EcoR1 Capital, LLC
CIK 1587114 · View on SEC EDGAR ↗
- Portfolio value
- $2.1B
- Positions
- 33
- As of
- June 30, 2026
#1,484 of 9,443 by 13F value · top 15.7%
Portfolio value QoQ: -12.7% 13F does not disclose cash
- Top 10 holdings weight
- 86.31%
- Top 25 holdings weight
- 98.88%
- Positions above 1%
- 16
- Effective number of positions
- 6.0
Based on 13F long-equity holdings only (cash, bonds, shorts not disclosed)
Turnover Q2 2026: 11.83% Est. buys $260,989,173 · sells $831,609,721
Median holding: 2.0 quarters Tracked Q4 2024–Q2 2026 · 31.4% still held
- New positions
- 11
- Increased
- 3
- Decreased
- 4
- Closed
- 7
On this page
- Performance vs S&P How this manager's 13F portfolio performed against the S&P 500.
- Sector breakdown How the portfolio splits across market sectors.
- Portfolio Every stock this institution reports holding, from its latest 13F.
- Biggest new bets Brand-new positions opened in the latest quarter.
- Top moves The biggest position increases and decreases this quarter.
- Exited positions Positions the manager fully sold out of last quarter.
- Related The person behind this filer, where we can match one.
Performance vs S&P 500
Annualized: +23.1% · S&P 500: +18.0%
Approximates a buy-and-hold portfolio built from quarterly SEC 13F snapshots. Excludes cash, short positions, options/derivatives, and non-13(f) securities — reflects the disclosed long-equity book only, not total fund AUM. SEC filing lag is up to 45 days; this is not a real-time-copyable timing.
Priceable coverage: 97.2% · Options excluded: 1.4%
Sector breakdown
Healthcare
88.0%
Other/Unmapped
12.0%
Full portfolio 33 positions
| Type | Streak | 8Q trend | |||||
|---|---|---|---|---|---|---|---|
| ZYME Zymeworks Inc. - Common Stock | $600,445,942 | 29.19% | 22,970,388 | $25,267,426 | |||
| ANAB AnaptysBio, Inc. - Common Stock | $531,906,345 | 25.86% | 7,880,094 | $94,876,332 | |||
| AKTS Aktis Oncology, Inc. - Common stock | $155,492,636 | 7.56% | 4,824,469 | $69,182,886 | |||
| CGON CG Oncology, Inc. - Common stock | $106,170,015 | 5.16% | 1,494,300 | $31,586,655 | Up ×2 | ||
| ETON Eton Pharmaceuticals, Inc. - Common Stock | $78,624,156 | 3.82% | 2,171,938 | $25,020,726 | |||
| CRSP CRISPR Therapeutics AG - Common Shares | $75,771,113 | 3.68% | 1,389,276 | $9,683,254 | |||
| ORIC Oric Pharmaceuticals, Inc. - Common Stock | $72,865,496 | 3.54% | 6,728,116 | $-12,379,734 | |||
| Unknown issuer (CUSIP: 337185102) | $63,871,322 | 3.11% | 3,174,519 | Up ×1 | |||
