Upstream Bio, Inc. (UPB) — Institutional Holders, Q2 2026

150 institutional investment managers reported a UPB position on SEC Form 13F-HR for the quarter ended June 30, 2026, with a combined reported value of $349.9M. Every filer is listed below, ranked by position value, 100 per page; this page shows ranks 1 to 100. Put and call option positions are excluded, and a firm filing several lots or share classes is shown once with its total.

← UPB stock profile

UPB in Q2 2026: what funds did

Funds that filed a 13F for both Q1 2026 and Q2 2026, by what they did with the common stock. Share counts are adjusted for any split between the two quarters; dollar figures are the change in shares at this quarter’s price.

New positions

Added to

Trimmed

Sold out

Biggest buyers

JPMORGAN CHASEAdded · +549,043 sh+$3.8M
Walleye CapitalNew · +498,490 sh+$3.4M
AQR CAPITAL MANAGEMENTAdded · +472,698 sh+$3.3M
BNP PARIBAS FINANCIAL MARKETSAdded · +385,546 sh+$2.7M
BlackRockAdded · +382,669 sh+$2.6M

Biggest sellers

FEDERATED HERMESSold out · -979,758 sh-$6.8M
Pictet Asset Management Holding SASold out · -733,431 sh-$5.1M
HSBC PLCTrimmed · -629,533 sh-$4.4M
Nantahala Capital ManagementSold out · -400,000 sh-$2.8M
Samsara BioCapitalTrimmed · -382,330 sh-$2.6M

