Siren, L.L.C.
In its 13F for Q1 2026 (holdings as of March 31, 2026, filed May 14, 2026), Siren, L.L.C. reported 100 stock positions worth $3.6 billion. Its top holding was Scholar Rock (SRRK) at 14.8% of the portfolio, followed by Kymera Therapeutics (KYMR, 7.4%) and Erasca (ERAS, 5.0%). Compared with Q4 2025, it opened 18 new positions, sold out of 31, added to 36 and reduced 18. The biggest buy was Erasca (ERAS, shares +28%) and the biggest sale an exit from Apellis Pharmaceuticals (APLS).
- Most Recent 13F
- Q2 2026
- Location
- New York, NY
- CIK
- 0002005245
- Portfolio Value
- $3.6B (Q1 2026)
- SEC Filing
- 0002005245-26-000006 ↗ filed May 14, 2026
Holdings Value
Holdings 100 stocks · $3.6B
| SRRK Scholar Rock Holding Corp. | 14.75% | 10,825,013 | $532.2M | No change |
| KYMR Kymera Therapeutics Inc. | 7.36% | 3,186,830 | $265.4M | Reduce -3.0% |
| ERAS Erasca Inc. | 5.04% | 11,244,246 | $181.9M | Add +28.4% |
| EWTX Edgewise Therapeutics Inc. | 3.87% | 4,430,263 | $139.6M | Reduce -2.2% |
| ONC Beone Medicines Ltd.-ADR | 3.83% | 465,000 | $138.1M | Reduce -7.0% |
| TNGX Tango Therapeutics Inc. | 3.28% | 5,657,105 | $118.3M | Reduce -30.7% |
| BCAX Bicara Therapeutics Inc. | 3.20% | 5,802,970 | $115.4M | Add +11.2% |
| RVMD Revolution Medicines Inc. | 3.00% | 1,110,980 | $108.0M | Reduce -16.8% |
| ARWR Arrowhead Pharmaceuticals Inc. | 2.81% | 1,615,476 | $101.3M | Add +7.7% |
| MANE Veradermics Inc. | 2.64% | 1,505,374 | $95.1M | New |
| XENE Xenon Pharmaceuticals Inc. | 2.13% | 1,318,564 | $76.7M | Add +62.2% |
| OLMA Olema Pharmaceuticals Inc. | 1.97% | 4,756,949 | $70.9M | Add +44.1% |
| CRNX Crinetics Pharmaceuticals Inc. | 1.92% | 1,903,636 | $69.1M | Add +26.3% |
| LXRX Lexicon Pharmaceuticals Inc. | 1.92% | 44,303,518 | $69.1M | Add +13.8% |
| COGT Cogent Biosciences Inc. | 1.82% | 1,709,279 | $65.8M | Add +4.9% |
| STOK Stoke Therapeutics Inc. | 1.80% | 1,995,347 | $65.0M | Reduce -11.2% |
| RCUS Arcus Biosciences Inc. | 1.80% | 3,007,077 | $65.0M | No change |
| GPCR Structure Therapeutics Inc. | 1.78% | 1,328,698 | $64.0M | Add +23.2% |
| IRON Disc Medicine Inc. | 1.75% | 988,401 | $63.2M | No change |
| RYTM Rhythm Pharmaceuticals Inc. | 1.75% | 725,511 | $63.1M | Add +45.1% |
| SLDB Solid Biosciences Inc. | 1.53% | 7,690,405 | $55.4M | No change |
| SEPN Septerna Inc. | 1.33% | 2,000,000 | $48.1M | No change |
| CNTA Centessa Pharmaceuticals Ltd. | 1.16% | 1,053,464 | $41.8M | Reduce -73.8% |
| SYRE Spyre Therapeutics Inc. | 1.14% | 818,598 | $41.3M | No change |
| CYTK Cytokinetics Inc. | 1.12% | 613,952 | $40.5M | New |
| DYN Dyne Therapeutics Inc. | 1.12% | 2,229,125 | $40.4M | Reduce -36.4% |
| TSHA Taysha Gene Therapies Inc. | 1.09% | 8,829,913 | $39.5M | Reduce -12.8% |
| DBVT DBV Technologies SA-Spon ADR | 1.08% | 1,857,362 | $38.8M | No change |
