EcoR1 Capital, LLC

Sector-focusedMomentum followerQuality / disciplined sizing

Total reported value

$2.4B

Reporting period: 2026-03-31 · Number of holdings: 30

EcoR1 Capital, LLC disclosed 30 holdings in its latest 13F filing for the period ending 2026-03-31, with total reported value of $2.4B and a quarterly turnover rate of 37.4%.

Personality snowflake

Concentration: 53.93
Portfolio Stability: 37.44
Momentum/Contrarian: 100
Sector conviction: 100
Diversification: 58
Sizing Uniformity: 82.64

Recent moves

Add 260
+105.8%　$176.7M
Trim ZYME
0.0%　-$29.6M
Trim CRNX
0.0%　-$43.9M
Trim MBX
-63.4%　-$43.8M
Add ANAB
0.0%　$55.0M
Trim XNCR
-34.2%　-$24.5M

Holdings Map

New buyAddUnchangedTrim

Top 10 holdings by weight

Full holdings list this quarter

Showing top 29 holdings (of 30 total)

#	Ticker	Issuer	Asset Subclass	Weight	Weight Change	Shares Change
1	ZYME	Zymeworks INC	Stock-Other	24.41%	-3.03%	—
2	ANAB	Anaptysbio INC	Stock-Other	18.55%	+1.22%	—
3	JAZZ	Jazz Pharmaceuticals plc	Stock-Healthcare	13.69%	+0.53%	—
4	260	Centessa Pharmaceuticals-adr	Stock-Other	10.81%	+7.28%	+105.80%
5	CRNX	Crinetics Pharmaceuticals In	Stock-Other	6.61%	-2.45%	—
6	AKTS	Aktis Oncology INC	Stock-Other	3.66%	+3.66%	NEW
7	ORIC	Oric Pharmaceuticals INC	Stock-Other	3.62%	+1.12%	—
8	CGON	Cg Oncology INC	Stock-Other	3.17%	+1.16%	+3.49%
9	CRSP	CRISPR Therapeutics AG	Stock-Healthcare	2.80%	-0.51%	—
10	ETON	Eton Pharmaceuticals INC	Stock-Other	2.27%	+0.71%	+6.96%
11	LKFT	Lakefront Biotherapeutic-adr	Stock-Other	2.12%	-0.35%	—
12	XNCR	Xencor INC	Stock-Other	1.12%	-1.19%	-34.22%
13	NGNE	Neurogene INC	Stock-Other	1.09%	-0.10%	—
14	BBOT	Bridgebio Oncology Therapeut	Stock-Other	1.07%	-0.53%	—
15	MBX	Mbx Biosciences INC	Stock-Other	0.98%	-2.06%	-63.41%
16	RLAY	Relay Therapeutics INC	Stock-Other	0.80%	+0.80%	NEW
17	ZBIO	Zenas Biopharma INC	Stock-Other	0.66%	-0.64%	—
18	ERAS	Erasca INC	Stock-Other	0.62%	+0.62%	NEW
19	EIKN	Eikon Therapeutics INC	Stock-Other	0.33%	+0.33%	NEW
20	REPL	Replimune Group INC	Stock-Other	0.32%	+0.32%	NEW
21	✓	Zura Bio LTD	Stock-Other	0.30%	+0.30%	NEW
22	PHAT	Phathom Pharmaceuticals INC	Stock-Other	0.29%	+0.29%	NEW
23	MREO	Mereo Biopharma Group Pl-adr	Stock-Other	0.19%	+0.04%	+70.16%
24	STOK	Stoke Therapeutics INC	Stock-Other	0.14%	+0.14%	NEW
25	PRLD	Prelude Therapeutics INC	Stock-Other	0.14%	+0.14%	NEW
26	IBIO	Ibio INC	Stock-Other	0.13%	-0.07%	-28.95%
27	✓	Helix Acquisition CORP Iii	Stock-Other	0.09%	+0.09%	NEW
28	ATRA	Atara Biotherapeutics INC	Stock-Other	0.02%	-0.45%	-82.62%
29	SRZNW	Surrozen Inc-cw25	Stock-Other	0.01%	+0.01%	—