UPB 13F holders ranked 1–100 of 150

Institutional investors reporting a position in Upstream Bio, Inc. on SEC Form 13F-HR for Q2 2026, ranked by reported value.
#	Institution	Shares	Value	% of portfolio	QoQShares vs Q1 2026
1	FMR#1 · 8,162,897 sh	8,162,897	$56.5M	<0.01%	+0.8%
2	ORBIMED ADVISORS#2 · 5,693,589 sh	5,693,589	$39.4M	0.73%	0.0%
3	NORGES BANK#3 · 3,768,619 sh	3,768,619	$26.1M	<0.01%	—
4	BlackRock#4 · 3,753,358 sh	3,753,358	$26.0M	<0.01%	+11.4%
5	Decheng Capital#5 · 2,724,868 sh	2,724,868	$18.9M	2.58%	0.0%
6	Enavate Sciences GP#6 · 2,459,703 sh	2,459,703	$17.0M	4.93%	0.0%
7	VANGUARD CAPITAL MANAGEMENT#7 · 1,876,734 sh	1,876,734	$13.0M	<0.01%	+0.2%
8	MILLENNIUM MANAGEMENT#8 · 1,143,775 sh	1,143,775	$7.9M	<0.01%	+22.0%
9	D. E. Shaw#9 · 1,036,044 sh	1,036,044	$7.2M	<0.01%	+26.3%
10	JPMORGAN CHASE#10 · 1,012,044 sh	1,012,044	$7.0M	<0.01%	+118.6%
11	Qube Research & Technologies Ltd#11 · 978,500 sh	978,500	$6.8M	<0.01%	+58.0%
12	Parkman Healthcare Partners#12 · 935,247 sh	935,247	$6.5M	0.66%	+18.9%
13	GEODE CAPITAL MANAGEMENT#13 · 931,261 sh	931,261	$6.4M	<0.01%	-2.0%
14	SEB Asset Management AB#14 · 878,473 sh	878,473	$6.1M	0.02%	0.0%
15	Woodline Partners#15 · 831,481 sh	831,481	$5.8M	0.02%	0.0%
16	STATE STREET#16 · 766,323 sh	766,323	$5.3M	<0.01%	+8.6%
17	VANGUARD PORTFOLIO MANAGEMENT#17 · 712,667 sh	712,667	$4.9M	<0.01%	-2.1%
18	Y-Intercept (Hong Kong) Ltd#18 · 693,555 sh	693,555	$4.8M	—	-30.7%
19	Bain Capital Life Sciences Investors#19 · 600,949 sh	600,949	$4.2M	0.25%	-30.7%
20	AQR CAPITAL MANAGEMENT#20 · 544,869 sh	544,869	$3.8M	<0.01%	+655.0%
21	MORGAN STANLEY#21 · 524,632 sh	524,632	$3.6M	<0.01%	-5.1%
22	BNP PARIBAS FINANCIAL MARKETS#22 · 511,546 sh	511,546	$3.5M	<0.01%	+306.0%
23	Walleye Capital#23 · 498,490 sh	498,490	$3.4M	0.01%	New
24	Trexquant Investment#24 · 466,430 sh	466,430	$3.2M	0.02%	+164.0%
25	Point72 Asset Management, L.P.#25 · 453,011 sh	453,011	$3.1M	<0.01%	+154.3%
26	BANK OF AMERICA#26 · 391,762 sh	391,762	$2.7M	<0.01%	+708.4%
27	DIMENSIONAL FUND ADVISORS#27 · 381,613 sh	381,613	$2.6M	<0.01%	+377.0%
28	Altshuler Shaham Ltd#28 · 380,061 sh	380,061	$2.6M	0.03%	0.0%
29	ARROWSTREET CAPITAL, LIMITED PARTNERSHIP#29 · 357,756 sh	357,756	$2.5M	<0.01%	+93.3%
30	Samsara BioCapital#30 · 353,717 sh	353,717	$2.4M	0.20%	-51.9%
31	Propel Bio Management#31 · 350,389 sh	350,389	$2.4M	1.27%	+2.5%
32	WELLINGTON MANAGEMENT GROUP LLP#32 · 342,353 sh	342,353	$2.4M	<0.01%	0.0%
33	NORTHERN#33 · 297,346 sh	297,346	$2.1M	<0.01%	+13.9%
34	Squarepoint Ops#34 · 290,904 sh	290,904	$2.0M	<0.01%	+551.9%
35	Voleon Capital Management#35 · 285,234 sh	285,234	$2.0M	0.04%	New
36	CHARLES SCHWAB INVESTMENT MANAGEMENT#36 · 262,456 sh	262,456	$1.8M	<0.01%	+1.8%
37	JACOBS LEVY EQUITY MANAGEMENT#37 · 253,092 sh	253,092	$1.8M	<0.01%	New
38	GOLDMAN SACHS GROUP#38 · 246,917 sh	246,917	$1.7M	<0.01%	-22.0%
39	XTX Topco Ltd#39 · 242,346 sh	242,346	$1.7M	0.02%	+15.8%
40	DEUTSCHE BANK AG\#40 · 241,447 sh	241,447	$1.7M	<0.01%	+33.5%
41	VANGUARD FIDUCIARY#41 · 239,616 sh	239,616	$1.7M	<0.01%	+6.9%
42	UBS Group AG#42 · 234,714 sh	234,714	$1.6M	<0.01%	+1.5%
43	Schonfeld Strategic Advisors#43 · 225,760 sh	225,760	$1.6M	<0.01%	+39.9%
44	Jump Financial#44 · 223,223 sh	223,223	$1.5M	0.01%	-30.1%
45	SPHERA FUNDS MANAGEMENT LTD.#45 · 219,700 sh	219,700	$1.5M	0.20%	-38.6%
46	ACADIAN ASSET MANAGEMENT#46 · 175,110 sh	175,110	$1.2M	<0.01%	New
47	HRT FINANCIAL#47 · 170,590 sh	170,590	$1.2M	<0.01%	New
48	Boxer Capital Management#48 · 150,000 sh	150,000	$1.0M	0.08%	0.0%
