EcoR1 Capital, LLC

Q1 2026 13F-HR Holdings

Location
San Francisco, CA
Holdings as of
3/31/2026
Date filed
5/15/2026
Form type
13F-HR
Num holdings
30
Total value ($000)
$2,356,319
Net value change ($000)
+152,310 (6.9%)
New positions
10
Sold out positions
8
Turnover %
13.3%
Sector allocation + QoQ delta (equities-only)
Prev filing: 2/17/2026 Next filing: — SEC filing

Snapshot: Change Analysis

Compared to Q4 2025
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)
CNTA 160,414 205.9%
AKTS 86,310 NEW
ANAB 55,003 14.4%
CGON 42,530 132.7%
JAZZ 32,508 11.2%
ORIC 30,209 54.9%
ETON 19,267 56.1%
RLAY 18,952 NEW
ERAS 14,562 NEW
EIKN 7,751 NEW
Top Reduces (Value $000, Stocks/ETFs)
IMNM -61,338 -100.0%
CRNX -43,867 -22.0%
MBX -43,785 -65.4%
ZYME -29,631 -4.9%
XNCR -23,448 -47.1%
GPCR -23,256 -100.0%
PCVX -20,763 -100.0%
AQST -16,958 -100.0%
VYGR -15,731 -100.0%
ZBIO -13,232 -46.2%
Instrument mix + QoQ Δ (ex-options)
Derivatives reported exposure ($000): 16,317 (0.7% 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