| ORIC Oric Pharmaceuticals Inc. | 1.05% | 2,998,192 | $38.0M | Add +197.6% |
| ENGN Engene Holdings Inc. | 0.99% | 5,253,159 | $35.8M | Add +57.5% |
| PVLA Palvella Therapeutics Inc. | 0.89% | 257,485 | $32.1M | Add +243.3% |
| TBLA Taboola.com Ltd. | 0.86% | 9,969,495 | $30.9M | No change |
| ELVN Enliven Therapeutics Inc. | 0.81% | 746,226 | $29.3M | New |
| DNLI Denali Therapeutics Inc. | 0.74% | 1,396,513 | $26.8M | No change |
| RELY Remitly Global Inc. | 0.67% | 1,543,271 | $24.2M | Reduce -4.6% |
| DMRA Damora Therapeutics Inc. | 0.65% | 900,000 | $23.3M | New |
| ZURA Zura Bio Ltd. | 0.62% | 3,734,866 | $22.2M | Add +187.3% |
| ANNX Annexon Inc. | 0.61% | 3,958,646 | $21.9M | New |
| TRVI Trevi Therapeutics Inc. | 0.59% | 1,786,867 | $21.3M | Reduce -21.9% |
| RAPP Rapport Therapeutics Inc. | 0.56% | 641,469 | $20.1M | Reduce -9.5% |
| GOOGL Alphabet Inc. Class A | 0.52% | 65,703 | $18.9M | Add +217.4% |
| FULC Fulcrum Therapeutics Inc. | 0.50% | 2,350,000 | $18.0M | Add +20.5% |
| WVE Wave Life Sciences Ltd. | 0.49% | 2,450,000 | $17.8M | No change |
| DFTX Definium Therapeutics Inc. | 0.48% | 919,493 | $17.4M | Add +14.9% |
| AMLX Amylyx Pharmaceuticals Inc. | 0.47% | 1,230,000 | $17.1M | New |
| CGEM Cullinan Therapeutics Inc. | 0.47% | 1,193,410 | $17.0M | No change |
| NMRA Neumora Therapeutics Inc. | 0.46% | 8,497,822 | $16.6M | Add +35.1% |
| QURE Uniqure NV | 0.45% | 1,000,000 | $16.4M | New |
| CTMX Cytomx Therapeutics Inc. | 0.45% | 3,457,711 | $16.3M | New |
| NVDA Nvidia Corp. | 0.43% | 89,085 | $15.5M | Add +137.7% |
| SLN Silence Therapeutics PLC-ADR | 0.43% | 2,911,438 | $15.3M | No change |
| MSFT Microsoft Corp. | 0.42% | 41,380 | $15.3M | Add +175.9% |
| MNPR Monopar Therapeutics Inc. | 0.41% | 270,118 | $14.8M | Add +27.2% |
| TSM Taiwan Semiconductor-SP ADR | 0.40% | 42,200 | $14.3M | Add +52.4% |
| SION Sionna Therapeutics Inc. | 0.33% | 300,000 | $12.0M | No change |
| NBIS Nebius Group NV | 0.33% | 113,614 | $11.8M | Add +49.1% |
| RZLT Rezolute Inc. | 0.28% | 3,328,287 | $10.2M | New |
| IKT Inhibikase Therapeutics Inc. | 0.27% | 5,850,000 | $9.8M | No change |
| AMZN Amazon.com Inc. | 0.27% | 46,641 | $9.7M | Reduce -9.4% |
| GENB Generate Biomedicines Inc. | 0.26% | 736,104 | $9.2M | New |
| MPLT Maplight Therapeutics Inc. | 0.25% | 450,000 | $9.1M | No change |
| NOW ServiceNow Inc. | 0.25% | 87,090 | $9.1M | Add +144.4% |
| CRWD CrowdStrike Holdings Inc. Class A | 0.25% | 23,070 | $9.0M | Add +39.8% |
| PDD PDD Holdings Inc. | 0.24% | 83,401 | $8.5M | Add +31.6% |
| TSLA Tesla Inc. | 0.22% | 21,500 | $8.0M | Add +1333.3% |
| NBP Novabridge Biosciences | 0.20% | 3,000,000 | $7.4M | No change |
| BCYC Bicycle Therapeutics PLC-ADR | 0.20% | 1,560,882 | $7.2M | Reduce -22.4% |
| WHWK Whitehawk Therapeutics Inc. | 0.20% | 2,082,000 | $7.2M | No change |
