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Latest EcoR1 Capital, LLC Stock Portfolio

$2.06Billion | No. of Holdings #31

EcoR1 Capital, LLC Performance

2026 Q2+26.23%
YTD+31.72%
2025+35.99%

About EcoR1 Capital, LLC and 13F Hedge Fund Stock Holdings

EcoR1 Capital, LLC is a hedge fund based in San Francisco, CA. On 2026-08-14, the fund reported it's updated stock portfolio. In the 13F Holdings report, EcoR1 Capital, LLC reported an equity portfolio of $2.1 Billions as of 30 Jun, 2026. <br><br> The top stock holdings of EcoR1 Capital, LLC are ZYME, ANAB, . The fund has invested 29.2% of it's portfolio in ZYMEWORKS INC and 25.9% of portfolio in ANAPTYSBIO INC. <br><br> The fund managers got completely rid off JAZZ PHARMACEUTICALS PLC (JAZZ), CENTESSA PHARMACEUTICALS PLC (CNTA) and CRINETICS PHARMACEUTICALS IN (CRNX) stocks. They significantly reduced their stock positions in MEREO BIOPHARMA GROUP PLC (MREO), RELAY THERAPEUTICS INC (RLAY) and ERASCA INC (ERAS). EcoR1 Capital, LLC opened new stock positions in FIRST TRACKS BIOTHERAPEUTICS, FULCRUM THERAPEUTICS INC (FULC) and LEGEND BIOTECH CORP (LEGN). The fund showed a lot of confidence in some stocks as they added substantially to ATARA BIOTHERAPEUTICS INC (ATRA), STOKE THERAPEUTICS INC (STOK) and CG ONCOLOGY INC.
EcoR1 Capital, LLC Equity Portfolio Value
Last Reported on: 14 Aug, 2026
$2.06Billion
  as of Aug 14, 2026

EcoR1 Capital, LLC Annual Return Estimates Vs S&P 500

Our best estimate is that EcoR1 Capital, LLC made a return of 26.23% in the last quarter. In trailing 12 months, it's portfolio return was 136.56%.
  • Performance
  • S&P 500

New Buys

Ticker$ Bought
first tracks biotherapeutics63,871,300
fulcrum therapeutics inc23,972,500
legend biotech corp23,104,000
aura biosciences inc11,833,300
odyssey therapeutics inc10,394,400
pharvaris n v8,126,300
nurix therapeutics inc6,550,200
eloxx pharmaceuticals inc5,552,000
New stocks bought by EcoR1 Capital, LLC

Additions

Ticker% Inc.
atara biotherapeutics inc1,458
stoke therapeutics inc635
cg oncology inc35.6
Additions to existing portfolio by EcoR1 Capital, LLC

Reductions

Ticker% Reduced
mereo biopharma group plc-92.52
relay therapeutics inc-63.36
erasca inc-63.33
mbx biosciences inc-50.00
anaptysbio inc-33.33
EcoR1 Capital, LLC reduced stake in above stock

Sold off

Ticker$ Sold
centessa pharmaceuticals plc-238,320,000
crinetics pharmaceuticals in-155,745,000
xencor inc-26,327,000
jazz pharmaceuticals plc-322,608,000
ibio inc-3,007,700
replimune group inc-7,650,000
prelude therapeutics inc-3,238,910
EcoR1 Capital, LLC got rid off the above stocks

Sector Distribution

EcoR1 Capital, LLC has about 56.9% of it's holdings in Others sector.

  • Others
  • Healthcare
Sector%
Others56.9
Healthcare43.1

Market Cap. Distribution

EcoR1 Capital, LLC has about 0% of it's portfolio invested in the large-cap and mega-cap stocks.

  • UNALLOCATED
  • SMALL-CAP
  • MID-CAP
  • MICRO-CAP
Category%
UNALLOCATED56.9
SMALL-CAP36
MID-CAP5
MICRO-CAP2.1

Stocks belong to which Index?

About 64% of the stocks held by EcoR1 Capital, LLC either belong to S&P 500 or RUSSELL 2000 index.

  • RUSSELL 2000
  • Others
Index%
RUSSELL 200064
Others36
Top 5 Winners (%)%
aktis oncology inc
80.2 %
ANAB
anaptysbio inc
68.8 %
mbx biosciences inc
63.7 %
RLAY
relay therapeutics inc
60.1 %
neurogene inc
56.0 %
Top 5 Winners ($)$
ANAB
anaptysbio inc
300.7 M
aktis oncology inc
69.2 M
ZYME
zymeworks inc
25.3 M
ETON
eton pharmaceuticals inc
25.0 M
mbx biosciences inc
14.8 M
Top 5 Losers (%)%
bridgebio oncology therapeut
-14.9 %
ORIC
oric pharmaceuticals inc
-14.5 %
SRZN
surrozen inc
-10.9 %
PHAT
phathom pharmaceuticals inc
-2.3 %
MREO
mereo biopharma group plc
-2.0 %
Top 5 Losers ($)$
ORIC
oric pharmaceuticals inc
-12.4 M
bridgebio oncology therapeut
-3.8 M
PHAT
phathom pharmaceuticals inc
-0.2 M
MREO
mereo biopharma group plc
-0.1 M
zura bio ltd
-0.1 M

EcoR1 Capital, LLC Holdings Map

This heatmap illustrates the top 50 positions within the fund's portfolio.

Current Stock Holdings of EcoR1 Capital, LLC

EcoR1 Capital, LLC has 31 stocks in it's portfolio. About 86.3% of the portfolio is in top 10 stocks. ORIC proved to be the most loss making stock for the portfolio. ANAB was the most profitable stock for EcoR1 Capital, LLC last quarter.

$2.02BTotal Value
38.00Positions
14 Aug, 2026Last Reported
Current holdings of Current Stock Holdings of EcoR1 Capital, LLC, last reported on 14 Aug, 2026. Select a row with a linked ticker to view its historical trend.
ExpandHoldingsorted ascending% PortfolioShares Held$ Value% Change
ELOX
Eloxx Pharmaceuticals Inc

Eloxx Pharmaceuticals Inc

ELOX
EcoR1 Capital, LLC's holding in Eloxx Pharmaceuticals Inc over time
0.27%400,000
$5.55M
0.27%
new position
GLPG
Lakefront Biotherapeutics Nv

Lakefront Biotherapeutics Nv

GLPG
EcoR1 Capital, LLC's holding in Lakefront Biotherapeutics Nv over time
2.43%1,667,120
$49.98M
2.43%
unchanged 0 percentunchanged
LEGN
Legend Biotech Corp

Legend Biotech Corp

LEGN
EcoR1 Capital, LLC's holding in Legend Biotech Corp over time
1.12%800,000
$23.10M
1.12%
new position
MREO
Mereo Biopharma Group Plc

Mereo Biopharma Group Plc

MREO
EcoR1 Capital, LLC's holding in Mereo Biopharma Group Plc over time
0.01%1,000,000
$317.7K
0.01%
decreased 92.52 percentreduced
PHVS
Pharvaris N V

Pharvaris N V

PHVS
EcoR1 Capital, LLC's holding in Pharvaris N V over time
0.4%235,000
$8.13M
0.4%
new position