Siren, L.L.C. 13F holdings
Siren, L.L.C. reported 115 positions with a total reported value of $4.9B as of 2026-06-30, in its 13F for Q2 2026, filed 2026-08-13. Top holdings by reported value: SRRK Scholar Rock Holding Corp (10.7%), KYMR Kymera Therapeutics Inc (6.8%), ERAS Erasca Inc (4.2%), MANE Veradermics Inc (4.1%), TNGX Tango Therapeutics Inc (3.9%). Against 2026-03-31 it opened 24 new positions and exited 9. Next 13F due by 2026-11-14, the legal deadline 45 days after the quarter ending 2026-09-30.
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Top holdings
25 largest of 115 positions · reported value as of 2026-06-30
| Holding | Shares | Reported value | % of portfolio |
|---|---|---|---|
| SRRK Scholar Rock Holding Corp | 9,575,013 | $526.6M | 10.7% |
| KYMR Kymera Therapeutics Inc | 2,935,830 | $336.7M | 6.8% |
| ERAS Erasca Inc | 11,397,781 | $208.8M | 4.2% |
| MANE Veradermics Inc | 1,655,374 | $203.5M | 4.1% |
| TNGX Tango Therapeutics Inc | 6,179,364 | $193.2M | 3.9% |
| RVMD Revolution Medicines Inc | 900,000 | $168.6M | 3.4% |
| BCAX Bicara Therapeutics Inc | 5,602,970 | $166.4M | 3.4% |
| ARWR Arrowhead Pharmaceuticals Inc | 1,715,476 | $139.8M | 2.8% |
| ONC BeOne Medicines AG | 465,000 | $132.5M | 2.7% |
| EWTX Edgewise Therapeutics Inc | 3,184,629 | $129.4M | 2.6% |
| RYTM Rhythm Pharmaceuticals Inc | 1,136,275 | $126.2M | 2.6% |
| LXRX Lexicon Pharmaceuticals Inc | 44,303,518 | $106.3M | 2.2% |
| ELVN Enliven Therapeutics Inc | 1,774,411 | $90.1M | 1.8% |
| SYRE Spyre Therapeutics Inc | 968,598 | $86.0M | 1.7% |
| PBLS Parabilis Medicines Inc | 2,992,259 | $81.9M | 1.7% |
| XENE Xenon Pharmaceuticals Inc | 1,318,564 | $79.6M | 1.6% |
| SLDB Solid Biosciences Inc | 7,690,405 | $76.8M | 1.6% |
| ABVX Abivax SA | 576,000 | $76.8M | 1.6% |
| COAG Hemab Therapeutics Holdings Inc | 2,086,834 | $76.6M | 1.6% |
| RCUS Arcus Biosciences Inc | 2,420,430 | $74.6M | 1.5% |
| COGT Cogent Biosciences Inc | 1,859,279 | $72.0M | 1.5% |
| RLAY Relay Therapeutics Inc | 3,650,000 | $68.3M | 1.4% |
| TSHA Taysha Gene Therapies Inc | 9,846,579 | $67.1M | 1.4% |
| DFTX Definium Therapeutics Inc | 1,419,493 | $66.8M | 1.4% |
| STOK Stoke Therapeutics Inc | 1,995,347 | $65.3M | 1.3% |
SEC FORM 13F · Q2 2026 · VALUES AS REPORTED, NOT PRICES
New positions this quarter
Held at 2026-06-30, not at 2026-03-31 · 24 in all · reported value as of 2026-06-30
| Holding | Shares | Reported value | % of portfolio |
|---|---|---|---|
| PBLS Parabilis Medicines Inc | 2,992,259 | $81.9M | 1.7% |
| ABVX Abivax SA | 576,000 | $76.8M | 1.6% |
| COAG Hemab Therapeutics Holdings Inc | 2,086,834 | $76.6M | 1.6% |
| RLAY Relay Therapeutics Inc | 3,650,000 | $68.3M | 1.4% |
| KLRA Kailera Therapeutics Inc | 2,214,286 | $48.8M | 1.0% |
| COF Capital One Finl Corp | 171,615 | $34.4M | 0.7% |
| ORKA Oruka Therapeutics Inc | 250,000 | $23.8M | 0.5% |
| SPTX Seaport Therapeutics Inc | 1,095,316 | $23.8M | 0.5% |
| TYRA Tyra Biosciences Inc | 725,000 | $23.2M | 0.5% |
| ADAG Adagene Inc | 2,666,666 | $11.2M | 0.2% |
| OCS Oculis Holding AG | 625,000 | $8.7M | 0.2% |
| DSGN Design Therapeutics Inc | 523,212 | $7.6M | 0.2% |
| ELOX Eloxx Pharmaceuticals Inc | 400,000 | $5.6M | 0.1% |
| BABA Alibaba Group Holding Ltd | 50,000 | $4.8M | <0.1% |
