EcoR1 Capital, LLC

Q2 2026 13F-HR Holdings

Location
San Francisco, CA
Holdings as of
6/30/2026
Date filed
8/14/2026
Form type
13F-HR
Num holdings
33
Total value ($000)
$2,056,733
Net value change ($000)
-299,586 (-12.7%)
New positions
9
Sold out positions
7
Turnover %
45.3%
Sector allocation + QoQ delta (equities-only)
Prev filing: 5/15/2026 Next filing: — SEC filing

Snapshot: Change Analysis

Compared to Q1 2026
Methodology: sector metrics are equities-only; instrument mix chart is ex-options; options exposure is shown separately. Why this matters.
Top Adds (Value $000, Stocks/ETFs)
ANAB 94,876 21.7%
AKTS 69,183 80.2%
FIRST TRACKS BIOTHERAPEUTICS 63,871 NEW
CGON 31,587 42.4%
ZYME 25,267 4.4%
ETON 25,021 46.7%
FULC 23,973 NEW
LEGN 23,104 NEW
STOK 20,793 638.6%
ATRA 17,346 3682.8%
Top Reduces (Value $000, Stocks/ETFs)
JAZZ -322,608 -100.0%
CNTA -238,320 -100.0%
CRNX -155,745 -100.0%
XNCR -26,327 -100.0%
ORIC -12,380 -14.5%
ERAS -8,516 -58.5%
REPL -7,650 -100.0%
RLAY -5,893 -31.1%
MREO -4,094 -92.8%
BBOT -3,755 -14.9%
Instrument mix + QoQ Δ (ex-options)
Derivatives reported exposure ($000): 39,980 (1.9% of total reported value)
How this table is calculated: SEC VALUE ($000) is used as reported. For derivatives (PUT/CALL/WARRANT/RIGHT), SEC value represents reported underlying exposure, not premium cash paid/received. Column % is bucket-based: non-options share is calculated inside non-option total, options share is calculated inside options total. Details.
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Instrument:
Issuer Name Ticker Sector Industry Class History Value ($000) % Shares Shares Δ Shares Δ% Value Δ ($000) Value Δ% Principal Option Type