| GLPG Galapagos NV - American Depositary Shares | $49,980,228 | 2.43% | 1,667,119 | $-33,342 | |||
| NGNE Neurogene Inc. - Common Stock | $39,983,706 | 1.94% | 1,271,342 | $14,353,451 | |||
| CGON CG Oncology, Inc. - Common stock | $39,894,575 | 1.94% | 561,500 | Call option | |||
| STOK Stoke Therapeutics, Inc. - Common Stock | $24,049,200 | 1.17% | 735,000 | $20,793,200 | Up ×1 | ||
| FULC Fulcrum Therapeutics, Inc. - Common Stock | $23,972,510 | 1.17% | 6,549,866 | Up ×1 | |||
| LEGN Legend Biotech Corporation - American Depositary Shares | $23,104,000 | 1.12% | 800,000 | Up ×1 | |||
| BBOT BridgeBio Oncology Therapeutics, Inc. - Common Stock | $21,512,220 | 1.05% | 2,823,126 | $-3,754,758 | |||
| MBX MBX Biosciences, Inc. - Common Stock | $21,445,200 | 1.04% | 388,500 | $-1,748,250 | Down ×2 | ||
| ZBIO Zenas BioPharma, Inc. - Common Stock | $20,037,510 | 0.97% | 789,500 | $4,602,785 | |||
| ATRA Atara Biotherapeutics, Inc. - Common Stock | $17,816,960 | 0.87% | 1,552,000 | $17,345,885 | Up ×1 | ||
| RLAY Relay Therapeutics, Inc. - Common Stock | $13,058,607 | 0.63% | 697,948 | $-5,893,775 | Down ×1 | ||
| AURA Aura Biosciences, Inc. - Common Stock | $11,833,336 | 0.58% | 1,666,667 | Up ×1 | |||
| Unknown issuer (CUSIP: 67613T104) | $10,394,434 | 0.51% | 555,555 | Up ×1 | |||
| EIKN Eikon Therapeutics, Inc. - Common Stock | $9,560,508 | 0.46% | 732,606 | $1,809,537 | |||
| PHVS Pharvaris N.V. - Ordinary Shares | $8,126,300 | 0.40% | 235,000 | Up ×1 | |||
| ZURA Zura Bio Limited - Class A Ordinary shares | $6,960,319 | 0.34% | 1,179,715 | $-58,985 | |||
| PHAT Phathom Pharmaceuticals, Inc. - Common Stock | $6,781,250 | 0.33% | 625,000 | $-162,500 | |||
| NRIX Nurix Therapeutics, Inc. - Common stock | $6,550,200 | 0.32% | 270,000 | Up ×1 | |||
| ERAS Erasca, Inc. - Common Stock | $6,045,600 | 0.29% | 330,000 | $-8,516,400 | Down ×1 | ||
| Unknown issuer (CUSIP: 29014R301) | $5,552,000 | 0.27% | 400,000 | Up ×1 | |||
| AARD Aardvark Therapeutics, Inc. - Common Stock | $2,282,077 | 0.11% | 396,194 | Up ×1 | |||
| HLXC Helix Acquisition Corp. III - Class A Ordinary Shares | $2,128,000 | 0.10% | 200,000 | $96,000 | |||
| MREO Mereo BioPharma Group plc - American Depositary Shares | $317,700 | 0.02% | 1,000,000 | $-4,094,022 | Down ×1 | ||
| SRZNW Surrozen, Inc. - Warrant | $115,322 | 0.01% | 4,444 | $-14,132 | |||
| AARD Aardvark Therapeutics, Inc. - Common Stock | $84,672 | 0.00% | 14,700 | Call option | Up ×1 | ||
| No matches | |||||||
Biggest new bets
New positions opened this quarter, largest first.