49	RENAISSANCE TECHNOLOGIES#49 · 131,300 sh	131,300	$908.6K	<0.01%	+111.4%
50	EntryPoint Capital#50 · 129,446 sh	129,446	$895.8K	0.22%	+76.0%
51	ALGERT GLOBAL#51 · 118,630 sh	118,630	$820.9K	<0.01%	New
52	Bank of New York Mellon#52 · 85,747 sh	85,747	$593.4K	<0.01%	+5.4%
53	Nuveen#53 · 84,770 sh	84,770	$586.6K	<0.01%	+12.2%
54	AMERICAN CENTURY COMPANIES#54 · 78,194 sh	78,194	$541.1K	<0.01%	-10.8%
55	Man Group plc#55 · 73,823 sh	73,823	$510.9K	<0.01%	+249.0%
56	GSA CAPITAL PARTNERS LLP#56 · 69,348 sh	69,348	$480.0K	0.03%	+76.8%
57	ALLIANCEBERNSTEIN L.P.#57 · 51,680 sh	51,680	$465.1K	<0.01%	+66.7%
58	Simplify Asset Management#58 · 62,113 sh	62,113	$429.8K	<0.01%	-20.2%
59	ALPS ADVISORS#59 · 55,228 sh	55,228	$382.2K	<0.01%	+25.5%
60	Quantinno Capital Management#60 · 54,838 sh	54,838	$379.5K	<0.01%	+11.0%
61	Virtus Investment Advisers#61 · 53,638 sh	53,638	$371.2K	0.09%	+433.9%
62	Invesco Ltd.#62 · 53,397 sh	53,397	$369.5K	0.00%	+31.8%
63	Brevan Howard Capital Management#63 · 50,369 sh	50,369	$348.6K	<0.01%	New
64	Swiss National Bank#64 · 48,100 sh	48,100	$332.9K	<0.01%	0.0%
65	Russell Investments Group, Ltd.#65 · 47,543 sh	47,543	$329.0K	<0.01%	+1203.6%
66	Allspring Global Investments#66 · 43,182 sh	43,182	$298.8K	<0.01%	New
67	RHUMBLINE ADVISERS#67 · 42,384 sh	42,384	$293.3K	<0.01%	+2.9%
68	TWO SIGMA INVESTMENTS#68 · 42,325 sh	42,325	$292.9K	<0.01%	New
69	ExodusPoint Capital Management#69 · 41,045 sh	41,045	$284.0K	<0.01%	-55.1%
70	CITIGROUP#70 · 40,339 sh	40,339	$279.1K	<0.01%	+698.0%
71	Stonepine Capital Management#71 · 33,432 sh	33,432	$231.3K	0.11%	-4.5%
72	Mariner#72 · 33,141 sh	33,141	$229.3K	<0.01%	+21.3%
73	WELLS FARGO & COMPANY#73 · 29,497 sh	29,497	$204.1K	0.00%	+60.3%
74	BARCLAYS PLC#74 · 29,208 sh	29,208	$202.1K	0.00%	+18.2%
75	Creative Planning#75 · 28,483 sh	28,483	$197.1K	<0.01%	+162.5%
76	PRICE T ROWE ASSOCIATES#76 · 28,058 sh	28,058	$195.0K	0.00%	+6.1%
77	Quantbot Technologies#77 · 28,178 sh	28,178	$195.0K	<0.01%	+4150.1%
78	AXQ CAPITAL#78 · 27,068 sh	27,068	$187.3K	0.02%	-1.6%
79	nVerses Capital#79 · 24,029 sh	24,029	$166.3K	0.26%	New
80	DnB Asset Management AS#80 · 23,600 sh	23,600	$163.3K	<0.01%	+0.4%
81	VANGUARD ASSET MANAGEMENT, Ltd#81 · 22,724 sh	22,724	$157.3K	<0.01%	+145.7%
82	Graham Capital Management, L.P.#82 · 22,508 sh	22,508	$155.8K	<0.01%	New
83	LOS ANGELES CAPITAL MANAGEMENT#83 · 22,385 sh	22,385	$154.9K	<0.01%	New
84	Verdad Advisers#84 · 21,810 sh	21,810	$150.9K	0.14%	New
85	MetLife Investment Management#85 · 20,852 sh	20,852	$144.3K	<0.01%	+7.6%
86	SG Americas Securities#86 · 20,338 sh	20,338	$141.0K	<0.01%	New
87	SEI INVESTMENTS#87 · 20,026 sh	20,026	$138.6K	<0.01%	New
88	WINTON GROUP Ltd#88 · 19,800 sh	19,800	$137.0K	<0.01%	New
89	IEQ CAPITAL#89 · 19,535 sh	19,535	$135.2K	<0.01%	New
90	DIADEMA PARTNERS#90 · 19,093 sh	19,093	$132.1K	0.02%	-11.6%
91	Shay Capital#91 · 18,000 sh	18,000	$124.6K	<0.01%	+80.0%
92	Quadrature Capital Ltd#92 · 17,988 sh	17,988	$124.5K	<0.01%	New
93	Entropy Technologies#93 · 17,542 sh	17,542	$121.4K	<0.01%	-24.8%
94	STATE OF WISCONSIN INVESTMENT BOARD#94 · 17,065 sh	17,065	$118.1K	<0.01%	-59.0%
95	MIRAE ASSET GLOBAL ETFS Ltd.#95 · 16,217 sh	16,217	$112.2K	<0.01%	+3.9%
96	MANUFACTURERS LIFE INSURANCE COMPANY, THE#96 · 15,735 sh	15,735	$108.9K	<0.01%	+2.6%
97	JANE STREET GROUP#97 · 15,594 sh	15,594	$107.9K	0.00%	New
98	MERCER GLOBAL ADVISORS#98 · 13,352 sh	13,352	$92.4K	<0.01%	New
99	Vanguard Global Advisers#99 · 13,059 sh	13,059	$90.4K	0.00%	0.0%
100	Legal & General Group Plc#100 · 12,561 sh	12,561	$86.9K	0.00%	+30.7%