Portfolio Performance

Performance for Q3 2026

+20.8%

Performance Last 4 Quarters

+47.4%

Based on 58% of reported portfolio value with available pricing

Stdev: +31.8%
Beta: +1.03
Alpha: -20.3%
Max Drawdown: -48.4%
Annualized Perf: -7.3%
Batting Avg vs S&P: +43.5%
Sortino: -0.13
Stutzer: -0.03
Treynor: -0.03
Sterling: -0.5
Calmar: -0.15
Information Ratio: -0.68
Tracking Error: +29%
Stdev Down: +21.5%
Winning Months %: +43.5%
Losing Months %: +56.5%
Best 12 Months: +37.1%
Worst 12 Months: -44.9%
Efficiency Ratio: +0.09
Sharpe: -0.09
Stdev Sectors: 0%
Skewness: +0.29
Kurtosis: +0.77
Upside Potential: +1.85

Reported value over time

Sector allocation

Sector allocation over time

Quarterly history

Period	Holdings	Total value	Stability	Top holdings
2026-03-31	30	$2.4B	37	1ZYME 2ANAB 3JAZZ Top holdings2026-03-31 1.ZYME 2.ANAB 3.JAZZ 4.260 5.CRNX 6.AKTS 7.ORIC 8.CGON 9.CRSP 10.ETON
2025-12-31	30	$2.2B	61	1ZYME 2ANAB 3JAZZ Top holdings2025-12-31 1.ZYME 2.ANAB 3.JAZZ 4.CRNX 5.260 6.CRSP 7.MBX 8.IMNM 9.ORIC 10.LKFT
2025-09-30	30	$2.1B	81	1ZYME 2ANAB 3QURE Top holdings2025-09-30 1.ZYME 2.ANAB 3.QURE 4.JAZZ 5.CRNX 6.CRSP 7.TNGX 8.ORIC 9.APLSUSD 10.XNCR
2025-06-30	37	$1.7B	0	1ZYME 2APLSUSD 3JAZZ Top holdings2025-06-30 1.ZYME 2.APLSUSD 3.JAZZ 4.ANAB 5.CRNX 6.2662247D 7.CRSP 8.QURE 9.TNGX 10.XNCR
2025-03-31	46	$1.7B	100	1APLSUSD 2JAZZ 3ZYME Top holdings2025-03-31 1.APLSUSD 2.JAZZ 3.ZYME 4.ANAB 5.CRNX 6.PRTA 7.SRPT 8.XNCR 9.CRSP 10.QURE
2024-12-31	59	$2.6B	0	1APLSUSD 2ZYME 3CRNX Top holdings2024-12-31 1.APLSUSD 2.ZYME 3.CRNX 4.JAZZ 5.PRTA 6.XNCR 7.PFE 8.ARVN 9.ANAB 10.SRPT
2024-09-30	64	$2.9B	0	1APLSUSD 2ANAB 3CRNX Top holdings2024-09-30 1.APLSUSD 2.ANAB 3.CRNX 4.PRTA 5.JAZZ 6.ZYME 7.ARVN 8.KURA 9.XNCR 10.TNGX
2024-06-30	55	$3.3B	0	1APLSUSD 2PRTA 3SRPT Top holdings2024-06-30 1.APLSUSD 2.PRTA 3.SRPT 4.ANAB 5.CRNX 6.ARVN 7.MORFUSD 8.LKFT 9.KURA 10.TNGX
