Siren, L.L.C.

In its 13F for Q2 2026 (holdings as of June 30, 2026, filed August 13, 2026), Siren, L.L.C. reported 115 stock positions worth $4.9 billion. Its top holding was Scholar Rock (SRRK) at 10.7% of the portfolio, followed by Kymera Therapeutics (KYMR, 6.8%) and Erasca (ERAS, 4.2%). Compared with Q1 2026, it opened 24 new positions, sold out of 9, added to 32 and reduced 21. The biggest buy was a new position in Parabilis Medicines (PBLS) and the biggest sale Scholar Rock (SRRK, shares −12%).

Most Recent 13F
Q2 2026
Location
New York, NY
CIK
0002005245
Portfolio Value
$4.9B (Q2 2026)
SEC Filing
0002005245-26-000008 ↗ filed Aug 13, 2026

Holdings Value

0$1.0B$2.0B$3.0B$4.0B$5.0B Q3 2024: $2.0B Q3 2024 Q4 2024: $2.3B Q4 2024 Q1 2025: $1.8B Q1 2025 Q2 2025: $1.9B Q2 2025 Q3 2025: $2.6B Q3 2025 Q4 2025: $3.4B Q4 2025 Q1 2026: $3.6B Q1 2026 Q2 2026: $4.9B $4.9B Q2 2026

