Siren, L.L.C.

CIK

2005245

Location

New York, NY

Portfolio Value

Mid $3,590,811,251

Diversification

Diversified

Filing Date

Global Rank

#662 / 8,232 ▲ 96

Top Industry

Biotechnology 93.1%

3Y Alpha vs SPY

+9.2%

Period ended 2 months ago

Filed May 14, 2026 · 30d

7 quarters · since Sep 2024

Clone Performance

Nov 2024–Jun 2026 · vs SPY

Hypothetical growth of cloning every reported 13F position and rebalancing on each filing, indexed to the same start.

Cloned portfolio

+43.4%

SPY

+27.3%

Annualised alpha

+9.2%

Max drawdown

−42.4%

Estimate. 13F holdings are quarter-lagged and long-only, so the clone rebalances about 45 days after each period end — when the filing becomes public — and excludes options and short positions. Past performance does not predict future results.

Portfolio Concentration

99 positions · as of Mar 31, 2026 · Δ vs Dec 31, 2025

Top Position

14.8%

+0.3 pts

Top 5

35.0%

+1.4 pts

Top 10

50.0%

+2.7 pts

HHI

433

Diversified+13

Portfolio Trend

7 quarters · across all stocks

Sector Breakdown

As of Mar 31, 2026

Sector	% Portfolio	Value	Positions
Healthcare	93.6%	$3,360,957,936	69
Technology	3.7%	$133,189,061	18
Communication Services	1.7%	$61,587,576	3
Consumer Cyclical	0.8%	$27,874,460	4
Industrials	0.1%	$2,927,000	1
Financial Services	0.1%	$1,836,718	2
Real Estate	0.0%	$1,497,000	1
Consumer Defensive	0.0%	$941,500	1

Last Quarter's Activity

Export CSV

Mar 31, 2026 vs Dec 31, 2025

Added To

Positions the filer increased

25 positions

Ticker	Company	Δ Shares	Shares	Value
LXRX	Lexicon Pharmaceuticals, Inc.	+5,384,615	44,303,518	$69,113,488
ERAS	Erasca, Inc.	+2,486,997	11,244,246	$181,931,900
ZURA	Zura Bio Ltd	+2,434,866	3,734,866	$22,222,452
ORIC	Oric Pharmaceuticals, Inc.	+1,990,617	2,998,192	$37,987,092
ENGN	enGene Therapeutics Inc.	+1,916,895	5,253,159	$35,774,012
OLMA	Olema Pharmaceuticals, Inc.	+1,456,249	4,756,949	$70,926,109
BCAX	Bicara Therapeutics Inc.	+586,001	5,802,970	$115,421,073
XENE	Xenon Pharmaceuticals Inc.	+505,803	1,318,564	$76,674,496
FULC	Fulcrum Therapeutics, Inc.	+400,000	2,350,000	$18,024,500
CRNX	Crinetics Pharmaceuticals, Inc.	+396,000	1,903,636	$69,140,059
GPCR	Structure Therapeutics Inc.	+250,000	1,328,698	$64,043,243
RYTM	Rhythm Pharmaceuticals, Inc.	+225,536	725,511	$63,097,691
PVLA	Palvella Therapeutics, Inc.	+182,485	257,485	$32,095,505
CLBT	Cellebrite DI Ltd.	+161,544	311,544	$4,293,076
ARWR	Arrowhead Pharmaceuticals, Inc.	+115,000	1,615,476	$101,290,345
COGT	Cogent Biosciences, Inc.	+80,000	1,709,279	$65,790,148
MNPR	Monopar Therapeutics	+57,820	270,118	$14,799,765
NVDA	Nvidia Corp	+51,600	89,085	$15,536,424
NOW	ServiceNow, Inc.	+51,460	87,090	$9,105,259
GOOGL	Alphabet Inc.	+45,000	65,703	$18,893,554
NBIS	Nebius Group N.V.	+37,396	113,614	$11,788,588
FROG	JFrog Ltd	+35,200	128,816	$6,045,334
DT	Dynatrace, Inc.	+34,771	150,000	$5,547,000
MSFT	Microsoft Corp	+26,380	41,380	$15,317,634
FIG	Figma, Inc.	+25,000	50,000	$1,057,000
No positions match the current search.

