2026 Q2 Portfolio Activity
In 2026 Q2, EcoR1 Capital, LLC maintained a portfolio of 41 distinct positions. The most significant new addition was FULCRUM THERAPEUTICS INC, now representing 1.17% of the total fund value. They heavily accumulated shares in AKTIS ONCOLOGY INC, increasing the position by 2312.2%. Conversely, EcoR1 Capital, LLC completely exited their position in JAZZ PHARMACEUTICALS PLC.
Position History
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Total Positions
41
Quarter
2026 Q2
Top Holding
ZYME (29.2%)
Top 10 Concentration
86.3%
Turnover Rate
23.4%
Sector HHI
0.18
Items per page:
Showing 1-41 of 41
EcoR1 Capital, LLC Full Holdings List — 2026 Q2
| Stock | History | Sector / Type | Port % | Prev % | Rank / Prev | Conviction | Change | % Change | Influence | Shares | Mkt Value | Avg Cost | Price Held | 1st Owned | Source | Source Date | Date Reported | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
ZYME
ZYMEWORKS INC
|
Healthcare | 29.19% | 24.41% |
#1
Prev: #1
|
7.0 |
—
|
no change | no change |
P
S
|
22,970,388 | $600,445,942 |
$10.13
+161.7%
|
2022 Q4 | 13F Filing | 2026-06-30 | 2026-08-14 | ||
|
ANAB
ANAPTYSBIO INC
|
Healthcare | 25.86% | 18.55% |
#2
Prev: #2
|
6.5 |
—
|
no change | no change |
P
S
|
7,880,094 | $531,906,345 |
$13.09
+289.7%
|
2019 Q4 | 13F Filing | 2026-06-30 | 2026-08-14 | ||
|
N/A
AKTIS ONCOLOGY ...
|
|
Unknown | 7.56% | 3.66% |
#3
3
Prev: #6
|
5.0 |
—
|
no change | no change |
P
S
|
4,824,469 | $155,492,636 | — | 13F Filing | 2026-06-30 | 2026-08-14 | ||
|
CGON
CG ONCOLOGY INC
|
Healthcare | 5.16% | 3.17% |
#4
4
Prev: #8
|
5.1 |
—
|
392,300 | 35.6% |
P
S
|
1,494,300 | $106,170,015 | 2025 Q4 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
ETON
ETON PHARMACEUT...
|
Healthcare | 3.82% | 2.27% |
#5
5
Prev: #10
|
3.0 |
—
|
no change | no change |
P
S
|
2,171,938 | $78,624,156 | 2024 Q3 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
CRSP
CRISPR THERAPEU...
|
Healthcare | 3.68% | 2.80% |
#6
3
Prev: #9
|
2.5 |
—
|
no change | no change |
P
S
|
1,389,276 | $75,771,113 | 2018 Q3 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
ORIC
ORIC PHARMACEUT...
|
Healthcare | 3.54% | 3.62% |
#7
Prev: #7
|
2.4 |
—
|
no change | no change |
P
S
|
6,728,116 | $72,865,496 | 2020 Q2 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
N/A
FIRST TRACKS BI...
|
|
Unknown | 3.11% | — |
#8
Prev: #—
|
4.7 |
—
|
3,174,519 | — |
NEW
|
3,174,519 | $63,871,322 | — | 13F Filing | 2026-06-30 | 2026-08-14 | ||
|
GLPG
LAKEFRONT BIOTH...
|
Healthcare | 2.43% | 2.12% |
#9
2
Prev: #11
|
2.0 |
—
|
no change | no change |
P
S
|
1,667,119 | $49,980,228 | 2015 Q4 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
NGNE
NEUROGENE INC
|
Healthcare | 1.94% | 1.09% |
#10
3
Prev: #13
|
1.8 |
—
|
no change | no change |
P
S
|
1,271,342 | $39,983,706 | 2023 Q4 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
CGON
CALL
CG ONCOLOGY INC
|
CALL Option | 1.94% | — |
#11
Prev: #—
|
4.3 |
—
|
561,500 | — |
NEW
|
561,500 | $39,894,575 | 2025 Q4 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
STOK
STOKE THERAPEUT...
