Significant Ownership of EcoR1 Capital, LLC

Large-stake snapshot 1 signal
Large-stake filing summary
  • Recent SEC Schedule 13D/G filings for EcoR1 Capital, LLC focus on large-stake beneficial ownership disclosures and amendments.
  • Use this view to spot new large holders, amended positions, and activist-style ownership evidence.
Manager Names, identifiers, and filing context for this profile. 2 identity fields
Manager signature
/s/ Oleg Nodelman - Manager
Manager location
San Francisco, CA

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Significant Ownership of EcoR1 Capital, LLC

Sym Company Class Ownership Holdings Value Net Change Nb Shares Change % Reporting Name Report Period
ZYME Zymeworks Inc. Common Stock 31% $420,817,508 22,970,388 0% EcoR1 Capital, LLC 16 Nov 2025
ITOS iTeos Therapeutics, Inc. Common Stock 28% $78,563,988 +$36,448,488 10,688,978 +87% EcoR1 Capital, LLC 15 May 2025
ATRA Atara Biotherapeutics, Inc. Common Stock 17% 1,552,000 EcoR1 Capital, LLC 07 May 2026
GLPG Galapagos NV Ordinary Shares, no par value 13% $243,919,471 +$25,507,847 8,714,522 +12% EcoR1 Capital, LLC 24 Jul 2025
NGNE Neurogene Inc. Common Stock 9.9% $25,005,492 1,442,902 EcoR1 Capital, LLC 30 Sep 2025
ATRA Atara Biotherapeutics, Inc. Common Stock 9.9% $10,258,030 715,853 EcoR1 Capital, LLC 30 Sep 2025
IBIO iBio, Inc. Common Stock 9.9% $2,673,600 2,228,000 EcoR1 Capital, LLC 10 Dec 2025
Eloxx Pharmaceuticals, Inc. Comon Stock 9.9% 403,586 EcoR1 Capital, LLC 09 Jun 2026
Aktis Oncology, Inc. Common Stock 9.1% 4,862,335 Oleg Nodelman 12 Jan 2026
FULC Fulcrum Therapeutics, Inc. Common Stock 9% $41,760,000 6,000,000 EcoR1 Capital, LLC 17 Jun 2026
MREO Mereo BioPharma Group plc Ordinary Shares 8.4% $22,058,611 -$2,526,389 66,844,275 -10% EcoR1 Capital, LLC 31 Mar 2026
ALVR Allovir, Inc. Common Stock 8.1% $3,886,623 408,688 EcoR1 Capital, LLC 31 Dec 2024
ETON Eton Pharmaceuticals, Inc. Common Stock 7.7% $28,407,583 1,981,003 EcoR1 Capital, LLC 31 Dec 2024
ORIC ORIC Pharmaceuticals, Inc. Common Stock 6.9% $73,336,464 6,728,116 EcoR1 Capital, LLC 29 Jul 2025
KURA Kura Oncology, Inc. Common Stock 4.8% $23,520,000 4,200,000 EcoR1 Capital, LLC 30 Jun 2025
IMNM Immunome Inc. Common Stock 4.7% $34,756,616 4,079,415 EcoR1 Capital, LLC 31 Mar 2025
IBIO iBio, Inc. Common Stock 4.6% 1,583,000 EcoR1 Capital, LLC 31 Mar 2026
ADAP Adaptimmune Therapeutics PLC Ordinary Shares 4.2% $6,600,000 66,000,000 EcoR1 Capital, LLC 15 Aug 2025
AVIR Atea Pharmaceuticals, Inc. Common Stock 4% $9,857,876 3,341,653 EcoR1 Capital, LLC 31 Dec 2024
HOOK HOOKIPA Pharma Inc. Common Stock 4% $326,643 388,861 EcoR1 Capital, LLC 31 Dec 2024
ALGS Aligos Therapeutics, Inc. Common Stock 3.9% $1,116,360 210,634 EcoR1 Capital, LLC 31 Mar 2025
XNCR Xencor Inc Common Stock 2.9% $26,348,810 -$29,655,990 2,183,000 -53% EcoR1 Capital, LLC 31 Mar 2026
APLS Apellis Pharmaceuticals, Inc. Common Stock 2.7% $78,009,140 3,447,156 EcoR1 Capital, LLC 30 Sep 2025
WHWK Aadi Bioscience, Inc. Common Stock 1.4% $531,690 345,253 EcoR1 Capital, LLC 31 Dec 2024
TCRX TScan Therapeutics, Inc. Voting Common Stock 1.3% $1,060,533 662,833 EcoR1 Capital, LLC 31 Mar 2025
KLRS Kalaris Therapeutics, Inc. Common Stock 1.1% $1,315,201 201,718 EcoR1 Capital, LLC 31 Mar 2025
ARVN ARVINAS, INC. Common Stock 0% $0 0 EcoR1 Capital, LLC 31 Mar 2025
PRTA PROTHENA CORP PUBLIC LTD CO Ordinary Shares 0% $0 -$40,261,884 0 -100% EcoR1 Capital, LLC 27 May 2025
HLVX HilleVax, Inc. Common Stock 0% $0 -$6,044,280 0 -100% EcoR1 Capital, LLC 30 Sep 2025
MRSN Mersana Therapeutics, Inc. Common Stock 0% $0 -$4,168,241 0 -100% EcoR1 Capital, LLC 31 Mar 2025
VYGR Voyager Therapeutics, Inc. Common Stock 0% $0 -$15,450,989 0 -100% EcoR1 Capital, LLC 31 Mar 2026
QURE uniQure N.V. Ordinary Shares, par value(euro)0.05 per share 0% $0 -$84,954,515 0 -100% EcoR1 Capital, LLC 31 Dec 2025
TNGX Tango Therapeutics, Inc. Common Stock 0% $0 -$124,911,148 0 -100% EcoR1 Capital, LLC 31 Dec 2025
THRD Third Harmonic Bio, Inc. Common Stock 0% $0 0 EcoR1 Capital, LLC 31 Mar 2025
TECX Tectonic Therapeutic, Inc. Common Stock 0% $0 -$14,672,048 0 -100% EcoR1 Capital, LLC 30 Sep 2025

Schedules 13D/G Reported by EcoR1 Capital, LLC:

Sym Target Class Ownership Change Current shares Change Value Reporting name Form Report period Filing date
Schedule rows are parsed from SEC 13D/G filings. Open the linked filing or target page to verify the reported ownership and shares.
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