| Security | Value | Shares | % of portfolio |
|---|---|---|---|
| Unknown issuer (CUSIP: 337185102) | $63,871,322 | 3,174,519 | 3.11% |
| CGON | $39,894,575 | 561,500 | 1.94% |
| FULC | $23,972,510 | 6,549,866 | 1.17% |
| LEGN | $23,104,000 | 800,000 | 1.12% |
| AURA | $11,833,336 | 1,666,667 | 0.58% |
| Unknown issuer (CUSIP: 67613T104) | $10,394,434 | 555,555 | 0.51% |
| PHVS | $8,126,300 | 235,000 | 0.40% |
| NRIX | $6,550,200 | 270,000 | 0.32% |
| Unknown issuer (CUSIP: 29014R301) | $5,552,000 | 400,000 | 0.27% |
| AARD | $2,282,077 | 396,194 | 0.11% |
| AARD | $84,672 | 14,700 | 0.00% |
Top movers (QoQ)
| Security | Action | Shares Δ | Value Δ |
|---|---|---|---|
| ANAB | Price move only | +0 | +$94.9M |
| AKTS | Price move only | +0 | +$69.2M |
| CGON | Bought more | +392K | +$31.6M |
| ZYME | Price move only | +0 | +$25.3M |
| ETON | Price move only | +0 | +$25.0M |
| NGNE | Price move only | +0 | +$14.4M |
| ORIC | Price move only | +0 | -$12.4M |
| CRSP | Price move only | +0 | +$9.7M |
| ERAS | Trimmed | -570K | -$8.5M |
| RLAY | Trimmed | -1.2M | -$5.9M |
2 positions hidden (data completeness check)
Exited positions
Includes corporate events (mergers, delistings) — not all exits are sells
Closed positions reflect 13F reporting changes; for index managers these are often mechanical (delisting, M&A, index rebalancing), not active decisions.
| Security | Quarter | Shares before | Value before | Price since exit |
|---|---|---|---|---|
| JAZZ | June 30, 2026 | 1,706,469 | $322,607,964 | 4.3% |
| CNTA | June 30, 2026 | 6,410,800 | $254,636,976 | No longer tracked |
| QURE | Dec. 31, 2025 | 3,988,971 | $232,836,237 | 100.2% |
| CRNX | June 30, 2026 | 4,288,120 | $155,744,518 | 126.4% |
| PRTA | June 30, 2025 | 11,584,280 | $143,355,465 | 47.6% |
| PFE | March 31, 2025 | 5,000,000 | $132,650,000 | 9.8% |
| ARVN | March 31, 2025 | 6,726,491 | $128,946,832 | 34.9% |
| ITOS | Sept. 30, 2025 | 10,688,978 | $106,569,111 | No longer tracked |
| TNGX | Dec. 31, 2025 | 10,630,736 | $89,298,182 | 175.6% |
| SRPT | June 30, 2025 | 1,292,386 | $82,480,075 | 12.0% |
| APLS | Dec. 31, 2025 | 3,447,156 | $78,009,140 | No longer tracked |
| IMNM | March 31, 2026 | 2,855,590 | $61,338,073 | 30.7% |
| SWTX | March 31, 2025 | 1,560,000 | $56,362,800 | No longer tracked |
| MDGL | Dec. 31, 2025 | 75,000 | $34,399,500 | -7.9% |
| JANX | Sept. 30, 2025 | 1,469,818 | $33,952,796 | -28.8% |
| RNA | Dec. 31, 2025 | 765,000 | $33,331,050 | -81.1% |
| THRD | March 31, 2025 | 3,182,444 | $32,747,349 | No longer tracked |
| XNCR | June 30, 2026 | 2,183,000 | $26,326,980 | 66.4% |
| AKRO | Sept. 30, 2025 | 440,000 | $23,478,400 | No longer tracked |
| GPCR | March 31, 2026 | 334,380 | $23,256,129 | 10.5% |
| NMRA | March 31, 2025 | 2,071,450 | $21,957,370 | 59.0% |
| CRGX | March 31, 2025 | 1,470,000 | $21,197,400 | No longer tracked |
| PCVX | March 31, 2026 | 450,000 | $20,763,000 | 6.0% |