| TENX Tenax Therapeutics Inc. | 0.19% | 427,141 | $6.8M | No change |
| VTVT VTV Therapeutics Inc. Class A | 0.18% | 163,000 | $6.5M | No change |
| DDOG Datadog Inc. Class A | 0.18% | 54,300 | $6.4M | Add +49.1% |
| FROG Jfrog Ltd. | 0.17% | 128,816 | $6.0M | Add +37.6% |
| DT Dynatrace Inc. | 0.15% | 150,000 | $5.5M | Add +30.2% |
| WK Workiva Inc. | 0.15% | 92,500 | $5.5M | Add +16.9% |
| ABSI Absci Corp. | 0.15% | 1,800,000 | $5.4M | New |
| IVVD Invivyd Inc. | 0.14% | 4,000,000 | $5.2M | No change |
| MSLE Satellos Bioscience Inc. | 0.14% | 892,074 | $5.0M | New |
| IONQ Ionq Inc. | 0.14% | 170,000 | $4.9M | No change |
| AVGO Broadcom Inc. | 0.13% | 15,000 | $4.6M | Add +114.3% |
| AGMB Agomab Therapeutics NV | 0.12% | 411,250 | $4.3M | New |
| CLBT Cellebrite Di Ltd. | 0.12% | 311,544 | $4.3M | Add +107.7% |
| SEER Seer Inc. | 0.11% | 2,458,673 | $4.1M | Reduce -38.5% |
| KRRO Korro Bio Inc. | 0.11% | 347,718 | $3.9M | No change |
| AGEN Agenus Inc. | 0.10% | 1,064,250 | $3.6M | No change |
| FHTX Foghorn Therapeutics Inc. | 0.10% | 720,720 | $3.4M | No change |
| FPS Forgent Power Solutions Class A | 0.08% | 100,000 | $2.9M | New |
| KLRS Kalaris Therapeutics Inc. | 0.07% | 435,798 | $2.5M | No change |
| GTLB Gitlab Inc. Class A | 0.06% | 100,000 | $2.2M | Add +1.0% |
| MU Micron Technology Inc. | 0.06% | 6,000 | $2.0M | New |
| MNDY Monday.com Ltd. | 0.05% | 25,000 | $1.7M | Add +47.1% |
| GOSS Gossamer Bio Inc. | 0.05% | 5,208,968 | $1.7M | No change |
| AS Amer Sports Inc. | 0.05% | 50,000 | $1.6M | New |
| BEKE Ke Holdings Inc.-ADR filed as KE HLDGS INC | 0.04% | 100,000 | $1.5M | Reduce -31.0% |
| IREN Iren Ltd. filed as IREN LIMITED | 0.04% | 43,100 | $1.5M | No change |
| RANI Rani Therapeutics Holdings Class A | 0.04% | 2,000,000 | $1.5M | No change |
| AEVA Aeva Technologies Inc. | 0.04% | 110,000 | $1.4M | New |
| MDLN Medline Inc. Class A | 0.03% | 25,000 | $1.1M | Reduce -66.7% |
| FIG Figma Inc. Class A | 0.03% | 50,000 | $1.1M | Add +100.0% |
| PRMB Primo Brands Corp. | 0.03% | 50,000 | $942K | Reduce -33.3% |
| NU Nu Holdings Ltd./Cayman Isl-A filed as NU HLDGS LTD | 0.01% | 25,000 | $359K | New |
Portfolio Sells Q4 2025 → Q1 2026
| APLS Apellis Pharmaceuticals Inc. | Sold out | 0.00% | −1.93 |
| CNTA Centessa Pharmaceuticals Ltd. | Reduce -73.8% | 1.16% | −1.84 |
| ASND Ascendis Pharma A/S | Sold out | 0.00% | −1.50 |
| RAPT Rapt Therapeutics Inc. | Sold out | 0.00% | −1.39 |
| ZYME Zymeworks Inc. | Sold out | 0.00% | −1.32 |
| DYN Dyne Therapeutics Inc. | Reduce -36.4% | 1.12% | −0.92 |
| MLYS Mineralys Therapeutics Inc. | Sold out | 0.00% | −0.76 |
| ONC Beone Medicines Ltd.-ADR | Reduce -7.0% | 3.83% | −0.70 |
| TSHA Taysha Gene Therapies Inc. | Reduce -12.8% | 1.09% | −0.57 |
| IHS Ihs Holding Ltd. | Sold out | 0.00% | −0.52 |