2024-03-31	59	$4.0B	0	1APLSUSD 2PRTA 3ARVN Top holdings2024-03-31 1.APLSUSD 2.PRTA 3.ARVN 4.SRPT 5.CRNX 6.LKFT 7.ANAB 8.ZYME 9.KURA 10.JAZZ
2023-12-31	51	$3.9B	0	1APLSUSD 2MRTXEUR 3PRTA Top holdings2023-12-31 1.APLSUSD 2.MRTXEUR 3.PRTA 4.ARVN 5.LKFT 6.ACAD 7.ANAB 8.ZYME 9.TNGX 10.JAZZ
2023-09-30	51	$3.0B	0	1PRTA 2APLSUSD 3MRTXEUR Top holdings2023-09-30 1.PRTA 2.APLSUSD 3.MRTXEUR 4.LKFT 5.RVMD 6.ANAB 7.ACAD 8.ARVN 9.XNCR 10.TNGX
2023-06-30	53	$4.1B	0	1PRTA 2APLSUSD 3SRPT Top holdings2023-06-30 1.PRTA 2.APLSUSD 3.SRPT 4.JNJ 5.LKFT 6.MORFUSD 7.RVMD 8.ANAB 9.ACAD 10.XNCR
2023-03-31	58	$3.1B	0	1PRTA 2SRPT 3APLSUSD Top holdings2023-03-31 1.PRTA 2.SRPT 3.APLSUSD 4.LKFT 5.ANAB 6.XNCR 7.MORFUSD 8.RVMD 9.ACAD 10.ARVN
2022-12-31	66	$3.3B	0	1PRTA 2SRPT 3APLSUSD Top holdings2022-12-31 1.PRTA 2.SRPT 3.APLSUSD 4.ANAB 5.LKFT 6.XNCR 7.ARVN 8.RVMD 9.MORFUSD 10.ACAD
2022-09-30	76	$3.4B	0	1PRTA 2APLSUSD 3SRPT Top holdings2022-09-30 1.PRTA 2.APLSUSD 3.SRPT 4.ANAB 5.ARVN 6.XNCR 7.LKFT 8.MORFUSD 9.SWTXUSD 10.ACAD
2022-06-30	80	$2.9B	0	1PRTA 2APLSUSD 3SRPT Top holdings2022-06-30 1.PRTA 2.APLSUSD 3.SRPT 4.SGENUSD 5.LKFT 6.ANAB 7.XNCR 8.ARVN 9.KURA 10.MORFUSD
2022-03-31	87	$3.2B	0	1PRTA 2APLSUSD 3LKFT Top holdings2022-03-31 1.PRTA 2.APLSUSD 3.LKFT 4.ANAB 5.SRPT 6.MORFUSD 7.ACAD 8.XNCR 9.KURA 10.RCUS
2021-12-31	76	$3.1B	0	1PRTA 2ANAB 3RCUS Top holdings2021-12-31 1.PRTA 2.ANAB 3.RCUS 4.XNCR 5.APLSUSD 6.MORFUSD 7.LKFT 8.NUVB 9.ALEC 10.PTGX
2021-09-30	71	$2.9B	0	1PRTA 2MORFUSD 3ANAB Top holdings2021-09-30 1.PRTA 2.MORFUSD 3.ANAB 4.RCUS 5.XNCR 6.NUVB 7.ALEC 8.MRTXEUR 9.LKFT 10.STTK
2021-06-30	72	$2.7B	91	1PRTA 2MORFUSD 3ANAB Top holdings2021-06-30 1.PRTA 2.MORFUSD 3.ANAB 4.XNCR 5.RLAY 6.NUVB 7.STTK 8.RCUS 9.ALEC 10.SPRY
2021-03-31	71	$2.3B	57	1PRTA 2XNCR 3MORFUSD Top holdings2021-03-31 1.PRTA 2.XNCR 3.MORFUSD 4.ANAB 5.NUVB 6.RLAY 7.SPRY 8.KURA 9.MRTXEUR 10.ORIC