Holdings 115 stocks · $4.9B
SRRK Scholar Rock Holding Corp. 10.69% 9,575,013 $526.6M Reduce -11.6%
KYMR Kymera Therapeutics Inc. 6.83% 2,935,830 $336.7M Reduce -7.9%
ERAS Erasca Inc. 4.24% 11,397,781 $208.8M Add +1.4%
MANE Veradermics Inc. 4.13% 1,655,374 $203.5M Add +10.0%
TNGX Tango Therapeutics Inc. 3.92% 6,179,364 $193.2M Add +9.2%
RVMD Revolution Medicines Inc. 3.42% 900,000 $168.6M Reduce -19.0%
BCAX Bicara Therapeutics Inc. 3.38% 5,602,970 $166.4M Reduce -3.5%
ARWR Arrowhead Pharmaceuticals Inc. 2.84% 1,715,476 $139.8M Add +6.2%
ONC Beone Medicines Ltd.-ADR 2.69% 465,000 $132.5M No change
EWTX Edgewise Therapeutics Inc. 2.63% 3,184,629 $129.4M Reduce -28.1%
RYTM Rhythm Pharmaceuticals Inc. 2.56% 1,136,275 $126.2M Add +56.6%
LXRX Lexicon Pharmaceuticals Inc. 2.16% 44,303,518 $106.3M No change
ELVN Enliven Therapeutics Inc. 1.83% 1,774,411 $90.1M Add +137.8%
SYRE Spyre Therapeutics Inc. 1.75% 968,598 $86.0M Add +18.3%
PBLS Parabilis Medicines Inc. 1.66% 2,992,259 $81.9M New
XENE Xenon Pharmaceuticals Inc. 1.62% 1,318,564 $79.6M No change
SLDB Solid Biosciences Inc. 1.56% 7,690,405 $76.8M No change
ABVX Abivax SA-ADR 1.56% 576,000 $76.8M New
COAG Hemab Therapeutics Holdings 1.56% 2,086,834 $76.6M New
RCUS Arcus Biosciences Inc. 1.51% 2,420,430 $74.6M Reduce -19.5%
COGT Cogent Biosciences Inc. 1.46% 1,859,279 $72.0M Add +8.8%
RLAY Relay Therapeutics Inc. 1.39% 3,650,000 $68.3M New
TSHA Taysha Gene Therapies Inc. 1.36% 9,846,579 $67.1M Add +11.5%
DFTX Definium Therapeutics Inc. 1.36% 1,419,493 $66.8M Add +54.4%
STOK Stoke Therapeutics Inc. 1.33% 1,995,347 $65.3M No change
IRON Disc Medicine Inc. 1.32% 888,401 $65.0M Reduce -10.1%
CYTK Cytokinetics Inc. 1.31% 758,952 $64.7M Add +23.6%
SEPN Septerna Inc. 1.29% 1,900,000 $63.6M Reduce -5.0%
OLMA Olema Pharmaceuticals Inc. 1.23% 4,856,949 $60.8M Add +2.1%
CRNX Crinetics Pharmaceuticals Inc. 1.08% 1,420,788 $53.2M Reduce -25.4%
KLRA Kailera Therapeutics Inc. 0.99% 2,214,286 $48.8M New
DYN Dyne Therapeutics Inc. 0.96% 2,129,125 $47.3M Reduce -4.5%
GPCR Structure Therapeutics Inc. 0.95% 872,967 $46.9M Reduce -34.3%
TBLA Taboola.com Ltd. 0.85% 8,423,410 $42.1M Reduce -15.5%
PVLA Palvella Therapeutics Inc. 0.80% 257,485 $39.3M No change
SLN Silence Therapeutics PLC-ADR 0.74% 3,311,438 $36.4M Add +13.7%
DNLI Denali Therapeutics Inc. 0.73% 1,396,513 $35.9M No change
RELY Remitly Global Inc. 0.70% 1,543,271 $34.6M No change
CGEM Cullinan Therapeutics Inc. 0.70% 1,893,410 $34.5M Add +58.7%
COF Capital One Financial Corp. 0.70% 171,615 $34.4M New
TRVI Trevi Therapeutics Inc. 0.68% 1,786,867 $33.3M No change
ORIC Oric Pharmaceuticals Inc. 0.66% 2,998,192 $32.5M No change
GOOGL Alphabet Inc. Class A 0.65% 90,000 $32.2M Add +37.0%
DBVT DBV Technologies SA-Spon ADR 0.62% 1,857,362 $30.5M No change
ABSI Absci Corp. 0.58% 2,474,764 $28.7M Add +37.5%
SION Sionna Therapeutics Inc. 0.55% 610,515 $26.9M Add +103.5%
RAPP Rapport Therapeutics Inc. 0.54% 641,469 $26.7M No change
AMLX Amylyx Pharmaceuticals Inc. 0.54% 1,480,586 $26.6M Add +20.4%
ANNX Annexon Inc. 0.52% 4,458,646 $25.5M Add +12.6%
MNPR Monopar Therapeutics Inc. 0.51% 270,118 $25.0M No change
ORKA Oruka Therapeutics Inc. 0.48% 250,000 $23.8M New
SPTX Seaport Therapeutics Inc. 0.48% 1,095,316 $23.8M New
DMRA Damora Therapeutics Inc. 0.48% 900,000 $23.4M No change
TYRA Tyra Biosciences Inc. 0.47% 725,000 $23.2M New
