# EcoR1 Capital, LLC: Form 13F holdings

An institutional investment manager in San Francisco, CA. SEC CIK 1587114.

- Quarter ended: 2026-06-30
- Filed: 2026-08-14
- Reported value: $2.06bn
- Positions: 33 (33 lines in the filing's table; lines for the same security and option type are added together here)
- Compared with: the 13F for the quarter ended 2026-03-31
- Filing: https://www.sec.gov/Archives/edgar/data/1587114/000093583626000415/

## Holdings

As filed, largest first. Reported value is what the manager stated at the quarter end (Jun 30, 2026), in US dollars; it is filing data, not a price. Weight is the share of the total reported value.

| Issuer | Class | Reported value | Weight | Shares | Put or call | Change on the quarter before |
| --- | --- | ---: | ---: | ---: | --- | --- |
| [ZYMEWORKS INC (ZYME)](/companies/zyme.md) | COM | $600.4m | 29.2% | 22,970,388 |  | Unchanged |
| [ANAPTYSBIO INC (ANAB)](/companies/anab.md) | COM | $531.9m | 25.9% | 7,880,094 |  | Unchanged |
| [AKTIS ONCOLOGY INC (AKTS)](/companies/akts.md) | COM | $155.5m | 7.6% | 4,824,469 |  | Unchanged |
| [CG ONCOLOGY INC (CGON)](/companies/cgon.md) | COM | $106.2m | 5.2% | 1,494,300 |  | Added +392,300 |
| [ETON PHARMACEUTICALS INC (ETON)](/companies/eton.md) | COM | $78.6m | 3.8% | 2,171,938 |  | Unchanged |
| CRISPR THERAPEUTICS AG | NAMEN AKT | $75.8m | 3.7% | 1,389,276 |  | Unchanged |
| [ORIC PHARMACEUTICALS INC (ORIC)](/companies/oric.md) | COM | $72.9m | 3.5% | 6,728,116 |  | Unchanged |
| [FIRST TRACKS BIOTHERAPEUTICS (TRAX)](/companies/trax.md) | ORD SHS ADDED | $63.9m | 3.1% | 3,174,519 |  | New +3,174,519 |
| [LAKEFRONT BIOTHERAPEUTICS NV (LKFT)](/companies/lkft.md) | SPON ADR | $50.0m | 2.4% | 1,667,119 |  | Unchanged |
| [NEUROGENE INC (NGNE)](/companies/ngne.md) | COM | $40.0m | 1.9% | 1,271,342 |  | Unchanged |
| [CG ONCOLOGY INC (CGON)](/companies/cgon.md) | COM | $39.9m | 1.9% | 561,500 | Call | New +561,500 |
| [STOKE THERAPEUTICS INC (STOK)](/companies/stok.md) | COM | $24.0m | 1.2% | 735,000 |  | Added +635,000 |
| [FULCRUM THERAPEUTICS INC (FULC)](/companies/fulc.md) | COM | $24.0m | 1.2% | 6,549,866 |  | New +6,549,866 |
| [LEGEND BIOTECH CORP (LEGN)](/companies/legn.md) | SPONSORED ADS | $23.1m | 1.1% | 800,000 |  | New +800,000 |
| [BRIDGEBIO ONCOLOGY THERAPEUT (BBOT)](/companies/bbot.md) | COM NEW | $21.5m | 1.0% | 2,823,126 |  | Unchanged |
| [MBX BIOSCIENCES INC (MBX)](/companies/mbx.md) | COM | $21.4m | 1.0% | 388,500 |  | Reduced −388,500 |
| [ZENAS BIOPHARMA INC (ZBIO)](/companies/zbio.md) | COM | $20.0m | 1.0% | 789,500 |  | Unchanged |
| [ATARA BIOTHERAPEUTICS INC (ATRA)](/companies/atra.md) | COM NEW | $17.8m | 0.9% | 1,552,000 |  | Added +1,452,407 |
| [RELAY THERAPEUTICS INC (RLAY)](/companies/rlay.md) | COM | $13.1m | 0.6% | 697,948 |  | Reduced −1,206,814 |
| [AURA BIOSCIENCES INC (AURA)](/companies/aura.md) | COM | $11.8m | 0.6% | 1,666,667 |  | New +1,666,667 |
| [ODYSSEY THERAPEUTICS INC (ODTX)](/companies/odtx.md) | COMMON STOCK ADDED | $10.4m | 0.5% | 555,555 |  | New +555,555 |
| [EIKON THERAPEUTICS INC (EIKN)](/companies/eikn.md) | COM | $9.6m | 0.5% | 732,606 |  | Unchanged |
| PHARVARIS N V | COM | $8.1m | 0.4% | 235,000 |  | New +235,000 |
| ZURA BIO LTD | CLASS A ORD SHS | $7.0m | 0.3% | 1,179,715 |  | Unchanged |
| [PHATHOM PHARMACEUTICALS INC (PHAT)](/companies/phat.md) | COM | $6.8m | 0.3% | 625,000 |  | Unchanged |
| [NURIX THERAPEUTICS INC (NRIX)](/companies/nrix.md) | COM | $6.6m | 0.3% | 270,000 |  | New +270,000 |
| [ERASCA INC (ERAS)](/companies/eras.md) | COM | $6.0m | 0.3% | 330,000 |  | Reduced −570,000 |
| [ELOXX PHARMACEUTICALS INC (ELOX)](/companies/elox.md) | COM NEW ADDED | $5.6m | 0.3% | 400,000 |  | New +400,000 |
| [AARDVARK THERAPEUTICS INC (AARD)](/companies/aard.md) | COM | $2.3m | 0.1% | 396,194 |  | New +396,194 |
| HELIX ACQUISITION CORP III USD | CL A ORD SHS | $2.1m | 0.1% | 200,000 |  | Unchanged |
| [MEREO BIOPHARMA GROUP PLC (MREO)](/companies/mreo.md) | SPON ADS | $317.7k | <0.1% | 1,000,000 |  | Reduced −12,368,855 |
| SURROZEN INC | \*W EXP 08/01/203 | $115.3k | <0.1% | 4,444 |  | Unchanged |
| [AARDVARK THERAPEUTICS INC (AARD)](/companies/aard.md) | COM | $84.7k | <0.1% | 14,700 | Call | New +14,700 |