2020-12-31	67	$1.9B	61	1XNCR 2RLAY 3STTK Top holdings2020-12-31 1.XNCR 2.RLAY 3.STTK 4.SPRY 5.PRTA 6.ORIC 7.MRTXEUR 8.MORFUSD 9.ANAB 10.BIIB
2020-09-30	50	$1.4B	62	1XNCR 2KURA 3RLAY Top holdings2020-09-30 1.XNCR 2.KURA 3.RLAY 4.PRTA 5.MORFUSD 6.MRTXEUR 7.ORIC 8.RNAGBP 9.ANAB 10.64049K
2020-06-30	49	$1.4B	98	1XNCR 2PRTA 3ORIC Top holdings2020-06-30 1.XNCR 2.PRTA 3.ORIC 4.MORFUSD 5.KURA 6.ASMB 7.DRNAUSD 8.ANAB 9.RNAGBP 10.64049K
2020-03-31	51	$957.2M	59	1PRTA 2XNCR 3ARVN Top holdings2020-03-31 1.PRTA 2.XNCR 3.ARVN 4.DRNAUSD 5.FATE 6.IRWD 7.ANAB 8.64049K 9.MORFUSD 10.ASMB
2019-12-31	44	$1.1B	76	1PRTA 2FGENEUR 3XNCR Top holdings2019-12-31 1.PRTA 2.FGENEUR 3.XNCR 4.DRNAUSD 5.KURA 6.IRWD 7.ARVN 8.ASMB 9.64049K 10.MORFUSD
2019-09-30	41	$791.9M	59	1XNCR 2PRTA 3FGENEUR Top holdings2019-09-30 1.XNCR 2.PRTA 3.FGENEUR 4.ONCEEUR 5.KURA 6.ARGX 7.DRNAUSD 8.IRWD 9.MORFUSD 10.SLDB
2019-06-30	40	$989.6M	65	1KURA 2XNCR 3ARGX Top holdings2019-06-30 1.KURA 2.XNCR 3.ARGX 4.FGENEUR 5.CRSP 6.ONCEEUR 7.MRTXEUR 8.DRNAUSD 9.IRWD 10.MORFUSD
2019-03-31	41	$1.1B	79	1ARGX 2KURA 3MRTXEUR Top holdings2019-03-31 1.ARGX 2.KURA 3.MRTXEUR 4.CRSP 5.XNCR 6.ONCEEUR 7.IRWD 8.31572Q 9.DRNAUSD 10.ASND
2018-12-31	54	$999.4M	75	1ARGX 2KURA 3FGENEUR Top holdings2018-12-31 1.ARGX 2.KURA 3.FGENEUR 4.IRWD 5.ASMB 6.ONCEEUR 7.ASND 8.IONS 9.31572Q 10.XNCR
2018-09-30	51	$1.1B	48	1FGENEUR 2ASMB 3IRWD Top holdings2018-09-30 1.FGENEUR 2.ASMB 3.IRWD 4.ASND 5.KURA 6.SRRK 7.DRNAUSD 8.ONCEEUR 9.MGNX 10.RCUS
2018-06-30	35	$1.1B	69	1FGENEUR 2IRWD 3ASMB Top holdings2018-06-30 1.FGENEUR 2.IRWD 3.ASMB 4.ASND 5.KURA 6.MDGL 7.151020 8.SRRK 9.DRNAUSD 10.MGNX
2018-03-31	32	$997.0M	48	1ASMB 2ASND 3FGENEUR Top holdings2018-03-31 1.ASMB 2.ASND 3.FGENEUR 4.IRWD 5.KURA 6.WVE 7.ARRYEUR 8.DRNAUSD 9.MGNX 10.RCUS
2017-12-31	31	$888.1M	72	1ASMB 2FGENEUR3151020 Top holdings2017-12-31 1.ASMB 2.FGENEUR 3.151020 4.IRWD 5.ASND 6.KURA 7.DRNAUSD 8.ARRYEUR 9.WVE 10.MYOKEUR