| VRNA | Sept. 30, 2025 | 200,000 | $18,916,000 | No longer tracked |
| TECX | Sept. 30, 2025 | 935,121 | $18,580,854 | 130.5% |
| MLTX | March 31, 2025 | 332,522 | $18,006,066 | -58.1% |
| AQST | March 31, 2026 | 2,625,000 | $16,957,500 | 9.6% |
| MRSN | March 31, 2025 | 11,328,000 | $16,199,040 | No longer tracked |
| VYGR | March 31, 2026 | 4,002,847 | $15,731,189 | -12.7% |
| ALKS | Dec. 31, 2025 | 500,000 | $15,000,000 | 76.3% |
| MTSR | Dec. 31, 2025 | 271,529 | $14,209,113 | No longer tracked |
| KYMR | March 31, 2025 | 350,000 | $14,080,500 | 354.3% |
| DYN | March 31, 2025 | 555,644 | $13,090,973 | 148.8% |
| AVIR | March 31, 2025 | 3,341,653 | $11,194,538 | 83.3% |
| PCRX | Sept. 30, 2025 | 457,471 | $10,933,557 | -6.5% |
| BEAM | June 30, 2025 | 526,685 | $10,286,158 | 62.0% |
| MNKD | March 31, 2026 | 1,660,000 | $9,412,200 | 76.9% |
| NUVBWS | March 31, 2026 | 963,333 | $8,631,464 | No longer tracked |
| PRME | Dec. 31, 2025 | 1,543,326 | $8,550,026 | -2.0% |
| DNA | June 30, 2025 | 1,462,328 | $8,335,270 | -32.6% |
| REPL | Sept. 30, 2025 | 850,341 | $7,899,668 | 240.1% |
| BCYC | June 30, 2025 | 910,000 | $7,725,900 | -41.7% |
| KURA | Dec. 31, 2025 | 872,500 | $7,721,625 | 17.2% |
| REPL | June 30, 2026 | 1,000,000 | $7,650,000 | 28.7% |
| ADAPY | Sept. 30, 2025 | 27,404,070 | $6,568,756 | No longer tracked |
| VERV | June 30, 2025 | 1,250,000 | $5,712,500 | No longer tracked |
| DAWN | Sept. 30, 2025 | 862,068 | $5,603,442 | No longer tracked |
| FATE | March 31, 2025 | 3,049,405 | $5,031,518 | 222.8% |
| HLVX | Sept. 30, 2025 | 2,420,243 | $4,816,284 | No longer tracked |
| EOLS | March 31, 2026 | 675,000 | $4,488,750 | 103.9% |
| ALVR | March 31, 2025 | 408,688 | $3,947,926 | No longer tracked |
| PEPG | Dec. 31, 2025 | 800,000 | $3,696,000 | -52.1% |
| PRLD | June 30, 2026 | 947,049 | $3,238,908 | 9.6% |
| IBIO | June 30, 2026 | 1,583,000 | $3,007,700 | -17.1% |
| SLDB | June 30, 2025 | 744,450 | $2,754,465 | 90.7% |
| DSGN | March 31, 2025 | 426,683 | $2,632,634 | 304.4% |
| GBIO | March 31, 2025 | 2,046,867 | $2,169,679 | No longer tracked |
| WHWK | Sept. 30, 2025 | 1,091,417 | $2,040,950 | 153.7% |
| CAMP | March 31, 2026 | 325,000 | $1,992,250 | 1.4% |
| MGNX | Sept. 30, 2025 | 1,602,717 | $1,939,288 | 147.3% |
| KROS | June 30, 2025 | 187,500 | $1,910,625 | -19.3% |
| RLAY | June 30, 2025 | 641,426 | $1,680,536 | 475.0% |
| KLRS | June 30, 2025 | 201,718 | $1,619,796 | 57.3% |
| CMPS | Dec. 31, 2025 | 265,137 | $1,519,235 | 102.8% |
| PRME | June 30, 2025 | 700,000 | $1,393,000 | 37.6% |
| TCRX | June 30, 2025 | 662,833 | $914,710 | -48.2% |
| HOOK | March 31, 2025 | 388,861 | $781,611 | No longer tracked |
| ALGS | June 30, 2025 | 88,569 | $730,694 | -2.8% |
| ARTV | March 31, 2025 | 41,453 | $417,846 | 275.2% |
| UPB | June 30, 2025 | 60,000 | $367,200 | -33.6% |
| GLUE | March 31, 2025 | 21,700 | $150,598 | 226.5% |