Trimmed

Positions the filer reduced

18 positions

Ticker	Company	Δ Shares	Shares	Value
CNTA	Centessa Pharmaceuticals plc	−2,974,053	1,053,464	$41,843,590
TNGX	Tango Therapeutics, Inc.	−2,508,269	5,657,105	$118,346,636
SEER	Seer, Inc.	−1,541,327	2,458,673	$4,130,570
TSHA	Taysha Gene Therapies, Inc.	−1,300,000	8,829,913	$39,469,711
DYN	Dyne Therapeutics, Inc.	−1,273,816	2,229,125	$40,414,036
TRVI	Trevi Therapeutics, Inc.	−500,000	1,786,867	$21,317,323
BCYC	Bicycle Therapeutics PLC	−451,870	1,560,882	$7,242,492
STOK	Stoke Therapeutics, Inc.	−252,000	1,995,347	$64,968,498
RVMD	Revolution Medicines, Inc.	−224,095	1,110,980	$108,042,805
KYMR	Kymera Therapeutics, Inc.	−100,000	3,186,830	$265,431,070
EWTX	Edgewise Therapeutics, Inc.	−99,727	4,430,263	$139,553,284
RELY	Remitly Global, Inc.	−75,000	1,543,271	$24,183,056
RAPP	Rapport Therapeutics, Inc.	−67,000	641,469	$20,071,565
MDLN	Medline Inc.	−50,000	25,000	$1,112,500
BEKE	KE Holdings Inc.	−45,000	100,000	$1,497,000
ONC	BeOne Medicines Ltd.	−35,000	465,000	$138,091,050
PRMB	Primo Brands Corp	−25,000	50,000	$941,500
AMZN	Amazon Com Inc	−4,859	46,641	$9,713,921
No positions match the current search.

New Positions

Positions the filer opened this quarter

19 positions

Ticker	Company	Shares	Value
MANE	Veradermics, Inc	1,505,374	$95,064,368
CYTK	Cytokinetics Inc	613,952	$40,465,576
ELVN	Enliven Therapeutics, Inc.	746,226	$29,252,059
DMRA	Damora Therapeutics, Inc.	900,000	$23,310,000
ANNX	Annexon, Inc.	3,958,646	$21,930,898
DFTX	Definium Therapeutics, Inc.	919,493	$17,378,417
AMLX	Amylyx Pharmaceuticals, Inc.	1,230,000	$17,097,000
QURE	uniQure N.V.	1,000,000	$16,350,000
CTMX	CytomX Therapeutics, Inc.	3,457,711	$16,251,241
RZLT	Rezolute, Inc.	3,328,287	$10,151,275
GENB	Generate Biomedicines, Inc.	736,104	$9,201,300
ABSI	Absci Corp	1,800,000	$5,400,000
MSLE	Satellos Bioscience Inc.	892,074	$5,022,376
AGMB	Agomab Therapeutics NV	411,250	$4,314,012
FPS	Forgent Power Solutions, Inc.	100,000	$2,927,000
MU	Micron Technology Inc	6,000	$2,027,040
AS	Amer Sports, Inc.	50,000	$1,646,000
AEVA	Aeva Technologies, Inc.	110,000	$1,447,600
NU	Nu Holdings Ltd.	25,000	$359,250
No positions match the current search.