ZURA Zura Bio Ltd. 0.45% 3,734,866 $22.0M No change
TSM Taiwan Semiconductor-SP ADR 0.43% 44,700 $21.3M Add +5.9%
NVDA Nvidia Corp. 0.39% 95,000 $19.0M Add +6.6%
RZLT Rezolute Inc. 0.35% 3,328,287 $17.3M No change
MPLT Maplight Therapeutics Inc. 0.33% 450,000 $16.1M No change
NMRA Neumora Therapeutics Inc. 0.29% 8,497,822 $14.4M No change
NBIS Nebius Group NV 0.29% 52,000 $14.4M Reduce -54.2%
MSFT Microsoft Corp. 0.28% 37,500 $14.0M Reduce -9.4%
CTMX Cytomx Therapeutics Inc. 0.26% 3,457,711 $13.0M No change
GENB Generate Biomedicines Inc. 0.25% 736,104 $12.4M No change
IKT Inhibikase Therapeutics Inc. 0.24% 5,850,000 $11.9M No change
ADAG Adagene Inc.-ADR 0.23% 2,666,666 $11.2M New
ENGN Engene Therapeutics Inc. 0.22% 6,256,662 $10.8M Add +19.1%
WHWK Whitehawk Therapeutics Inc. 0.22% 2,337,102 $10.7M Add +12.3%
DDOG Datadog Inc. Class A 0.21% 40,000 $10.4M Reduce -26.3%
NOW ServiceNow Inc. 0.20% 100,000 $9.9M Add +14.8%
AVGO Broadcom Inc. 0.19% 25,000 $9.4M Add +66.7%
IONQ Ionq Inc. 0.18% 170,000 $9.1M No change
FROG Jfrog Ltd. 0.18% 95,500 $8.7M Reduce -25.9%
OCS Oculis Holding AG 0.18% 625,000 $8.7M New
IREN Iren Ltd. filed as IREN LIMITED 0.16% 175,000 $8.0M Add +306.0%
AMZN Amazon.com Inc. 0.16% 32,500 $7.7M Reduce -30.3%
CRWD CrowdStrike Holdings Inc. Class A 0.15% 10,000 $7.6M Reduce -56.6%
DSGN Design Therapeutics Inc. 0.15% 523,212 $7.6M New
PDD PDD Holdings Inc. 0.15% 95,000 $7.2M Add +13.9%
MSLE Satellos Bioscience Inc. 0.14% 892,074 $6.9M No change
DT Dynatrace Inc. 0.14% 155,000 $6.8M Add +3.3%
TENX Tenax Therapeutics Inc. 0.13% 427,141 $6.2M No change
VTVT VTV Therapeutics Inc. Class A 0.12% 163,000 $6.1M No change
ELOX Eloxx Pharmaceuticals Inc. 0.11% 400,000 $5.6M New
AGMB Agomab Therapeutics NV 0.11% 411,250 $5.3M No change
BABA Alibaba Group Holding-SP ADR 0.10% 50,000 $4.8M New
KRRO Korro Bio Inc. 0.09% 347,718 $4.6M No change
CLBT Cellebrite Di Ltd. 0.09% 311,544 $4.5M No change
IVVD Invivyd Inc. 0.09% 5,000,000 $4.4M Add +25.0%
OUST Ouster Inc. 0.09% 67,500 $4.2M New
PALI Palisade Bio Inc. 0.08% 2,000,000 $4.2M New
AEVA Aeva Technologies Inc. 0.08% 145,459 $4.2M Add +32.2%
SEER Seer Inc. 0.08% 2,458,673 $4.1M No change
NBP Novabridge Biosciences 0.08% 2,004,739 $3.9M Reduce -33.2%
GTLB Gitlab Inc. Class A 0.08% 125,000 $3.8M Add +25.0%
ODTX Odyssey Therapeutics Inc. 0.08% 200,000 $3.7M New
FHTX Foghorn Therapeutics Inc. 0.07% 720,720 $3.5M No change
AGEN Agenus Inc. 0.07% 1,064,250 $3.3M No change
MNDY Monday.com Ltd. 0.06% 42,500 $3.1M Add +70.0%
ZTS Zoetis Inc. 0.05% 35,000 $2.5M New
WK Workiva Inc. 0.04% 45,000 $2.2M Reduce -51.4%
NFLX Netflix Inc. 0.04% 25,000 $1.8M New
KLRS Kalaris Therapeutics Inc. 0.04% 435,798 $1.8M No change
QNT Quantinuum Inc. Class A 0.03% 20,000 $1.6M New
RANI Rani Therapeutics Holdings Class A 0.03% 2,000,000 $1.5M No change
TSLA Tesla Inc. 0.03% 3,500 $1.5M Reduce -83.7%
BEKE Ke Holdings Inc.-ADR filed as KE HLDGS INC 0.03% 100,000 $1.5M No change
ENTX Entera Bio Ltd. 0.03% 736,457 $1.3M New
MDLN Medline Inc. Class A 0.02% 25,000 $986K No change
LITE Lumentum Holdings Inc. 0.02% 1,055 $905K New
FIG Figma Inc. Class A 0.02% 50,000 $905K No change
GOSS Gossamer Bio Inc. 0.02% 5,208,968 $857K No change
FOXA Fox Corp. Class A 0.01% 10,000 $522K New
T AT&T Inc. 0.01% 25,000 $518K New
NU Nu Holdings Ltd./Cayman Isl-A filed as NU HLDGS LTD 0.01% 25,000 $334K No change

