EcoR1 Capital, LLC
CIK
1587114
Location
San Francisco, CA
Portfolio Value
Mid
$2,056,618,430
Diversification
Moderately concentrated
Filing Date
Global Rank
#1,314
/ 8,700
▲ 93
Top Industry
Biotechnology
96.1%
Period ended 2 months ago
Filed Aug 14, 2026 · 30d
26 quarters · since Mar 2020
Portfolio Concentration
31 tracked positions · as of Jun 30, 2026 · Δ vs Mar 31, 2026Top Position
29.2%
+1.8 pts
Top 5
73.5%
−1.5 pts
Top 10
88.3%
−2.5 pts
HHI
1,699
Moderately concentrated+150
Portfolio Trend
26 quarters · across all stocks
Sector Breakdown
As of Jun 30, 2026| Sector | % Portfolio | Value |
|---|---|---|
| Healthcare | 99.9% | $2,054,490,430 |
| Financial Services | 0.1% | $2,128,000 |
Last Quarter's Activity
Export CSVAdded To
Positions the filer increased
3 positions
Trimmed
Positions the filer reduced
4 positions
| Ticker | Company | Δ Shares | Shares | Value | Open |
|---|---|---|---|---|---|
| MREO | Mereo BioPharma Group plc | −12,368,855 | 1,000,000 | $318,000 | |
| RLAY | Relay Therapeutics, Inc. | −1,206,814 | 697,948 | $13,058,607 | |
| ERAS | Erasca, Inc. | −570,000 | 330,000 | $6,045,600 | |
| MBX | MBX Biosciences, Inc. | −388,500 | 388,500 | $21,445,200 | |
| No positions match the current search. | |||||
New Positions
Positions the filer opened this quarter
9 positions
| Ticker | Company | Shares | Value | Open |
|---|---|---|---|---|
| TRAX | First Tracks Biotherapeutics, Inc. | 3,174,519 | $63,871,322 | |
| FULC | Fulcrum Therapeutics, Inc. | 6,549,866 | $23,972,509 | |
| LEGN | Legend Biotech Corp | 800,000 | $23,104,000 | |
| AURA | Aura Biosciences, Inc. | 1,666,667 | $11,833,335 | |
| ODTX | Odyssey Therapeutics, Inc. | 555,555 | $10,394,434 | |
| PHVS | Pharvaris N.V. | 235,000 | $8,126,300 | |
| NRIX | Nurix Therapeutics, Inc. | 270,000 | $6,550,200 | |
| ELOX | Eloxx Pharmaceuticals, Inc. | 400,000 | $5,552,000 | |
| AARD | Aardvark Therapeutics, Inc. | 410,894 | $2,366,749 | |
| No positions match the current search. | ||||
Sold Out
Positions the filer fully exited
7 positions
| Ticker | Company | Shares | Value | Open |
|---|---|---|---|---|
| JAZZ | Jazz Pharmaceuticals plc | 1,706,469 | $322,607,964 | |
| CRNX | Crinetics Pharmaceuticals, Inc. | 4,288,120 | $155,744,518 | |
| XNCR | Xencor Inc | 2,183,000 | $26,326,980 | |
| REPL | Replimune Group, Inc. | 1,000,000 | $7,650,000 | |
| PRLD | Prelude Therapeutics Inc | 947,049 | $3,238,907 | |
| IBIO | iBio, Inc. | 1,583,000 | $3,007,700 | |
| CNTA | Centessa Pharmaceuticals plc | 6,410,800 | $0 | |
| No positions match the current search. | ||||
31 tracked positions ·
$2,056,618,430 total
· filing declares
33 positions · $2,056,733,459
· as of Jun 30, 2026
| Ticker | Company | Type | Shares | Value (USD) | % of Portfolio | History |
|---|---|---|---|---|---|---|
| ZYME |
Zymeworks Inc.
Healthcare
|
Held | 22,970,388 | $600,445,942 | 29.20% | |
| ANAB |
Anaptysbio, Inc
Healthcare
|
Held | 7,880,094 | $531,906,345 | 25.86% | |
| AKTS |
Aktis Oncology, Inc.
Healthcare
|
Held | 4,824,469 | $155,492,635 | 7.56% | |
| CGON |
CG Oncology, Inc.