|
Healthcare | 1.17% | 0.14% |
#12
13
Prev: #25
|
3.5 |
—
|
635,000 | 635.0% |
P
S
|
735,000 | $24,049,200 | 2026 Q1 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
FULC
FULCRUM THERAPE...
|
Healthcare | 1.17% | — |
#13
Prev: #—
|
4.0 |
—
|
6,549,866 | — |
NEW
|
6,549,866 | $23,972,510 | 2020 Q2 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
LEGN
LEGEND BIOTECH ...
|
Healthcare | 1.12% | — |
#14
Prev: #—
|
3.9 |
—
|
800,000 | — |
NEW
|
800,000 | $23,104,000 | 2021 Q4 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
BBOT
BRIDGEBIO ONCOL...
|
Healthcare | 1.05% | 1.07% |
#15
1
Prev: #14
|
1.4 |
—
|
no change | no change |
P
S
|
2,823,126 | $21,512,220 | 2025 Q3 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
MBX
MBX BIOSCIENCES...
|
Healthcare | 1.04% | 0.98% |
#16
1
Prev: #15
|
0.4 |
—
|
-388,500 | -50.0% |
P
S
|
388,500 | $21,445,200 | 2024 Q3 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
ZBIO
ZENAS BIOPHARMA...
|
Healthcare | 0.97% | 0.66% |
#17
1
Prev: #18
|
1.4 |
—
|
no change | no change |
P
S
|
789,500 | $20,037,510 | 2025 Q4 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
ATRA
ATARA BIOTHERAP...
|
Healthcare | 0.87% | 0.02% |
#18
11
Prev: #29
|
3.3 |
—
|
1,452,407 | 1458.3% |
P
S
|
1,552,000 | $17,816,960 | 2024 Q2 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
RLAY
RELAY THERAPEUT...
|
Healthcare | 0.63% | 0.80% |
#19
3
Prev: #16
|
0.3 |
—
|
-1,206,814 | -63.4% |
P
S
|
697,948 | $13,058,607 | 2020 Q3 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
AURA
AURA BIOSCIENCE...
|
Healthcare | 0.58% | — |
#20
Prev: #—
|
3.7 |
—
|
1,666,667 | — |
NEW
|
1,666,667 | $11,833,336 | 2026 Q2 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
N/A
ODYSSEY THERAPE...
|
|
Unknown | 0.51% | — |
#21
Prev: #—
|
3.7 |
—
|
555,555 | — |
NEW
|
555,555 | $10,394,434 | — | 13F Filing | 2026-06-30 | 2026-08-14 | ||
|
N/A
EIKON THERAPEUT...
|
|
Unknown | 0.46% | 0.33% |
#22
2
Prev: #20
|
1.2 |
—
|
no change | no change |
P
S
|
732,606 | $9,560,508 | — | 13F Filing | 2026-06-30 | 2026-08-14 | ||
|
PHVS
PHARVARIS N V
|
Healthcare | 0.40% | — |
#23
Prev: #—
|
3.7 |
—
|
235,000 | — |
NEW
|
235,000 | $8,126,300 | 2023 Q4 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
ZURA
ZURA BIO LTD
|
Healthcare | 0.34% | 0.30% |
#24
2
Prev: #22
|
1.1 |
—
|
no change | no change |
P
S
|
1,179,715 | $6,960,319 | 2026 Q1 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
PHAT
PHATHOM PHARMAC...
|
Healthcare | 0.33% | 0.29% |
#25
2
Prev: #23
|
1.1 |
—
|
no change | no change |
P
S
|
625,000 | $6,781,250 | 2023 Q2 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
NRIX
NURIX THERAPEUT...