Options reported separately and not counted above: MSFT calls ($9.0M), AAPL calls ($6.7M).

Portfolio Sells Q1 2026 → Q2 2026
SRRK Scholar Rock Holding Corp. Reduce -11.6% 10.69% −4.06
EWTX Edgewise Therapeutics Inc. Reduce -28.1% 2.63% −1.24
CNTA Centessa Pharmaceuticals Ltd. Sold out 0.00% −1.16
CRNX Crinetics Pharmaceuticals Inc. Reduce -25.4% 1.08% −0.84
GPCR Structure Therapeutics Inc. Reduce -34.3% 0.95% −0.82
KYMR Kymera Therapeutics Inc. Reduce -7.9% 6.83% −0.52
FULC Fulcrum Therapeutics Inc. Sold out 0.00% −0.50
WVE Wave Life Sciences Ltd. Sold out 0.00% −0.49
QURE Uniqure NV Sold out 0.00% −0.45
IRON Disc Medicine Inc. Reduce -10.1% 1.32% −0.43
RCUS Arcus Biosciences Inc. Reduce -19.5% 1.51% −0.29
BCYC Bicycle Therapeutics PLC-ADR Sold out 0.00% −0.20
TSLA Tesla Inc. Reduce -83.7% 0.03% −0.19
DYN Dyne Therapeutics Inc. Reduce -4.5% 0.96% −0.16
MSFT Microsoft Corp. Reduce -9.4% 0.28% −0.14
NBP Novabridge Biosciences Reduce -33.2% 0.08% −0.13
AMZN Amazon.com Inc. Reduce -30.3% 0.16% −0.11
WK Workiva Inc. Reduce -51.4% 0.04% −0.11
CRWD CrowdStrike Holdings Inc. Class A Reduce -56.6% 0.15% −0.09
FPS Forgent Power Solutions Class A Sold out 0.00% −0.08
MU Micron Technology Inc. Sold out 0.00% −0.06
AS Amer Sports Inc. Sold out 0.00% −0.05
SEPN Septerna Inc. Reduce -5.0% 1.29% −0.04
NBIS Nebius Group NV Reduce -54.2% 0.29% −0.04
PRMB Primo Brands Corp. Sold out 0.00% −0.03
TBLA Taboola.com Ltd. Reduce -15.5% 0.85% −0.00
FROG Jfrog Ltd. Reduce -25.9% 0.18% +0.01
DDOG Datadog Inc. Class A Reduce -26.3% 0.21% +0.03
BCAX Bicara Therapeutics Inc. Reduce -3.5% 3.38% +0.18
RVMD Revolution Medicines Inc. Reduce -19.0% 3.42% +0.43

