13F
中
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EcoR1 Capital, LLC

13F equity value
$2.3B
Positions
29
Top 10 concentration
89.5%
Quarters / total new picks
30 / 118
13F equity value over time
$0M$2B$4B2017201820192020202120222023202420252026

"13F equity value" = market value of this filer's US-listed long equity positions only. It excludes cash, bonds, non-US and short positions, so it understates a fund's true assets under management — often by a lot.

Negative Verdict

13F holdings are disclosed ~45 days after quarter-end, and they never reveal when within the quarter a fund actually bought. So any 13F-based summary is structurally late and blurred — this applies to every fund, including this one.

We backtested copying it. Buying this fund's new positions the day each filing went public, over 30 quarters, returned +1.1% per quarter versus +1.9% from simply owning every 13F stock — it beat that baseline in only 40.0% of quarters (excess t = -2.88). Copying it would have systematically underperformed the simplest possible strategy.

Avg 2Q excess
-11.7%
t-stat
-2.88
Quarterly win rate
40%
Annualized excess
-12.4%
$1 → follow vs universe
$0.62 vs $1.58
Cumulative return: $1 invested in new picks vs universe
1.00 20180331: universe 1.04120180630: universe 0.95920180930: universe 1.00320181231: universe 0.99220190331: universe 0.97520190930: universe 1.04820191231: universe 0.84620200331: universe 1.02020200630: universe 1.12620201231: universe 1.17820210331: universe 1.18820210630: universe 1.28320210930: universe 1.15220211231: universe 0.98020220331: universe 1.05220220630: universe 0.97520220930: universe 1.04720221231: universe 0.97320230331: universe 1.02520230630: universe 0.98820230930: universe 1.12220231231: universe 1.17220240331: universe 1.19820240630: universe 1.30720240930: universe 1.29620241231: universe 1.20920250331: universe 1.31820250630: universe 1.36020250930: universe 1.52920251231: universe 1.582 20180331: follow 1.07920180630: follow 0.65820180930: follow 0.64820181231: follow 0.61320190331: follow 0.59920190930: follow 0.75320191231: follow 0.80820200331: follow 0.82920200630: follow 0.92320201231: follow 0.78920210331: follow 1.02220210630: follow 1.53820210930: follow 1.23720211231: follow 1.11320220331: follow 1.42520220630: follow 1.17420220930: follow 0.99220221231: follow 0.99220230331: follow 0.66620230630: follow 0.41820230930: follow 0.63920231231: follow 0.67320240331: follow 0.66720240630: follow 0.69320240930: follow 0.67520241231: follow 0.46920250331: follow 0.68620250630: follow 0.65620250930: follow 0.71320251231: follow 0.623 0.38 1.05 1.71 20182019202020212022202320242025 Follow Universe

Quarterly compounding, invested quarters only · entry 47 days after quarter-end (when 13F data becomes public)

Listed as facts. See the verdict above before treating this as signal.

Top 20 holdings of 29 · 2026 Q1

Ticker Value Weight QoQ
ZYME $575M
24.6%
HOLD
ANAB $437M
18.7%
HOLD
JAZZ $323M
13.8%
HOLD
CNTA $238M
10.2%
ADD
CRNX $156M
6.7%
HOLD
AKTS $86M
3.7%
NEW
ORIC $85M
3.6%
HOLD
CGON $75M
3.2%
ADD
CRSP $66M
2.8%
HOLD
ETON $54M
2.3%
ADD
LKFT $50M
2.1%
HOLD
XNCR $26M
1.1%
TRIM
NGNE $26M
1.1%
HOLD
BBOT $25M
1.1%
HOLD
MBX $23M
1.0%
TRIM
RLAY $19M
0.8%
NEW
ZBIO $15M
0.7%
HOLD
ERAS $15M
0.6%
NEW
EIKN $8M
0.3%
NEW
REPL $8M
0.3%
NEW

QoQ vs previous quarter's share count · NEW = new position · ADD/TRIM = ±2% shares · HOLD = unchanged.

Listed as facts. See the verdict above before treating this as signal.

New positions in 2026 Q1

ERASPHATREPLRLAYSTOKZURA

Method & Limitations

Method: a "new position" = held this quarter, absent last quarter (options excluded; stocks with <50 prior holders excluded to filter spin-off artifacts). Entry 47 days after quarter-end — the first day the public could act on the filing. Benchmark = equal-weighted universe of all 13F-held stocks. Limitations: quarterly snapshots can't see intra-quarter trades; survivorship bias — funds that shut down are absent, which flatters the sample. Statistics, not advice.