Sold Out

Positions the filer fully exited

25 positions

Ticker	Company	Shares	Value
APLS	Apellis Pharmaceuticals, Inc.	2,578,396	$64,769,307
ASND	Ascendis Pharma A/S	235,862	$50,295,212
ZYME	Zymeworks Inc.	1,680,121	$44,237,585
MLYS	Mineralys Therapeutics, Inc.	699,999	$25,402,963
IHS	IHS Holding Ltd	2,357,520	$17,587,099
UPB	Upstream Bio, Inc.	588,450	$15,976,417
BNTC	Benitec Biopharma Inc.	775,000	$10,439,250
LXEO	Lexeo Therapeutics, Inc.	720,622	$7,155,776
CRM	Salesforce, Inc.	26,100	$6,914,151
CMPS	COMPASS Pathways plc	1,000,000	$6,900,000
BLLN	BillionToOne, Inc.	83,833	$6,860,892
SVRA	Savara Inc	1,000,000	$6,030,000
XFOR	X4 Pharmaceuticals, Inc	1,500,000	$6,000,000
ALMS	Alumis Inc.	500,000	$4,880,000
META	Meta Platforms, Inc.	7,169	$4,732,185
PEPG	PepGen Inc.	700,000	$4,557,000
SGMT	Sagimet Biosciences Inc.	724,771	$4,290,644
ADBE	Adobe Inc.	12,051	$4,217,729
EDU	New Oriental Education & Technology Group Inc.	62,000	$3,411,860
ZS	Zscaler, Inc.	12,000	$2,699,040
BDTX	Black Diamond Therapeutics, Inc.	1,046,517	$2,543,036
QCOM	Qualcomm Inc/De	14,000	$2,394,700
ARM	Arm Holdings PLC /Uk	21,500	$2,350,165
TIL	Instil Bio, Inc.	203,933	$2,243,263
PANW	Palo Alto Networks Inc	11,450	$2,109,090
No positions match the current search.

Portfolio Positions

Compact Export CSV View 13F filing

99 positions · $3,590,811,251 total · as of Mar 31, 2026

All sectors Communication Services Consumer Cyclical Consumer Defensive Financial Services Healthcare Industrials Real Estate Technology