|
Healthcare | 0.32% | — |
#26
Prev: #—
|
3.6 |
—
|
270,000 | — |
NEW
|
270,000 | $6,550,200 | 2020 Q3 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
ERAS
ERASCA INC
|
Healthcare | 0.29% | 0.62% |
#27
8
Prev: #19
|
0.1 |
—
|
-570,000 | -63.3% |
P
S
|
330,000 | $6,045,600 | 2021 Q3 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
N/A
ELOXX PHARMACEU...
|
|
Unknown | 0.27% | — |
#28
Prev: #—
|
3.6 |
—
|
400,000 | — |
NEW
|
400,000 | $5,552,000 | — | 13F Filing | 2026-06-30 | 2026-08-14 | ||
|
AARD
AARDVARK THERAP...
|
Healthcare | 0.11% | — |
#29
Prev: #—
|
3.5 |
—
|
396,194 | — |
NEW
|
396,194 | $2,282,077 | 2026 Q2 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
N/A
HELIX ACQUISITI...
|
|
Unknown | 0.10% | 0.09% |
#30
2
Prev: #28
|
1.0 |
—
|
no change | no change |
P
S
|
200,000 | $2,128,000 | — | 13F Filing | 2026-06-30 | 2026-08-14 | ||
|
MREO
MEREO BIOPHARMA...
|
Healthcare | 0.02% | 0.19% |
#31
7
Prev: #24
|
0.0 |
—
|
-12,368,855 | -92.5% |
P
S
|
1,000,000 | $317,700 | 2025 Q4 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
SRZNW
SURROZEN INC
|
Unknown | 0.01% | 0.01% |
#32
2
Prev: #30
|
1.0 |
—
|
no change | no change |
P
S
|
4,444 | $115,322 | 2021 Q3 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
AARD
CALL
AARDVARK THERAP...
|
CALL Option | 0.00% | — |
#33
Prev: #—
|
3.5 |
—
|
14,700 | — |
NEW
|
14,700 | $84,672 | 2026 Q2 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
IBIO
IBIO INC
|
Healthcare | 0.00% | 0.13% |
Sold All 😨
(Was: #27) |
0.0 |
—
|
-1,583,000 | -100.0% |
CLOSED
|
— | $— | 2025 Q4 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
PRLD
PRELUDE THERAPE...
|
Healthcare | 0.00% | 0.14% |
Sold All 😨
(Was: #26) |
0.0 |
—
|
-947,049 | -100.0% |
CLOSED
|
— | $— | 2023 Q2 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
REPL
REPLIMUNE GROUP...
|
Healthcare | 0.00% | 0.32% |
Sold All 😨
(Was: #21) |
0.0 |
—
|
-1,000,000 | -100.0% |
CLOSED
|
— | $— | 2024 Q2 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
CNTA
CALL
CENTESSA PHARMA...
|
CALL Option | 0.00% | 0.69% |
Sold All 😨
(Was: #17) |
0.0 |
—
|
-410,800 | -100.0% |
CLOSED
|
— | $— | 2021 Q2 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
XNCR
XENCOR INC
|
Healthcare | 0.00% | 1.12% |
Sold All 😨
(Was: #12) |
0.0 |
—
|
-2,183,000 | -100.0% |
CLOSED
|
— | $— | 2016 Q2 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
CRNX
CRINETICS PHARM...
|
Healthcare | 0.00% | 6.61% |
Sold All 😨
(Was: #5) |
0.0 |
—
|
-4,288,120 | -100.0% |
CLOSED
|
— | $— | 2020 Q1 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
CNTA
CENTESSA PHARMA...
|
Healthcare | 0.00% | 10.11% |
Sold All 😨
(Was: #4) |
0.0 |
—
|
-6,000,000 | -100.0% |
CLOSED
|
— | $— | 2021 Q2 | 13F Filing | 2026-06-30 | 2026-08-14 | |||
|
JAZZ
JAZZ PHARMACEUT...
|
Healthcare | 0.00% | 13.69% |
Sold All 😨
(Was: #3) |
0.0 |
—
|
-1,706,469 | -100.0% |
CLOSED
|
— | $— | 2023 Q2 | 13F Filing | 2026-06-30 | 2026-08-14 |
Showing 1-41 of 41 holdings