from the latest 13F times our most recent split-adjusted U.S. session close. Gain/loss Since Filing is that estimate minus the reported 13F dollar value; Estimated Portfolio Performance is that difference as a percent of the reported value. Green means the estimate is above the filing value; red means below (not purchase cost). If many filers share the same implied filing price per share, the performance % may match across rows. These are not official fund marks or live quotes.