| OUST Ouster Inc | 67,500 | $4.2M | <0.1% |
| PALI Palisade Bio Inc | 2,000,000 | $4.2M | <0.1% |
| ODTX Odyssey Therapeutics Inc | 200,000 | $3.7M | <0.1% |
| ZTS Zoetis Inc | 35,000 | $2.5M | <0.1% |
| NFLX Netflix Inc | 25,000 | $1.8M | <0.1% |
| QNT Quantinuum Inc | 20,000 | $1.6M | <0.1% |
| ENTX Entera Bio Ltd | 736,457 | $1.3M | <0.1% |
| LITE Lumentum Holdings Inc | 1,055 | $905.3K | <0.1% |
| FOXA Fox Corp | 10,000 | $521.6K | <0.1% |
| T AT&T Inc | 25,000 | $517.5K | <0.1% |
Sold out
Held at 2026-03-31, gone by 2026-06-30 · 9 in all · reported value as of 2026-03-31
| Holding | Shares 2026-03-31 | Reported value | % of portfolio then |
|---|---|---|---|
| Centessa Pharmaceuticals PLC | 1,053,464 | $41.8M | 1.2% |
| FULC Fulcrum Therapeutics Inc | 2,350,000 | $18.0M | 0.5% |
| WVE WAVE Life Sciences Ltd | 2,450,000 | $17.8M | 0.5% |
| QURE Uniqure NV | 1,000,000 | $16.4M | 0.5% |
| BCYC Bicycle Therapeutics PLC | 1,560,882 | $7.2M | 0.2% |
| FPS Forgent Power Solutions, Inc | 100,000 | $2.9M | <0.1% |
| MU Micron Technology Inc | 6,000 | $2.0M | <0.1% |
| AS Amer Sports Inc | 50,000 | $1.6M | <0.1% |
| PRMB Primo Brands Corp | 50,000 | $941.5K | <0.1% |
Biggest increases and decreases
Positions held at both quarter ends, by change in shares · reported value as of 2026-06-30
Increases
| Holding | Shares 2026-03-31 | Shares 2026-06-30 | Change | Reported value |
|---|---|---|---|---|
| ELVN Enliven Therapeutics Inc | 746,226 | 1,774,411 | +137.8% | $90.1M |
| RYTM Rhythm Pharmaceuticals Inc | 725,511 | 1,136,275 | +56.6% | $126.2M |
| DFTX Definium Therapeutics Inc | 919,493 | 1,419,493 | +54.4% | $66.8M |
| MANE Veradermics Inc | 1,505,374 | 1,655,374 | +10.0% | $203.5M |
| TNGX Tango Therapeutics Inc | 5,657,105 | 6,179,364 | +9.2% | $193.2M |
| SION Sionna Therapeutics Inc | 300,000 | 610,515 | +103.5% | $26.9M |
| SYRE Spyre Therapeutics Inc | 818,598 | 968,598 | +18.3% | $86.0M |
| CGEM Cullinan Therapeutics Inc | 1,193,410 | 1,893,410 | +58.7% | $34.5M |
| CYTK Cytokinetics Inc | 613,952 | 758,952 | +23.6% | $64.7M |
| GOOGL Alphabet Inc | 65,703 | 90,000 | +37.0% | $32.2M |
| ARWR Arrowhead Pharmaceuticals Inc | 1,615,476 | 1,715,476 | +6.2% | $139.8M |
| ABSI Absci Corp | 1,800,000 | 2,474,764 | +37.5% | $28.7M |
Decreases
| Holding | Shares 2026-03-31 | Shares 2026-06-30 | Change | Reported value |
|---|---|---|---|---|
| SRRK Scholar Rock Holding Corp | 10,825,013 | 9,575,013 | -11.5% | $526.6M |
| EWTX Edgewise Therapeutics Inc | 4,430,263 | 3,184,629 | -28.1% | $129.4M |
| RVMD Revolution Medicines Inc | 1,110,980 | 900,000 | -19.0% | $168.6M |
| KYMR Kymera Therapeutics Inc | 3,186,830 | 2,935,830 | -7.9% | $336.7M |
| GPCR Structure Therapeutics Inc | 1,328,698 | 872,967 | -34.3% | $46.9M |
| RCUS Arcus Biosciences Inc | 3,007,077 | 2,420,430 | -19.5% | $74.6M |
| CRNX Crinetics Pharmaceuticals Inc | 1,903,636 | 1,420,788 | -25.4% | $53.2M |
| NBIS Nebius Group NV | 113,614 | 52,000 | -54.2% | $14.4M |
| CRWD CrowdStrike Holdings Inc | 23,070 | 10,000 | -56.7% | $7.6M |
| TBLA Taboola.com Ltd | 9,969,495 | 8,423,410 | -15.5% | $42.1M |
| TSLA Tesla Inc | 21,500 | 3,500 | -83.7% | $1.5M |
| IRON Disc Medicine Inc | 988,401 | 888,401 | -10.1% | $65.0M |
CIK 2005245 · 13F FILINGS ON EDGAR · INFORMATIONAL ONLY
