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Latest EcoR1 Capital, LLC Stock Portfolio

$2.36Billion | No. of Holdings #29

EcoR1 Capital, LLC Performance

2026 Q1+4.35%
YTD+4.35%
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 2026-05-15, the fund reported it's updated stock portfolio. In the 13F Holdings report, EcoR1 Capital, LLC reported an equity portfolio of $2.4 Billions as of 31 Mar, 2026. <br><br> The top stock holdings of EcoR1 Capital, LLC are ZYME, ANAB, JAZZ. The fund has invested 24.4% of it's portfolio in ZYMEWORKS INC and 18.6% of portfolio in ANAPTYSBIO INC. <br><br> The fund managers got completely rid off IMMUNOME INC (IMNM), STRUCTURE THERAPEUTICS INC and VAXCYTE INC (PCVX) stocks. They significantly reduced their stock positions in ATARA BIOTHERAPEUTICS INC (ATRA), MBX BIOSCIENCES INC and XENCOR INC (XNCR). EcoR1 Capital, LLC opened new stock positions in AKTIS ONCOLOGY INC, RELAY THERAPEUTICS INC (RLAY) and ERASCA INC (ERAS). The fund showed a lot of confidence in some stocks as they added substantially to CENTESSA PHARMACEUTICALS PLC (CNTA), MEREO BIOPHARMA GROUP PLC (MREO) and CG ONCOLOGY INC.
EcoR1 Capital, LLC Equity Portfolio Value
Last Reported on: 15 May, 2026
$2.36Billion
  as of May 15, 2026

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

Our best estimate is that EcoR1 Capital, LLC made a return of 4.35% in the last quarter. In trailing 12 months, it's portfolio return was 90.05%.
  • Performance
  • S&P 500

New Buys

Ticker$ Bought
aktis oncology inc86,309,800
relay therapeutics inc18,952,400
erasca inc14,562,000
eikon therapeutics inc7,750,970
replimune group inc7,650,000
zura bio ltd7,019,300
phathom pharmaceuticals inc6,943,750
stoke therapeutics inc3,256,000
New stocks bought by EcoR1 Capital, LLC

Additions

Ticker% Inc.
centessa pharmaceuticals plc92.62
mereo biopharma group plc70.16
cg oncology inc42.75
eton pharmaceuticals inc6.96
Additions to existing portfolio by EcoR1 Capital, LLC

Reductions

Ticker% Reduced
atara biotherapeutics inc-82.62
mbx biosciences inc-63.41
xencor inc-32.85
ibio inc-28.95
EcoR1 Capital, LLC reduced stake in above stock

Sold off

Ticker$ Sold
voyager therapeutics inc-15,731,200
immunome inc-61,338,100
aquestive therapeutics inc-16,957,500
mannkind corp-9,412,200
nuvation bio inc-8,631,460
evolus inc-4,488,750
vaxcyte inc-20,763,000
structure therapeutics inc-23,256,100
EcoR1 Capital, LLC got rid off the above stocks

Sector Distribution

EcoR1 Capital, LLC has about 61.7% of it's holdings in Healthcare sector.

  • Healthcare
  • Others
Sector%
Healthcare61.7
Others38.3

Market Cap. Distribution

EcoR1 Capital, LLC has about 13.8% of it's portfolio invested in the large-cap and mega-cap stocks.

  • UNALLOCATED
  • SMALL-CAP
  • MID-CAP
  • LARGE-CAP
Category%
UNALLOCATED38.3
SMALL-CAP27.3
MID-CAP20.3
LARGE-CAP13.8

Stocks belong to which Index?

About 57% of the stocks held by EcoR1 Capital, LLC either belong to S&P 500 or RUSSELL 2000 index.

  • RUSSELL 2000
  • Others
Index%
RUSSELL 200057
Others43
Top 5 Winners (%)%
ORIC
oric pharmaceuticals inc
54.9 %
cg oncology inc
49.0 %
ETON
eton pharmaceuticals inc
43.8 %
CNTA
centessa pharmaceuticals plc
39.1 %
SRZN
surrozen inc
28.9 %
Top 5 Winners ($)$
CNTA
centessa pharmaceuticals plc
67.0 M
ANAB
anaptysbio inc
55.0 M
JAZZ
jazz pharmaceuticals plc
32.5 M
ORIC
oric pharmaceuticals inc
30.2 M
cg oncology inc
24.5 M
Top 5 Losers (%)%
zenas biopharma inc
-46.2 %
ATRA
atara biotherapeutics inc
-43.3 %
bridgebio oncology therapeut
-28.5 %
CRNX
crinetics pharmaceuticals in
-22.0 %
XNCR
xencor inc
-17.7 %
Top 5 Losers ($)$
CRNX
crinetics pharmaceuticals in
-43.9 M
ZYME
zymeworks inc
-29.6 M
zenas biopharma inc
-13.2 M
bridgebio oncology therapeut
-10.1 M
XNCR
xencor inc
-8.8 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 29 stocks in it's portfolio. About 88.9% of the portfolio is in top 10 stocks. CRNX proved to be the most loss making stock for the portfolio. CNTA was the most profitable stock for EcoR1 Capital, LLC last quarter.

$2.34BTotal Value
38.00Positions
15 May, 2026Last Reported
Current holdings of Current Stock Holdings of EcoR1 Capital, LLC, last reported on 15 May, 2026. Select a row with a linked ticker to view its historical trend.
ExpandHoldingsorted ascending% PortfolioShares Held$ Value% Change
GLPG
Galapagos Nv

Galapagos Nv

GLPG
EcoR1 Capital, LLC's holding in Galapagos Nv over time
2.12%1,667,120
$50.01M
2.12%
unchanged 0 percentunchanged
MREO
Mereo Biopharma Group Plc

Mereo Biopharma Group Plc

MREO
EcoR1 Capital, LLC's holding in Mereo Biopharma Group Plc over time
0.19%13,368,900
$4.41M
0.19%
increased 70.16 percentadded