## Sold out

Held at the end of the quarter before and not reported this quarter.

| Issuer | Class | Reported value | Weight | Shares | Put or call | Change on the quarter before |
| --- | --- | ---: | ---: | ---: | --- | --- |
| CENTESSA PHARMACEUTICALS PLC | SPONSORED ADS | $0 | 0.0% | 0 | Call | Sold out −410,800 |
| CENTESSA PHARMACEUTICALS PLC | SPONSORED ADS | $0 | 0.0% | 0 |  | Sold out −6,000,000 |
| CRINETICS PHARMACEUTICALS IN | COM | $0 | 0.0% | 0 |  | Sold out −4,288,120 |
| [IBIO INC (IBIO)](/companies/ibio.md) | COM NEW | $0 | 0.0% | 0 |  | Sold out −1,583,000 |
| JAZZ PHARMACEUTICALS PLC | SHS USD | $0 | 0.0% | 0 |  | Sold out −1,706,469 |
| [PRELUDE THERAPEUTICS INC (PRLD)](/companies/prld.md) | COM | $0 | 0.0% | 0 |  | Sold out −947,049 |
| [REPLIMUNE GROUP INC (REPL)](/companies/repl.md) | COM | $0 | 0.0% | 0 |  | Sold out −1,000,000 |
| [XENCOR INC (XNCR)](/companies/xncr.md) | COM | $0 | 0.0% | 0 |  | Sold out −2,183,000 |

Source: SEC EDGAR, Form 13F-HR, accession 0000935836-26-000415. Last ingested by Listed: Oct 22, 2026, 05:26 ET. No prices; not investment advice.