EcoR1 Capital, LLC

CIK 0001587114 · Q2 2026

13F Equity AUM

$2.1B

-12.7% QoQ

Positions

+2 QoQ

AUM Rank

#1,503

Top 17%

Skill Alpha (FF)

+0.4%/yr^ns

No Clear Edge

Rank #2,406 · Top 29%

vs S&P -7.7%/yr (unadj.)

Quarters Tracked

~11 years

Portfolio Concentration

Top 5: 73.5%Top 10: 88.3%Top 20: 97.3%

ZYME29.2%

ANAB25.9%

AKTIS ONCOLOGY INC7.6%

CGON7.1%

ETON3.8%

CRSP3.7%

ORIC3.5%

FIRST TRACKS BIOTHERAPEUTICS3.1%

GLPG2.4%

NGNE1.9%

Others (21)11.8%

HHI (Herfindahl-Hirschman Index) measures portfolio concentration. Low (<1500) = diversified, Moderate (1500-2500), High (>2500) = concentrated bets.

Sector Allocation

Healthcare88.0%

Unclassified12.0%

Portfolio weight by GICS sector based on latest 13F filing. Sectors below 2% are grouped as “Other.”

Position Sizing

Positions: 31Median: 0.97%Avg: 3.23%

0–0.5%

11(2.6%)

0.5–1%

5(3.6%)

1–3%

7(9.9%)

3–5%

4(14.2%)

5%+

4(69.7%)

Count of positions per weight bucket — (%) = combined portfolio weight

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Portfolio Overlap

Shared: 0Unique: 31vs 20 funds

0%Low

Fund positions

Consensus CUSIPs

Jaccard similarity of this fund’s portfolio vs the consensus of top 20 funds by AUM. Low (<15%) = contrarian, Moderate (15-40%), High (>40%) = follows the crowd.

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Position Changes This Quarter

New9Increased3Decreased4Exited7

New Positions

FIRST TRACKS BIOTHER…3.1%

+3.2M

FULC1.2%

+6.5M

LEGN1.1%

+800K

AURA0.6%

+1.7M

ODYSSEY THERAPEUTICS…0.5%

+556K

PHVS0.4%

+235K

NRIX0.3%

+270K

ELOXX PHARMACEUTICAL…0.3%

+400K

AARD0.1%

+411K

Increased

ATRA0.9%

+1.5M(+1458%)

CGON7.1%

+954K(+87%)

STOK1.2%

+635K(+635%)

Decreased

MREO0.0%

-12,368,855(-93%)

RLAY0.6%

-1,206,814(-63%)

ERAS0.3%

-570,000(-63%)

MBX1.0%

-388,500(-50%)

Exited

-1,706,469

-6,410,800

-4,288,120

-2,183,000

-1,000,000

-947,049

-1,583,000

Quarter-over-quarter changes compared to prior 13F filing. New = first appearance; Exited = no longer held.

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Holdings

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