Upstream Bio, Inc. (UPB) Institutional Ownership

Institutions by Trading Activity

Ownership Statistics

53,568,254Shares Outstanding

9,646,417Shares held by institutions

$80,354,654Value of institutional holdings

93.61%Institutional ownership %

15.48%Shares Changed QoQ

127No. of institutional investors

Shares Owned by Institutions

Shares Purchased/Sold by Institutions

Ownership Summary

A total of 127 institutions have reported a stake in Upstream Bio, Inc. (NASDAQ:UPB) as of December 2025, according to recent 13F filings with the SEC.

These investors collectively held 93.6% of the company's total shares outstanding in December 2025, up from 83.5% in September 2025.
On a quarter-over-quarter basis, institutional holdings shifted by 15.48%, with a year-over-year an increase of 78.87% in the count of filers.
During the quarter, 83 institutions bought more Upstream Bio shares, 33 sold shares, and 11 of the 127 total investors held their position steady.
Collectively, institutional investors increased their stake in Upstream Bio to 50.15Mn shares as of December 2025, a change that is up by 6.72Mn shares quarter on quarter and up 8.07Mn shares year over year.
As of December 31, 2025, FMR LLC held Upstream Bio's largest shareholding position with over 7.52Mn shares, representing 14.03% of total outstanding shares.
Among the most significant buyers of Upstream Bio during December 2025 were NORGES BANK (2.88Mn), UBS Group AG (1.53Mn), JANUS HENDERSON GROUP PLC (1.53Mn), Pictet Asset Management Holding SA (773.15K), BlackRock, Inc. (740.80K).
Leading sellers of Upstream Bio stock in December 2025 included TCG Crossover Management, LLC (1.37Mn), Bain Capital Life Sciences Investors, LLC (1.11Mn), FMR LLC (568.21K), MARSHALL WACE, LLP (524.21K), WELLINGTON MANAGEMENT GROUP LLP (230.66K).
The top 10 institutional holders of Upstream Bio for the quarter ending December 2025 included FMR LLC (7.52Mn), ORBIMED ADVISORS LLC (5.69Mn), BlackRock, Inc. (3.34Mn), Decheng Capital LLC (3.14Mn), NORGES BANK (2.88Mn), Enavate Sciences GP, LLC (2.46Mn), VANGUARD GROUP INC (2.39Mn), UBS Group AG (1.81Mn), JANUS HENDERSON GROUP PLC (1.53Mn), Altshuler Shaham Ltd (1.34Mn).

127 Institutional Holders

9,646,417 Total Shares Held

Rows:

Download Data

Owner Name	Date	Shares Held	Change (QoQ)	Change (%)	Value (USD)
FMR LLC	31 Dec, 2025	7,518,202	-568,211	-7.03%	$204,119,193.00
ORBIMED ADVISORS LLC	31 Dec, 2025	5,693,589	0	0.00%	$154,580,941.00
BlackRock, Inc.	31 Dec, 2025	3,344,504	740,798	28.45%	$90,803,284.00
Decheng Capital LLC	31 Dec, 2025	3,143,078	-142,215	-4.33%	$85,334,568.00
NORGES BANK	31 Dec, 2025	2,882,647	2,882,647	0.00%	$78,263,866.00
Enavate Sciences GP, LLC	31 Dec, 2025	2,459,703	0	0.00%	$66,780,936.00
VANGUARD GROUP INC	31 Dec, 2025	2,388,439	-54,112	-2.22%	$64,846,119.00
UBS Group AG	31 Dec, 2025	1,806,243	1,533,972	563.40%	$49,039,498.00
JANUS HENDERSON GROUP PLC	31 Dec, 2025	1,527,958	1,527,958	0.00%	$41,422,941.00
Altshuler Shaham Ltd	31 Dec, 2025	1,341,540	-75,282	-5.31%	$36,422,811.00
Bain Capital Life Sciences Investors, LLC	31 Dec, 2025	1,329,544	-1,109,994	-45.50%	$36,097,120.00
Omega Fund Management, LLC	31 Dec, 2025	1,326,293	-30,000	-2.21%	$36,008,855.00
STATE STREET CORP	31 Dec, 2025	1,319,226	204,645	18.36%	$35,816,986.00
VR Adviser, LLC	31 Dec, 2025	1,169,298	0	0.00%	$31,746,441.00
WELLINGTON MANAGEMENT GROUP LLP	31 Dec, 2025	894,733	-230,662	-20.50%	$24,292,001.00
GEODE CAPITAL MANAGEMENT, LLC	31 Dec, 2025	851,908	34,799	4.26%	$23,134,004.00
Pictet Asset Management Holding SA	31 Dec, 2025	773,148	773,148	0.00%	$20,990,968.00
Woodline Partners LP	31 Dec, 2025	760,252	158,000	26.23%	$20,640,842.00
Integral Health Asset Management, LLC	31 Dec, 2025	750,000	175,000	30.43%	$20,362,500.00
TCG Crossover Management, LLC	31 Dec, 2025	743,886	-1,373,217	-64.86%	$20,196,505.00

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