Skip to content
Disclosery

EcoR1 Capital, LLC

Follow

13F filer, CIK 1587114, San Francisco, CA

EcoR1 Capital, LLC reported $1,689,330,628 across 37 holdings for the quarter ended 2025-06-30, in a 13F-HR filed 2025-08-14. Its ten largest share positions make up 77.42% of the portfolio.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0000935836-25-000506

Period
2025-06-30
Reported value
$1.69B
Holdings
37
Top 10 weight
77.42%
New
6
Sold out
15

Largest buys vs the previous quarter

SecurityShares changeApprox. value
ITEOS THERAPEUTICS INCnew+10,688,978$107M
ZYMEadded+5,710,840$71.7M
LKFTadded+881,939$24.7M
VERONA PHARMA PLCnew+200,000$18.9M
ALKSnew+500,000$14.3M

Ranked by the share change valued at this quarter's implied price (value over shares in the 13F). A position sold out is valued at the previous quarter's price, its last report.

Largest sells vs the previous quarter

SecurityShares changeApprox. value
PRTAexited-11,584,280-$143M
SRPTexited-1,292,386-$82.5M
ORICreduced-1,800,000-$18.3M
BEAMexited-526,685-$10.3M
DNAexited-1,462,328-$8.34M

Ranked by the share change valued at this quarter's implied price (value over shares in the 13F). A position sold out is valued at the previous quarter's price, its last report.

Holdings, Q2 2025

Share positions as resolved from 13F-HR 0000935836-25-000506, largest first. % of portfolio is the value over $1,686,852,743, the sum of the share positions whose value is usable for ratios (method).

SecurityHistorySharesValue% of portfolioChangeLatest eventTimeline
ZYMEZYMEWORKS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 13,437,473 shares; 2024Q4: 15,028,079 shares; 2025Q1: 17,259,548 shares; 2025Q2: 22,970,388 shares 22,970,388$288M17.09%+5,710,840Timeline
APLSAPELLIS PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 11,890,843 shares; 2024Q4: 11,890,843 shares; 2025Q1: 11,895,808 shares; 2025Q2: 11,895,808 shares 11,895,808$206M12.21%0Timeline
JAZZJAZZ PHARMACEUTICALS PLCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,706,469 shares; 2024Q4: 1,706,469 shares; 2025Q1: 1,706,469 shares; 2025Q2: 1,706,469 shares 1,706,469$181M10.74%0Timeline
ANABANAPTYSBIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 7,794,996 shares; 2024Q4: 7,873,448 shares; 2025Q1: 7,880,094 shares; 2025Q2: 7,880,094 shares 7,880,094$175M10.37%0Timeline
CRNXCRINETICS PHARMACEUTICALS INQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 4,288,120 shares; 2024Q4: 4,288,120 shares; 2025Q1: 4,288,120 shares; 2025Q2: 4,288,120 shares 4,288,120$123M7.31%0Timeline
ITEOS THERAPEUTICS INCITEOS THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,608,616 shares; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 10,688,978 shares 10,688,978$107M6.32%new
CRSPCRISPR THERAPEUTICS AGQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,389,276 shares; 2024Q4: 1,389,276 shares; 2025Q1: 1,389,276 shares; 2025Q2: 1,389,276 shares 1,389,276$67.6M4.01%0Timeline
QUREUNIQURE NVQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: 3,400,000 shares; 2025Q1: 3,988,971 shares; 2025Q2: 3,988,971 shares 3,988,971$55.6M3.3%0Timeline
TNGXTANGO THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 13,330,736 shares; 2024Q4: 10,630,736 shares; 2025Q1: 10,630,736 shares; 2025Q2: 10,630,736 shares 10,630,736$54.4M3.23%0Timeline
XNCRXENCOR INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 5,330,416 shares; 2024Q4: 6,144,767 shares; 2025Q1: 6,144,767 shares; 2025Q2: 6,144,767 shares 6,144,767$48.3M2.86%0Timeline
IMNMIMMUNOME INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 3,879,415 shares; 2024Q4: 3,879,415 shares; 2025Q1: 4,079,415 shares; 2025Q2: 4,079,415 shares 4,079,415$37.9M2.25%0Timeline
JANXJANUX THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,469,818 shares; 2024Q4: 1,469,818 shares; 2025Q1: 1,469,818 shares; 2025Q2: 1,469,818 shares 1,469,818$34M2.01%0Timeline
LKFTLAKEFRONT BIOTHERAPEUTICS NVQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 155,006 shares; 2024Q4: 155,006 shares; 2025Q1: 155,006 shares; 2025Q2: 1,036,945 shares 1,036,945$29M1.72%+881,939Timeline
ETONETON PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 566,075 shares; 2024Q4: 1,829,603 shares; 2025Q1: 1,939,288 shares; 2025Q2: 2,030,544 shares 2,030,544$28.9M1.72%+91,256Timeline
KURAKURA ONCOLOGY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 5,806,871 shares; 2024Q4: 3,557,269 shares; 2025Q1: 2,640,298 shares; 2025Q2: 4,200,000 shares 4,200,000$24.2M1.44%+1,559,702Timeline
AKROAKERO THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 440,000 shares; 2025Q2: 440,000 shares 440,000$23.5M1.39%0Timeline
MDGLMADRIGAL PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 75,000 shares; 2024Q4: 75,000 shares; 2025Q1: 75,000 shares; 2025Q2: 75,000 shares 75,000$22.7M1.35%0Timeline
NGNENEUROGENE INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,271,342 shares; 2024Q4: 1,271,342 shares; 2025Q1: 1,271,342 shares; 2025Q2: 1,271,342 shares 1,271,342$19M1.13%0Timeline
VERONA PHARMA PLCVERONA PHARMA PLCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 200,000 shares 200,000$18.9M1.12%new
TECXTECTONIC THERAPEUTIC INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 849,143 shares; 2024Q4: 849,143 shares; 2025Q1: 935,121 shares; 2025Q2: 935,121 shares 935,121$18.6M1.1%0Timeline
ORICORIC PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 3,418,068 shares; 2024Q4: 3,418,068 shares; 2025Q1: 3,418,068 shares; 2025Q2: 1,618,068 shares 1,618,068$16.4M0.97%-1,800,000Timeline
ALKSALKERMES PLCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 500,000 shares 500,000$14.3M0.85%newTimeline
RNAMAVIDITY BIOSCIENCES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 757,576 shares; 2024Q4: 557,576 shares; 2025Q1: 557,576 shares; 2025Q2: 500,000 shares 500,000$14.2M0.84%-57,576Timeline
MBXMBX BIOSCIENCES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,175,809 shares; 2024Q4: 1,259,273 shares; 2025Q1: 1,259,273 shares; 2025Q2: 1,149,794 shares 1,149,794$13.1M0.78%-109,479Timeline
VYGRVOYAGER THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 3,917,546 shares; 2024Q4: 3,917,546 shares; 2025Q1: 3,917,546 shares; 2025Q2: 3,917,546 shares 3,917,546$12.2M0.72%0Timeline
PCRXPACIRA BIOSCIENCES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 457,471 shares 457,471$10.9M0.65%newTimeline
REPLREPLIMUNE GROUP INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 850,341 shares; 2024Q4: 850,341 shares; 2025Q1: 850,341 shares; 2025Q2: 850,341 shares 850,341$7.9M0.47%0Timeline
MTSRMETSERA INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 50,000 shares; 2025Q2: 271,529 shares 271,529$7.72M0.46%+221,529Timeline
ADAPYADAPTIMMUNE THERAPEUTICS PLC SQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 27,404,070 shares; 2024Q4: 27,404,070 shares; 2025Q1: 27,404,070 shares; 2025Q2: 27,404,070 shares 27,404,070$6.57M0.39%0Timeline
DAWNDAY ONE BIOPHARMACEUTICALS IQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 862,068 shares; 2024Q4: 862,068 shares; 2025Q1: 862,068 shares; 2025Q2: 862,068 shares 862,068$5.6M0.33%0Timeline
HILLEVAX INCHILLEVAX INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 2,420,243 shares 2,420,243$4.82M0.29%new
ATRAATARA BIOTHERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 468,938 shares; 2024Q4: 532,134 shares; 2025Q1: 573,183 shares; 2025Q2: 573,183 shares 573,183$4.42M0.26%0Timeline
WHWKWHITEHAWK THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,845,253 shares; 2024Q4: 345,253 shares; 2025Q1: 2,082,000 shares; 2025Q2: 1,091,417 shares 1,091,417$2.04M0.12%-990,583Timeline
MGNXMACROGENICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 56,018 shares; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 1,602,717 shares 1,602,717$1.94M0.11%newTimeline
NUVATION BIO INCNUVATION BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 963,333 shares; 2024Q4: 963,333 shares; 2025Q1: 963,333 shares; 2025Q2: 963,333 shares 963,333$1.88M0.11%0
SRZNWSURROZEN INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 66,665 shares; 2024Q4: 66,665 shares; 2025Q1: 66,665 shares; 2025Q2: 66,665 shares 66,665$596K0Value about 1,000 times the price other filers imply, kept as filed and left out of ratios.Timeline