| UPB Upstream Bio Inc. | Sold out | 0.00% | −0.48 |
| STOK Stoke Therapeutics Inc. | Reduce -11.2% | 1.80% | −0.33 |
| BNTC Benitec Biopharma Inc. | Sold out | 0.00% | −0.31 |
| KYMR Kymera Therapeutics Inc. | Reduce -3.0% | 7.36% | −0.27 |
| TRVI Trevi Therapeutics Inc. | Reduce -21.9% | 0.59% | −0.26 |
| BCYC Bicycle Therapeutics PLC-ADR | Reduce -22.4% | 0.20% | −0.22 |
| LXEO Lexeo Therapeutics Inc. | Sold out | 0.00% | −0.21 |
| CRM Salesforce Inc. | Sold out | 0.00% | −0.21 |
| CMPS Compass Pathways PLC | Sold out | 0.00% | −0.21 |
| BLLN Billiontoone Inc. Class A | Sold out | 0.00% | −0.20 |
| SVRA Savara Inc. | Sold out | 0.00% | −0.18 |
| XFOR X4 Pharmaceuticals Inc. | Sold out | 0.00% | −0.18 |
| RVMD Revolution Medicines Inc. | Reduce -16.8% | 3.00% | −0.18 |
| ALMS Alumis Inc. | Sold out | 0.00% | −0.15 |
| META Meta Platforms Inc. Class A | Sold out | 0.00% | −0.14 |
| PEPG Pepgen Inc. | Sold out | 0.00% | −0.14 |
| SGMT Sagimet Biosciences Inc. Class A | Sold out | 0.00% | −0.13 |
| ADBE Adobe Inc. | Sold out | 0.00% | −0.13 |
| SEER Seer Inc. | Reduce -38.5% | 0.11% | −0.10 |
| EDU New Oriental Educatio-SP ADR | Sold out | 0.00% | −0.10 |
| AMZN Amazon.com Inc. | Reduce -9.4% | 0.27% | −0.09 |
| RAPP Rapport Therapeutics Inc. | Reduce -9.5% | 0.56% | −0.08 |
| ZS Zscaler Inc. | Sold out | 0.00% | −0.08 |
| BDTX Black Diamond Therapeutics I | Sold out | 0.00% | −0.08 |
| QCOM Qualcomm Inc. | Sold out | 0.00% | −0.07 |
| ARM Arm Holdings PLC-ADR | Sold out | 0.00% | −0.07 |
| TIL Instil Bio Inc. | Sold out | 0.00% | −0.07 |
| MDLN Medline Inc. Class A | Reduce -66.7% | 0.03% | −0.06 |
| PANW Palo Alto Networks Inc. | Sold out | 0.00% | −0.06 |
| CRWV Coreweave Inc. Class A | Sold out | 0.00% | −0.06 |
| VRNS Varonis Systems Inc. | Sold out | 0.00% | −0.04 |
| GBIO Generation Bio Co. | Sold out | 0.00% | −0.03 |
| BEKE Ke Holdings Inc.-ADR | Reduce -31.0% | 0.04% | −0.03 |
| PRMB Primo Brands Corp. | Reduce -33.3% | 0.03% | −0.01 |
| CRBU Caribou Biosciences Inc. | Sold out | 0.00% | −0.01 |
| CYCLERION THERAPEUTICS INC | Sold out | 0.00% | −0.00 |
| RELY Remitly Global Inc. | Reduce -4.6% | 0.67% | +0.00 |
| EWTX Edgewise Therapeutics Inc. | Reduce -2.2% | 3.87% | +0.52 |
| TNGX Tango Therapeutics Inc. | Reduce -30.7% | 3.28% | +1.12 |
Portfolio Buys Q4 2025 → Q1 2026
| ERAS Erasca Inc. | Add +28.4% | 5.04% | +4.07 |
| MANE Veradermics Inc. | New | 2.64% | +2.64 |
| CYTK Cytokinetics Inc. | New | 1.12% | +1.12 |
| XENE Xenon Pharmaceuticals Inc. | Add +62.2% | 2.13% | +1.04 |
| ELVN Enliven Therapeutics Inc. | New | 0.81% | +0.81 |
| ORIC Oric Pharmaceuticals Inc. | Add +197.6% | 1.05% | +0.81 |
| PVLA Palvella Therapeutics Inc. | Add +243.3% | 0.89% | +0.66 |
| DMRA Damora Therapeutics Inc. | New | 0.65% | +0.65 |
| ANNX Annexon Inc. | New | 0.61% | +0.61 |