2017-09-30	40	$750.3M	88	1ASMB 2FGENEUR 3IRWD Top holdings2017-09-30 1.ASMB 2.FGENEUR 3.IRWD 4.ASND 5.KURA 6.IMMU 7.MYOKEUR 8.LKFT 9.MRNSUSD 10.LIFEUSD
2017-06-30	36	$563.2M	75	10153512IRWD 3ASMB Top holdings2017-06-30 1.015351 2.IRWD 3.ASMB 4.FGENEUR 5.LKFT 6.ASND 7.GILD 8.SGMOQ 9.KURA 10.888846
2017-03-31	33	$395.6M	84	1ASMB 2IRWD 3LKFT Top holdings2017-03-31 1.ASMB 2.IRWD 3.LKFT 4.GILD 5.ASND 6.KURA 7.TBPH 3.25 11-01-23 8.ACRS 9.CTMX 10.14740B
2016-12-31	30	$299.4M	87	1IRWD 2LKFT 3ASMB Top holdings2016-12-31 1.IRWD 2.LKFT 3.ASMB 4.ALXN 5.ASND 6.TBPH 3.25 11-01-23 7.ARDX 8.KURA 9.FPRX 10.ACRS
2016-09-30	31	$325.9M	88	1IRWD 2LKFT 3BMY Top holdings2016-09-30 1.IRWD 2.LKFT 3.BMY 4.ASMB 5.DERMEUR 6.ARDX 7.KURA 8.FPRX 9.FGENEUR 10.GILD
2016-06-30	32	$253.6M	87	1IRWD 2LKFT 3RTRXEUR Top holdings2016-06-30 1.IRWD 2.LKFT 3.RTRXEUR 4.CYTK 5.ASMB 6.FGENEUR 7.XLRN 8.GILD 9.G0177J 10.ITCIEUR
2016-03-31	37	$286.2M	82	1IRWD 2FPRX 3EPZMEUR Top holdings2016-03-31 1.IRWD 2.FPRX 3.EPZMEUR 4.FGENEUR 5.ARRY 3 06-01-20 6.RTRXEUR 7.78464A 8.CYTK 9.GILD 10.ASMB
2015-12-31	31	$318.4M	78	1FGENEUR 2FPRX3G50871 Top holdings2015-12-31 1.FGENEUR 2.FPRX 3.G50871 4.RTRXEUR 5.ARRY 3 06-01-20 6.KURA 7.ASMB 8.CYTK 9.91911K 10.COLL
2015-09-30	25	$219.7M	56	1FGENEUR 2ATRAGBX 3ARRY 3 06-01-20 Top holdings2015-09-30 1.FGENEUR 2.ATRAGBX 3.ARRY 3 06-01-20 4.RTRXEUR 5.EPZMEUR 6.ASMB 7.KRG 8.33938A 9.COLL 10.LIFEUSD
2015-06-30	27	$299.9M	69	1ATRAGBX 2EPZMEUR 3ASMB Top holdings2015-06-30 1.ATRAGBX 2.EPZMEUR 3.ASMB 4.FGENEUR 5.ARRY 3 06-01-20 6.KRG 7.33938A 8.LIFEUSD 9.RTRXEUR 10.KIN1USD
2015-03-31	24	$300.1M	85	1ATRAGBX 2EPZMEUR3756207 Top holdings2015-03-31 1.ATRAGBX 2.EPZMEUR 3.756207 4.IRWD 5.ARRY 3 06-01-20 6.ASMB 7.189464 8.CLVSEUR 9.KRG 10.33938A
2014-12-31	22	$197.6M	0	1KRG 2CLVSEUR3756207 Top holdings2014-12-31 1.KRG 2.CLVSEUR 3.756207 4.ARRY 3 06-01-20 5.MGNX 6.IRWD 7.FGENEUR 8.ATRAGBX 9.KIN1USD 10.SG7

