EcoR1 Capital, LLC
Clone Performance
Jul 2023–Jul 2026 · vs SPYHypothetical growth of buying every stock this filer reported holding, rebalancing on each filing and indexed to the same start. Option positions cannot be bought this way and are left out.
Estimate. 13F holdings are quarter-lagged, so the clone rebalances about 45 days after each period end — when the filing becomes public — and it excludes option and short positions. It tracks 99% of reported value on average across 13 quarters. Past performance does not predict future results.
Portfolio Concentration
28 tracked positions · as of Mar 31, 2026 · Δ vs Dec 31, 2025Portfolio Trend
Sector Breakdown
As of Mar 31, 2026| Sector | % Portfolio | Value |
|---|---|---|
| Healthcare | 99.9% | $2,354,156,984 |
| Financial Services | 0.1% | $2,032,000 |
Last Quarter's Activity
Export CSVAdded To
Positions the filer increased| Ticker | Company | Δ Shares | Shares | Value | Open |
|---|---|---|---|---|---|
| MREO | Mereo BioPharma Group plc | +5,512,389 | 13,368,855 | $4,411,722 | |
| CNTA | Centessa Pharmaceuticals plc | +3,295,800 | 6,410,800 | $254,636,976 | |
| ETON | Eton Pharmaceuticals, Inc. | +141,394 | 2,171,938 | $53,603,429 | |
| CGON | CG Oncology, Inc. | +37,200 | 1,102,000 | $74,583,360 | |
| No positions match the current search. | |||||
Trimmed
Positions the filer reducedNew Positions
Positions the filer opened this quarter| Ticker | Company | Shares | Value | Open |
|---|---|---|---|---|
| AKTS | Aktis Oncology, Inc. | 4,824,469 | $86,309,750 | |
| RLAY | Relay Therapeutics, Inc. | 1,904,762 | $18,952,381 | |
| ERAS | Erasca, Inc. | 900,000 | $14,562,000 | |
| EIKN | Eikon Therapeutics, Inc. | 732,606 | $7,750,971 | |
| REPL | Replimune Group, Inc. | 1,000,000 | $7,650,000 | |
| ZURA | Zura Bio Ltd | 1,179,715 | $7,019,304 | |
| PHAT | Phathom Pharmaceuticals, Inc. | 625,000 | $6,943,750 | |
| STOK | Stoke Therapeutics, Inc. | 100,000 | $3,256,000 | |
| PRLD | Prelude Therapeutics Inc | 947,049 | $3,238,907 | |
| HLXC | Helix Acquisition Corp. III | 200,000 | $2,032,000 | |
| No positions match the current search. | ||||
Sold Out
Positions the filer fully exited| Ticker | Company | Shares | Value | Open |
|---|---|---|---|---|
| IMNM | Immunome Inc. | 2,855,590 | $61,338,073 | |
| GPCR | Structure Therapeutics Inc. | 334,380 | $23,256,129 | |
| PCVX | Vaxcyte, Inc. | 450,000 | $20,763,000 | |
| AQST | Aquestive Therapeutics, Inc. | 2,625,000 | $16,957,500 | |
| VYGR | Voyager Therapeutics, Inc. | 4,002,847 | $15,731,188 | |
| MNKD | Mannkind Corp | 1,660,000 | $9,412,200 | |
| EOLS | Evolus, Inc. | 675,000 | $4,488,750 | |
| CAMP | Camp4 Therapeutics Corp | 325,000 | $1,992,250 | |
| No positions match the current search. | ||||
| Ticker | Company | Type | Shares | Value (USD) | % of Portfolio | History |
|---|---|---|---|---|---|---|
| ZYME |
Zymeworks Inc.
Healthcare
|
Held | 22,970,388 | $575,178,515 | 24.41% | |
| ANAB |
Anaptysbio, Inc
Healthcare
|
Held | 7,880,094 | $437,029,619 | 18.55% | |
| JAZZ |
Jazz Pharmaceuticals plc
Healthcare
|
Held | 1,706,469 | $322,607,964 | 13.69% | |
| CNTA |
Centessa Pharmaceuticals plc
CALL
+ SHARES
Healthcare
|
Added | 6,410,800 | $254,636,976 | 10.81% | |
| CRNX |
Crinetics Pharmaceuticals, Inc.
Healthcare
|
Held | 4,288,120 | $155,744,518 | 6.61% | |
| AKTS |
Aktis Oncology, Inc.
Healthcare
|
NEW | 4,824,469 | $86,309,750 | 3.66% | |
| ORIC |
Oric Pharmaceuticals, Inc.
Healthcare
|
Held | 6,728,116 | $85,245,229 | 3.62% | |
| CGON |
CG Oncology, Inc.
Healthcare
|
Added | 1,102,000 | $74,583,360 | 3.17% | |
| CRSP |
CRISPR Therapeutics AG
Healthcare
|
Held | 1,389,276 | $66,087,859 | 2.80% | |
| ETON |
Eton Pharmaceuticals, Inc.
Healthcare
|
Added | 2,171,938 | $53,603,429 | 2.28% | |
| LKFT |
Lakefront Biotherapeutics NV
Healthcare
|
Held | 1,667,119 | $50,013,570 | 2.12% | |
| XNCR |
Xencor Inc
Healthcare
|
Reduced | 2,183,000 | $26,326,980 | 1.12% | |
| NGNE |
Neurogene Inc.
Healthcare
|
Held | 1,271,342 | $25,630,254 | 1.09% | |
| BBOT |
BridgeBio Oncology Therapeutics, Inc.
Healthcare
|
Held | 2,823,126 | $25,266,977 | 1.07% | |
| MBX |
MBX Biosciences, Inc.
Healthcare
|
Reduced | 777,000 | $23,193,450 | 0.98% | |
| RLAY |
Relay Therapeutics, Inc.
Healthcare
|
NEW | 1,904,762 | $18,952,381 | 0.80% | |
| ZBIO |
Zenas BioPharma, Inc.
Healthcare
|
Held | 789,500 | $15,434,725 | 0.66% | |
| ERAS |
Erasca, Inc.
Healthcare
|
NEW | 900,000 | $14,562,000 | 0.62% | |
| EIKN |
Eikon Therapeutics, Inc.
Healthcare
|
NEW | 732,606 | $7,750,971 | 0.33% | |
| REPL |
Replimune Group, Inc.
Healthcare
|
NEW | 1,000,000 | $7,650,000 | 0.32% | |
| ZURA |
Zura Bio Ltd
Healthcare
|
NEW | 1,179,715 | $7,019,304 | 0.30% | |
| PHAT |
Phathom Pharmaceuticals, Inc.
Healthcare
|
NEW | 625,000 | $6,943,750 | 0.29% | |
| MREO |
Mereo BioPharma Group plc
Healthcare
|
Added | 13,368,855 | $4,411,722 | 0.19% | |
| STOK |
Stoke Therapeutics, Inc.
Healthcare
|
NEW | 100,000 | $3,256,000 | 0.14% | |
| PRLD |
Prelude Therapeutics Inc
Healthcare
|
NEW | 947,049 | $3,238,907 | 0.14% | |
| IBIO |
iBio, Inc.
Healthcare
|
Reduced | 1,583,000 | $3,007,700 | 0.13% | |
| HLXC |
Helix Acquisition Corp. III
Financial Services
|
NEW | 200,000 | $2,032,000 | 0.09% | |
| ATRA |
Atara Biotherapeutics, Inc.
Healthcare
|
Reduced | 99,593 | $471,074 | 0.02% |
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.