| LXRX Lexicon Pharmaceuticals Inc. | Add +13.8% | 1.92% | +0.58 |
| BCAX Bicara Therapeutics Inc. | Add +11.2% | 3.20% | +0.58 |
| AMLX Amylyx Pharmaceuticals Inc. | New | 0.47% | +0.47 |
| QURE Uniqure NV | New | 0.45% | +0.45 |
| CTMX Cytomx Therapeutics Inc. | New | 0.45% | +0.45 |
| ZURA Zura Bio Ltd. | Add +187.3% | 0.62% | +0.41 |
| GOOGL Alphabet Inc. Class A | Add +217.4% | 0.52% | +0.33 |
| RZLT Rezolute Inc. | New | 0.28% | +0.28 |
| GENB Generate Biomedicines Inc. | New | 0.26% | +0.26 |
| NVDA Nvidia Corp. | Add +137.7% | 0.43% | +0.22 |
| MSFT Microsoft Corp. | Add +175.9% | 0.42% | +0.21 |
| TSLA Tesla Inc. | Add +1333.3% | 0.22% | +0.20 |
| DFTX Definium Therapeutics Inc. | Add +14.9% | 0.48% | +0.16 |
| RYTM Rhythm Pharmaceuticals Inc. | Add +45.1% | 1.75% | +0.15 |
| ABSI Absci Corp. | New | 0.15% | +0.15 |
| TSM Taiwan Semiconductor-SP ADR | Add +52.4% | 0.40% | +0.14 |
| MSLE Satellos Bioscience Inc. | New | 0.14% | +0.14 |
| NBIS Nebius Group NV | Add +49.1% | 0.33% | +0.14 |
| NMRA Neumora Therapeutics Inc. | Add +35.1% | 0.46% | +0.12 |
| AGMB Agomab Therapeutics NV | New | 0.12% | +0.12 |
| COGT Cogent Biosciences Inc. | Add +4.9% | 1.82% | +0.10 |
| ENGN Engene Holdings Inc. | Add +57.5% | 0.99% | +0.09 |
| NOW ServiceNow Inc. | Add +144.4% | 0.25% | +0.09 |
| FPS Forgent Power Solutions Class A | New | 0.08% | +0.08 |
| AVGO Broadcom Inc. | Add +114.3% | 0.13% | +0.06 |
| MU Micron Technology Inc. | New | 0.06% | +0.06 |
| AS Amer Sports Inc. | New | 0.05% | +0.05 |
| AEVA Aeva Technologies Inc. | New | 0.04% | +0.04 |
| CLBT Cellebrite Di Ltd. | Add +107.7% | 0.12% | +0.04 |
| DDOG Datadog Inc. Class A | Add +49.1% | 0.18% | +0.03 |
| PDD PDD Holdings Inc. | Add +31.6% | 0.24% | +0.02 |
| CRWD CrowdStrike Holdings Inc. Class A | Add +39.8% | 0.25% | +0.02 |
| NU Nu Holdings Ltd./Cayman Isl-A | New | 0.01% | +0.01 |
| DT Dynatrace Inc. | Add +30.2% | 0.15% | +0.00 |
| FIG Figma Inc. Class A | Add +100.0% | 0.03% | +0.00 |
| MNPR Monopar Therapeutics Inc. | Add +27.2% | 0.41% | −0.00 |
| FROG Jfrog Ltd. | Add +37.6% | 0.17% | −0.01 |
| MNDY Monday.com Ltd. | Add +47.1% | 0.05% | −0.03 |
| WK Workiva Inc. | Add +16.9% | 0.15% | −0.05 |
| GTLB Gitlab Inc. Class A | Add +1.0% | 0.06% | −0.05 |
| FULC Fulcrum Therapeutics Inc. | Add +20.5% | 0.50% | −0.16 |
All Filings
| Quarter | Positions | 13F Reported Value | Top Holdings |
|---|---|---|---|
| Q2 2026 | 115 | $4.9B | SRRK, KYMR, ERAS, MANE, TNGX |
| Q1 2026 | 100 | $3.6B | SRRK, KYMR, ERAS, EWTX, ONC |
| Q4 2025 | 113 | $3.4B | SRRK, KYMR, ONC, EWTX, RVMD |
| Q3 2025 | 115 | $2.6B | SRRK, KYMR, ONC, ARWR, BCAX |
| Q2 2025 | 110 | $1.9B | SRRK, KYMR, ONC, IRON, CRNX |
| Q1 2025Amended | 116 | $1.8B | SRRK, ONC, KYMR, BPMC, CRNX |
| Q4 2024 | 117 | $2.3B | SRRK, ONC, KYMR, APLS, CRNX |
| Q3 2024 | 109 | $2.0B | KYMR, ONC, SRRK, BCAX, ARGX |