Funds that sold out of UPB in Q2 2026 (27)

Held UPB at the end of Q1 2026 and filed a Q2 2026 13F without it. Not in the list above, because they no longer hold it. Largest prior position first.

Institutions that held UPB in Q1 2026 and reported no position in Q2 2026.
Institution	Shares sold	Value in Q1 2026
FEDERATED HERMES979,758 sh	979,758	$8.8M
Pictet Asset Management Holding SA733,431 sh	733,431	$6.6M
Nantahala Capital Management400,000 sh	400,000	$3.6M
Alyeska Investment Group, L.P.298,329 sh	298,329	$2.7M
Prosight Management241,123 sh	241,123	$2.2M
TCG Crossover Management181,063 sh	181,063	$1.6M
MARSHALL WACE, LLP66,770 sh	66,770	$600.9K
ADAR1 Capital Management35,000 sh	35,000	$315.0K
Aquatic Capital Management31,484 sh	31,484	$283.4K
Bleakley Financial Group28,864 sh	28,864	$259.8K
TUDOR INVESTMENT ET AL26,412 sh	26,412	$237.7K
MARTINGALE ASSET MANAGEMENT L P26,223 sh	26,223	$236.0K
VICTORY CAPITAL MANAGEMENT25,866 sh	25,866	$232.8K
SUSQUEHANNA INTERNATIONAL GROUP, LLP15,961 sh	15,961	$143.6K
FRANKLIN RESOURCES14,589 sh	14,589	$131.3K
Corient Private Wealth12,157 sh	12,157	$109.4K
Larson Financial Group1,107 sh	1,107	$10.0K
Versant Capital Management762 sh	762	$6.9K
MAI Capital Management171 sh	171	$1.5K
Torren Management162 sh	162	$1.5K
NATIXIS120 sh	120	$1.1K
Wealth Preservation Advisors86 sh	86	$774.00
SIGNATUREFD66 sh	66	$594.00
Ameritas Advisory Services31 sh	31	$279.00
Caitong International Asset Management , Ltd23 sh	23	$207.00
Root Financial Partners20 sh	20	$180.00
Parallel Advisors2 sh	2	$18.00

Source: Form 13F-HR filings on SEC EDGAR, Q2 2026. Values are as reported by each manager at quarter end. “% of portfolio” is the position’s share of the manager’s total reported 13F value for the same quarter. “New” means the manager filed a 13F for Q1 2026 without this position; a dash means no comparison is available. Where a manager’s own filing is internally inconsistent its value is withheld and it is listed last. 13F data shows reported holdings, not recommendations.