Portfolio Buys Q1 2026 → Q2 2026
PBLS Parabilis Medicines Inc. New 1.66% +1.66
ABVX Abivax SA-ADR New 1.56% +1.56
COAG Hemab Therapeutics Holdings New 1.56% +1.56
MANE Veradermics Inc. Add +10.0% 4.13% +1.50
RLAY Relay Therapeutics Inc. New 1.39% +1.39
ELVN Enliven Therapeutics Inc. Add +137.8% 1.83% +1.02
KLRA Kailera Therapeutics Inc. New 0.99% +0.99
DFTX Definium Therapeutics Inc. Add +54.4% 1.36% +0.87
RYTM Rhythm Pharmaceuticals Inc. Add +56.6% 2.56% +0.81
COF Capital One Financial Corp. New 0.70% +0.70
TNGX Tango Therapeutics Inc. Add +9.2% 3.92% +0.64
SYRE Spyre Therapeutics Inc. Add +18.3% 1.75% +0.60
ORKA Oruka Therapeutics Inc. New 0.48% +0.48
SPTX Seaport Therapeutics Inc. New 0.48% +0.48
TYRA Tyra Biosciences Inc. New 0.47% +0.47
ABSI Absci Corp. Add +37.5% 0.58% +0.43
SLN Silence Therapeutics PLC-ADR Add +13.7% 0.74% +0.31
TSHA Taysha Gene Therapies Inc. Add +11.5% 1.36% +0.27
CGEM Cullinan Therapeutics Inc. Add +58.7% 0.70% +0.23
ADAG Adagene Inc.-ADR New 0.23% +0.23
SION Sionna Therapeutics Inc. Add +103.5% 0.55% +0.21
CYTK Cytokinetics Inc. Add +23.6% 1.31% +0.19
OCS Oculis Holding AG New 0.18% +0.18
DSGN Design Therapeutics Inc. New 0.15% +0.15
GOOGL Alphabet Inc. Class A Add +37.0% 0.65% +0.13
IREN Iren Ltd. Add +306.0% 0.16% +0.12
ELOX Eloxx Pharmaceuticals Inc. New 0.11% +0.11
BABA Alibaba Group Holding-SP ADR New 0.10% +0.10
OUST Ouster Inc. New 0.09% +0.09
PALI Palisade Bio Inc. New 0.08% +0.08
ODTX Odyssey Therapeutics Inc. New 0.08% +0.08
AMLX Amylyx Pharmaceuticals Inc. Add +20.4% 0.54% +0.07
AVGO Broadcom Inc. Add +66.7% 0.19% +0.06
ZTS Zoetis Inc. New 0.05% +0.05
AEVA Aeva Technologies Inc. Add +32.2% 0.08% +0.04
TSM Taiwan Semiconductor-SP ADR Add +5.9% 0.43% +0.04
NFLX Netflix Inc. New 0.04% +0.04
QNT Quantinuum Inc. Class A New 0.03% +0.03
ARWR Arrowhead Pharmaceuticals Inc. Add +6.2% 2.84% +0.03
ENTX Entera Bio Ltd. New 0.03% +0.03
LITE Lumentum Holdings Inc. New 0.02% +0.02
WHWK Whitehawk Therapeutics Inc. Add +12.3% 0.22% +0.02
GTLB Gitlab Inc. Class A Add +25.0% 0.08% +0.02
MNDY Monday.com Ltd. Add +70.0% 0.06% +0.01
FOXA Fox Corp. Class A New 0.01% +0.01
T AT&T Inc. New 0.01% +0.01
DT Dynatrace Inc. Add +3.3% 0.14% −0.02
NVDA Nvidia Corp. Add +6.6% 0.39% −0.04
NOW ServiceNow Inc. Add +14.8% 0.20% −0.05
IVVD Invivyd Inc. Add +25.0% 0.09% −0.06

Options Activity Q1 2026 → Q2 2026
MSFT Microsoft Corp. call New 24,000 $9.0M
AAPL Apple Inc. call New 23,000 $6.7M

Calls and puts are listed by the shares they cover; their value is not part of the stock holdings above.

All Filings

QuarterPositions13F Reported ValueTop Holdings
Q2 2026 115$4.9BSRRK, KYMR, ERAS, MANE, TNGX
Q1 2026 100$3.6BSRRK, KYMR, ERAS, EWTX, ONC
Q4 2025 113$3.4BSRRK, KYMR, ONC, EWTX, RVMD
Q3 2025 115$2.6BSRRK, KYMR, ONC, ARWR, BCAX
Q2 2025 110$1.9BSRRK, KYMR, ONC, IRON, CRNX
Q1 2025Amended 116$1.8BSRRK, ONC, KYMR, BPMC, CRNX
Q4 2024 117$2.3BSRRK, ONC, KYMR, APLS, CRNX
Q3 2024 109$2.0BKYMR, ONC, SRRK, BCAX, ARGX