CALL
+ SHARES
Healthcare
|
Added | 2,055,800 | $146,064,590 | 7.10% | |
| ETON |
Eton Pharmaceuticals, Inc.
Healthcare
|
Held | 2,171,938 | $78,624,155 | 3.82% | |
| CRSP |
CRISPR Therapeutics AG
Healthcare
|
Held | 1,389,276 | $75,771,113 | 3.68% | |
| ORIC |
Oric Pharmaceuticals, Inc.
Healthcare
|
Held | 6,728,116 | $72,865,496 | 3.54% | |
| TRAX |
First Tracks Biotherapeutics, Inc.
Healthcare
|
NEW | 3,174,519 | $63,871,322 | 3.11% | |
| LKFT |
Lakefront Biotherapeutics NV
Healthcare
|
Held | 1,667,119 | $49,980,227 | 2.43% | |
| NGNE |
Neurogene Inc.
Healthcare
|
Held | 1,271,342 | $39,983,705 | 1.94% | |
| STOK |
Stoke Therapeutics, Inc.
Healthcare
|
Added | 735,000 | $24,049,200 | 1.17% | |
| FULC |
Fulcrum Therapeutics, Inc.
Healthcare
|
NEW | 6,549,866 | $23,972,509 | 1.17% | |
| LEGN |
Legend Biotech Corp
Healthcare
|
NEW | 800,000 | $23,104,000 | 1.12% | |
| BBOT |
BridgeBio Oncology Therapeutics, Inc.
Healthcare
|
Held | 2,823,126 | $21,512,220 | 1.05% | |
| MBX |
MBX Biosciences, Inc.
Healthcare
|
Reduced | 388,500 | $21,445,200 | 1.04% | |
| ZBIO |
Zenas BioPharma, Inc.
Healthcare
|
Held | 789,500 | $20,037,510 | 0.97% | |
| ATRA |
Atara Biotherapeutics, Inc.
Healthcare
|
Added | 1,552,000 | $17,816,960 | 0.87% | |
| RLAY |
Relay Therapeutics, Inc.
Healthcare
|
Reduced | 697,948 | $13,058,607 | 0.63% | |
| AURA |
Aura Biosciences, Inc.
Healthcare
|
NEW | 1,666,667 | $11,833,335 | 0.58% | |
| ODTX |
Odyssey Therapeutics, Inc.
Healthcare
|
NEW | 555,555 | $10,394,434 | 0.51% | |
| EIKN |
Eikon Therapeutics, Inc.
Healthcare
|
Held | 732,606 | $9,560,508 | 0.46% | |
| PHVS |
Pharvaris N.V.
Healthcare
|
NEW | 235,000 | $8,126,300 | 0.40% | |
| ZURA |
Zura Bio Ltd
Healthcare
|
Held | 1,179,715 | $6,960,318 | 0.34% | |
| PHAT |
Phathom Pharmaceuticals, Inc.
Healthcare
|
Held | 625,000 | $6,781,250 | 0.33% | |
| NRIX |
Nurix Therapeutics, Inc.
Healthcare
|
NEW | 270,000 | $6,550,200 | 0.32% | |
| ERAS |
Erasca, Inc.
Healthcare
|
Reduced | 330,000 | $6,045,600 | 0.29% | |
| ELOX |
Eloxx Pharmaceuticals, Inc.
Healthcare
|
NEW | 400,000 | $5,552,000 | 0.27% | |
| AARD |
Aardvark Therapeutics, Inc.
CALL
+ SHARES
Healthcare
|
NEW | 410,894 | $2,366,749 | 0.12% | |
| HLXC |
Helix Acquisition Corp. III
Financial Services
|
Held | 200,000 | $2,128,000 | 0.10% | |
| MREO |
Mereo BioPharma Group plc
Healthcare
|
Reduced | 1,000,000 | $318,000 | 0.02% | |
| SRZN |
Surrozen, Inc./DE
Healthcare
|
Held | 4,444 | $0 | 0.00% |
Covers the securities this platform tracks: U.S.-listed common stock and the put/call positions reported on it. A 13F can also report security types outside that coverage — preferred shares, bonds, warrants, untracked share classes — so the filing's own declared total can exceed the figures above. The source filing is linked at the top of this table.