Holding changes this quarter

EcoR1 Capital, LLC's most significant position changes for 2026-03-31: New buy: Aktis Oncology INC (AKTS); Sold out: Immunome INC (IMNM); Sold out: Structure Therapeutics INC (GPCR); Sold out: Vaxcyte INC (PCVX); New buy: Relay Therapeutics INC (RLAY).

Position changes disclosed by EcoR1 Capital, LLC for the quarter ending 2026-03-31, including ticker, issuer, weight change, shares change, and action
#	Ticker	Issuer	Weight Change	Shares Change	Action
1	260	Centessa Pharmaceuticals-adr	+7.3%	+105.80%	Add
2	ANAB	Anaptysbio INC	+1.2%	—	Unchanged
3	CGON	Cg Oncology INC	+1.2%	+3.49%	Add
4	ORIC	Oric Pharmaceuticals INC	+1.1%	—	Unchanged
5	ETON	Eton Pharmaceuticals INC	+0.7%	+6.96%	Add
6	JAZZ	Jazz Pharmaceuticals plc	+0.5%	—	Unchanged
7	MREO	Mereo Biopharma Group Pl-adr	0%	+70.16%	Add
8	SRZNW	Surrozen Inc-cw25	0%	—	Unchanged
9	IBIO	Ibio INC	-0.1%	-28.95%	Trim
10	NGNE	Neurogene INC	-0.1%	—	Unchanged
11	LKFT	Lakefront Biotherapeutic-adr	-0.4%	—	Unchanged
12	ATRA	Atara Biotherapeutics INC	-0.5%	-82.62%	Trim
13	CRSP	CRISPR Therapeutics AG	-0.5%	—	Unchanged
14	BBOT	Bridgebio Oncology Therapeut	-0.5%	—	Unchanged
15	ZBIO	Zenas Biopharma INC	-0.6%	—	Unchanged
16	XNCR	Xencor INC	-1.2%	-34.22%	Trim
17	MBX	Mbx Biosciences INC	-2.1%	-63.41%	Trim
18	CRNX	Crinetics Pharmaceuticals In	-2.5%	—	Unchanged
19	ZYME	Zymeworks INC	-3%	—	Unchanged
20	AKTS	Aktis Oncology INC	—	NEW	New buy
21	IMNM	Immunome INC	—	EXIT	Sold out
22	GPCR	Structure Therapeutics INC	—	EXIT	Sold out
23	PCVX	Vaxcyte INC	—	EXIT	Sold out
24	RLAY	Relay Therapeutics INC	—	NEW	New buy
25	AQST	Aquestive Therapeutics INC	—	EXIT	Sold out
26	VYGR	Voyager Therapeutics INC	—	EXIT	Sold out
27	ERAS	Erasca INC	—	NEW	New buy
28	MNKD	Mannkind CORP	—	EXIT	Sold out
29	NUVB-WS	Nuvation Bio INC -cw27	—	EXIT	Sold out
30	EIKN	Eikon Therapeutics INC	—	NEW	New buy
31	REPL	Replimune Group INC	—	NEW	New buy
32	✓	Zura Bio LTD	—	NEW	New buy
33	PHAT	Phathom Pharmaceuticals INC	—	NEW	New buy
34	EOLS	Evolus INC	—	EXIT	Sold out
35	STOK	Stoke Therapeutics INC	—	NEW	New buy
36	PRLD	Prelude Therapeutics INC	—	NEW	New buy
37	✓	Helix Acquisition CORP Iii	—	NEW	New buy
38	CAMP	Camp4 Therapeutics CORP	—	EXIT	Sold out

FAQ

What is EcoR1 Capital, LLC and what type of investor is it?

EcoR1 Capital, LLC is a investment manager that files SEC Form 13F quarterly, disclosing its U.S. public equity holdings to regulators. As of the most recent reporting period (2026-03-31), the firm manages a tracked equity portfolio valued at approximately $2.4B, spread across 30 disclosed positions.

What are EcoR1 Capital, LLC's largest equity positions?

Based on the latest 13F filing, EcoR1 Capital, LLC's top holdings by market value are: 1. Zymeworks INC (ZYME) — $575.2M (24.4%) 2. Anaptysbio INC (ANAB) — $437.0M (18.6%) 3. Jazz Pharmaceuticals plc (JAZZ) — $322.6M (13.7%) 4. Centessa Pharmaceuticals-adr (260) — $254.6M (10.8%) 5. Crinetics Pharmaceuticals In (CRNX) — $155.7M (6.6%)

What changes did EcoR1 Capital, LLC make in its most recent portfolio filing?

In the latest reported quarter, EcoR1 Capital, LLC made 27 notable position adjustments: 10 new positions were initiated, 4 existing holdings were added to, 4 positions were partially reduced, and 9 were completely exited. The largest of these moves: New buy: Aktis Oncology INC (AKTS); Sold out: Immunome INC (IMNM); Sold out: Structure Therapeutics INC (GPCR); Sold out: Vaxcyte INC (PCVX); New buy: Relay Therapeutics INC (RLAY)

What sectors does EcoR1 Capital, LLC focus on?

EcoR1 Capital, LLC is concentrated in the following sectors based on its current disclosed equity portfolio: • Health Care: 100.0%