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EcoR1 Capital Portfolio holdings

AUM $2.06B
1-Year Est. Return 215.32%
This Fund
S&P 500
This Quarter Est. Return
+12.48%
1 Year Est. Return
+215.32%
3 Year Est. Return
+310.3%
5 Year Est. Return
+497.45%
10 Year Est. Return
+14,692.23%
AUM
$2.36B
AUM Growth
+$152M
Cap. Flow
+$32.9M
Cap. Flow %
1.4%
Top 10 Hldgs %
88.9%
Holding
41
New
11
Increased
4
Reduced
4
Closed
11
Avg Time Held Equity + Options
6.7 quarters
Top 10 Avg Time Held Equity + Options
5.1 quarters
Top 20 Avg Time Held Equity + Options
6 quarters
Avg Time Held Equity only
6.9 quarters
Top 10 Avg Time Held Equity only
5.1 quarters
Top 20 Avg Time Held Equity only
6 quarters

Top Buys

Rank Stock Value
1
AKTS icon
Aktis Oncology
AKTS
+$93.7M
2
CNTA
Centessa Pharmaceuticals
CNTA
+$73.8M
3
CGON icon
CG Oncology
CGON
+$18.7M
4
RLAY icon
Relay Therapeutics
RLAY
+$17M
5
ERAS icon
Erasca
ERAS
+$10.6M

Top Sells

Rank Stock Value
1
IMNM icon
Immunome
IMNM
+$61.3M
2
MBX icon
MBX Biosciences
MBX
+$45.8M
3
GPCR icon
Structure Therapeutics
GPCR
+$23.3M
4
PCVX icon
Vaxcyte
PCVX
+$20.8M
5
AQST icon
Aquestive Therapeutics
AQST
+$17M

Sector Composition

Rank Sector Weight
1 Healthcare 99.22%
2 Miscellaneous 0.7%
3 Financials 0.09%
Name Market Value Portfolio Weight Shares or Principal Change
in Stake 		Capital Flow Held Since
ZYME icon
1
Zymeworks
ZYME
$1.8B
$575M 24.41%
22,970,388
– –
2022 Q4
13 quarters
ANAB icon
2
AnaptysBio
ANAB
$1.36B
$437M 18.55%
7,880,094
– –
2019 Q4
25 quarters
JAZZ icon
3
Jazz Pharmaceuticals
JAZZ
$13.7B
$323M 13.69%
1,706,469
– –
2023 Q2
11 quarters
CNTA
4
DELISTED
Centessa Pharmaceuticals
CNTA
$238M 10.11%
6,000,000
+2,885,000
+93% +$73.8M
2025 Q3
2 quarters
CRNX icon
5
DELISTED
Crinetics Pharmaceuticals
CRNX
$156M 6.61%
4,288,120
– –
2021 Q4
17 quarters
AKTS icon
6
Aktis Oncology
AKTS
$926M
$86.3M 3.66%
+4,824,469
New +$93.7M
2026 Q1
0 quarters
ORIC icon
7
Oric Pharmaceuticals
ORIC
$1.17B
$85.2M 3.62%
6,728,116
– –
2020 Q2
23 quarters
CGON icon
8
CG Oncology
CGON
$5.53B
$74.6M 3.17%
1,102,000
+330,000
+43% +$18.7M
2025 Q4
1 quarter
CRSP icon
9
CRISPR Therapeutics
CRSP
$4.84B
$66.1M 2.8%
1,389,276
– –
2024 Q1
8 quarters
ETON icon
10
Eton Pharmaceutcials
ETON
$1.52B
$53.6M 2.27%
2,171,938
+141,394
+7% +$2.47M
2024 Q3
6 quarters
LKFT icon
11
Lakefront Biotherapeutics American Depositary Shares
LKFT
$1.9B
$50M 2.12%
1,667,119
– –
2021 Q3
18 quarters
XNCR icon
12
Xencor
XNCR
$1.75B
$26.3M 1.12%
2,183,000
-1,068,112
-33% -$13.3M
2018 Q4
29 quarters
NGNE icon
13
Neurogene
NGNE
$431M
$25.6M 1.09%
1,271,342
– –
2023 Q4
9 quarters
BBOT icon
14
BridgeBio Oncology
BBOT
$237M
$25.3M 1.07%
2,823,126
– –
2025 Q3
2 quarters
MBX icon
15
MBX Biosciences
MBX
$2.36B
$23.2M 0.98%
777,000
-1,346,604
-63% -$45.8M
2024 Q3
6 quarters
RLAY icon
16
Relay Therapeutics
RLAY
$3.8B
$19M 0.8%
+1,904,762
New +$17M
2026 Q1
0 quarters
CNTA
17
CALL
DELISTED
Centessa Pharmaceuticals
CNTA
$16.3M 0.69%
+410,800
New +$10.5M
2026 Q1
0 quarters
ZBIO icon
18
Zenas BioPharma
ZBIO
$1.64B
$15.4M 0.66%
789,500
– –
2025 Q4
1 quarter
ERAS icon
19
Erasca
ERAS
$5.17B
$14.6M 0.62%
+900,000
New +$10.6M
2026 Q1
0 quarters
EIKN icon
20
Eikon Therapeutics
EIKN
$364M
$7.75M 0.33%
+732,606
New +$9.79M
2026 Q1
0 quarters
REPL icon
21
Replimune Group
REPL
$1.14B
$7.65M 0.32%
+1,000,000
New +$7.64M
2026 Q1
0 quarters
ZURA icon
22
Zura Bio
ZURA
$405M
$7.02M 0.3%
+1,179,715
New +$7.13M
2026 Q1
0 quarters
PHAT icon
23
Phathom Pharmaceuticals
PHAT
$566M
$6.94M 0.29%
+625,000
New +$7.89M
2026 Q1
0 quarters
MREO icon
24
Mereo BioPharma
MREO
$51.1M
$4.41M 0.19%
13,368,855
+5,512,389
+70% +$2.37M
2025 Q4
1 quarter
STOK icon
25
Stoke Therapeutics
STOK
$1.45B
$3.26M 0.14%
+100,000
New +$3.28M
2026 Q1
0 quarters
1
2

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EcoR1 Capital's Q1 2026 Portfolio in Review

As of Q1 2026, EcoR1 Capital held 41 positions worth $2.36B, up 6.9% from $2.2B the previous quarter. Its ten largest holdings account for 89% of the portfolio.

EcoR1 Capital's Q1 2026 filing shows 11 new, 4 increased, 4 reduced and 11 closed positions. Its largest new stake was Aktis Oncology: 4,824,469 shares worth $86.3M. The largest sale was Immunome, an estimated $61.3M.

By sector, the portfolio is most concentrated in Healthcare at 99% of assets, up from 99% a quarter earlier, followed by Miscellaneous and Financials.

  • EcoR1 Capital's largest Q1 2026 buy was Aktis Oncology: 4,824,469 shares worth $86.3M.
  • EcoR1 Capital added most to Centessa Pharmaceuticals in Q1 2026, an estimated $73.8M increase.
  • EcoR1 Capital's biggest Q1 2026 reduction was MBX Biosciences, cutting an estimated $45.8M.
  • EcoR1 Capital fully exited Immunome in Q1 2026, selling an estimated $61.3M.
  • EcoR1 Capital's ten largest holdings make up 89% of its $2.36B portfolio in Q1 2026.
  • EcoR1 Capital opened 11 new positions and closed 11 in Q1 2026.
  • EcoR1 Capital's portfolio value rose 6.9% quarter-over-quarter to $2.36B.

Based on EcoR1 Capital's 13F filing for Q1 2026, filed 15 May 2026.