Options

Puts and calls, as filed. The amount and value describe the underlying shares, not the option premium, so they stay out of % of portfolio (H5).

SecurityTypeAmountValueChange
QUREUNIQURE NV SHScall135,000$1.88M0

Sold out in Q2 2025

Positions in the previous quarter's report that this quarter's report no longer lists.

SecurityShares beforeValue beforeType
PRTAPROTHENA CORP PLC11,584,280$143Mshares
SRPTSAREPTA THERAPEUTICS INC1,292,386$82.5Mshares
BEAMBEAM THERAPEUTICS INC526,685$10.3Mshares
DNAGINKGO BIOWORKS HOLDINGS INC1,462,328$8.34Mshares
BCYCBICYCLE THERAPEUTICS PLC910,000$7.73Mshares
VERVE THERAPEUTICS INCVERVE THERAPEUTICS INC1,250,000$5.71Mshares
SLDBSOLID BIOSCIENCES INC744,450$2.75Mshares
KROSKEROS THERAPEUTICS INC187,500$1.91Mshares
RLAYRELAY THERAPEUTICS INC641,426$1.68Mshares
KLRSKALARIS THERAPEUTICS INC201,718$1.62Mshares
PRMEPRIME MEDICINE INC700,000$1.39Mshares
TCRXTSCAN THERAPEUTICS INC662,833$915Kshares
ALGSALIGOS THERAPEUTICS INC88,569$731Kshares
ETONETON PHARMACEUTICALS INC50,500$655Kcall
UPBUPSTREAM BIO INC60,000$367Kshares

How Q2 2025 was built

Available 13F filings of this filer for the quarter and their roles: the base report is the latest original or restatement, NEW HOLDINGS amendments filed after it are added (method).

FilingRoleAmendmentFiledAcceptedIngested
13F-HR 0000935836-25-000506 base2025-08-14acceptance time not in the bulk data set