Showing 1–50 of 99 positions by value · page 1 of 2

Ticker	Company	Type	Shares	Δ Shares	Value (USD)	% Δ Value	% of Portfolio
SRRK	Scholar Rock Holding Corp Healthcare	Held	10,825,013	0	$532,157,639	+11.6%	14.82%
KYMR	Kymera Therapeutics, Inc. Healthcare	Reduced	3,186,830	-100,000	$265,431,070	+3.8%	7.39%
ERAS	Erasca, Inc. Healthcare	Added	11,244,246	+2,486,997	$181,931,900	+458.5%	5.07%
EWTX	Edgewise Therapeutics, Inc. Healthcare	Reduced	4,430,263	-99,727	$139,553,284	+24.1%	3.89%
ONC	BeOne Medicines Ltd. Healthcare	Reduced	465,000	-35,000	$138,091,050	−9.1%	3.85%
TNGX	Tango Therapeutics, Inc. Healthcare	Reduced	5,657,105	-2,508,269	$118,346,636	+63.6%	3.30%
BCAX	Bicara Therapeutics Inc. Healthcare	Added	5,802,970	+586,001	$115,421,073	+31.5%	3.21%
RVMD	Revolution Medicines, Inc. Healthcare	Reduced	1,110,980	-224,095	$108,042,805	+1.6%	3.01%
ARWR	Arrowhead Pharmaceuticals, Inc. Healthcare	Added	1,615,476	+115,000	$101,290,345	+1.7%	2.82%
MANE	Veradermics, Inc Healthcare	NEW	1,505,374	NEW	$95,064,368	NEW	2.65%
XENE	Xenon Pharmaceuticals Inc. Healthcare	Added	1,318,564	+505,803	$76,674,496	+110.5%	2.14%
OLMA	Olema Pharmaceuticals, Inc. Healthcare	Added	4,756,949	+1,456,249	$70,926,109	−14.0%	1.98%
CRNX	Crinetics Pharmaceuticals, Inc. Healthcare	Added	1,903,636	+396,000	$69,140,059	−1.5%	1.93%
LXRX	Lexicon Pharmaceuticals, Inc. Healthcare	Added	44,303,518	+5,384,615	$69,113,488	+54.4%	1.92%
COGT	Cogent Biosciences, Inc. Healthcare	Added	1,709,279	+80,000	$65,790,148	+13.7%	1.83%
STOK	Stoke Therapeutics, Inc. Healthcare	Reduced	1,995,347	-252,000	$64,968,498	−8.9%	1.81%
RCUS	Arcus Biosciences, Inc. Healthcare	Held	3,007,077	0	$64,952,863	−9.4%	1.81%
GPCR	Structure Therapeutics Inc. Healthcare	Added	1,328,698	+250,000	$64,043,243	−14.6%	1.78%
IRON	Disc Medicine, Inc. Healthcare	Held	988,401	0	$63,198,359	−19.5%	1.76%
RYTM	Rhythm Pharmaceuticals, Inc. Healthcare	Added	725,511	+225,536	$63,097,691	+17.9%	1.76%
SLDB	Solid Biosciences Inc. Healthcare	Held	7,690,405	0	$55,370,916	+27.7%	1.54%
SEPN	Septerna, Inc. Healthcare	Held	2,000,000	0	$48,060,000	−13.8%	1.34%
CNTA	Centessa Pharmaceuticals plc Healthcare	Reduced	1,053,464	-2,974,053	$41,843,590	−58.5%	1.17%
SYRE	Spyre Therapeutics, Inc. Healthcare	Held	818,598	0	$41,290,083	+54.0%	1.15%
CYTK	Cytokinetics Inc Healthcare	NEW	613,952	NEW	$40,465,576	NEW	1.13%
DYN	Dyne Therapeutics, Inc. Healthcare	Reduced	2,229,125	-1,273,816	$40,414,036	−41.0%	1.13%
TSHA	Taysha Gene Therapies, Inc. Healthcare	Reduced	8,829,913	-1,300,000	$39,469,711	−29.2%	1.10%
DBVT	DBV Technologies S.A. Healthcare	Held	1,857,362	0	$38,800,292	+9.0%	1.08%
ORIC	Oric Pharmaceuticals, Inc. Healthcare	Added	2,998,192	+1,990,617	$37,987,092	+360.9%	1.06%
ENGN	enGene Therapeutics Inc. Healthcare	Added	5,253,159	+1,916,895	$35,774,012	+18.7%	1.00%
PVLA	Palvella Therapeutics, Inc. Healthcare	Added	257,485	+182,485	$32,095,505	+308.8%	0.89%
TBLA	Taboola.com Ltd. Communication Services	Held	9,969,495	0	$30,905,434	−32.8%	0.86%
ELVN	Enliven Therapeutics, Inc. Healthcare	NEW	746,226	NEW	$29,252,059	NEW	0.81%
DNLI	Denali Therapeutics Inc. Healthcare	Held	1,396,513	0	$26,813,049	+16.3%	0.75%
RELY	Remitly Global, Inc. Technology	Reduced	1,543,271	-75,000	$24,183,056	+8.3%	0.67%
DMRA	Damora Therapeutics, Inc. Healthcare	NEW	900,000	NEW	$23,310,000	NEW	0.65%
ZURA	Zura Bio Ltd Healthcare	Added	3,734,866	+2,434,866	$22,222,452	+226.2%	0.62%
ANNX	Annexon, Inc. Healthcare	NEW	3,958,646	NEW	$21,930,898	NEW	0.61%
TRVI	Trevi Therapeutics, Inc. Healthcare	Reduced	1,786,867	-500,000	$21,317,323	−25.5%	0.59%
RAPP	Rapport Therapeutics, Inc. Healthcare	Reduced	641,469	-67,000	$20,071,565	−6.6%	0.56%
GOOGL	Alphabet Inc. Communication Services	Added	65,703	+45,000	$18,893,554	+191.6%	0.53%
FULC	Fulcrum Therapeutics, Inc. Healthcare	Added	2,350,000	+400,000	$18,024,500	−18.3%	0.50%
WVE	Wave Life Sciences Ltd. Healthcare	Held	2,450,000	0	$17,762,500	−57.4%	0.49%
DFTX	Definium Therapeutics, Inc. Healthcare	NEW	919,493	NEW	$17,378,417	NEW	0.48%
AMLX	Amylyx Pharmaceuticals, Inc. Healthcare	NEW	1,230,000	NEW	$17,097,000	NEW	0.48%
CGEM	Cullinan Therapeutics, Inc. Healthcare	Held	1,193,410	0	$16,958,356	+37.3%	0.47%
QURE	uniQure N.V. Healthcare	NEW	1,000,000	NEW	$16,350,000	NEW	0.46%
CTMX	CytomX Therapeutics, Inc. Healthcare	NEW	3,457,711	NEW	$16,251,241	NEW	0.45%
NVDA	Nvidia Corp Technology	Added	89,085	+51,600	$15,536,424	+122.2%	0.43%
SLN	Silence Therapeutics plc Healthcare	Held	2,911,438	0	$15,343,278	−13.3%	0.43%