Siren, L.L.C.
Siren, L.L.C. reported 115 US-listed holdings worth $4.93 billion in its 13F for the quarter ended 30 June 2026, filed 13 August 2026. Its largest: Scholar Rock Holding Corporation (10.7%), Kymera Therapeutics Inc. (6.8%) and Erasca Inc. (4.2%). Against the quarter before, it opened 25 positions, added to 31, trimmed 21 and sold out of 10.
Reported holdings$4.93B+36.5% on Q1 2026
Positions115+15 on Q1 2026
The largest ten44.8%of its reported holdings
Latest 13FQ2 2026filed 13 August 2026
Added toHeldTrimmed
The 14 largest of its 115 positions, each sized by its share of the reported holdings, coloured by the change in shares against Q1 2026.
What the fund reported holding at each quarter's end; hover a bar for the number of positions
What it did on the quarter
Opened 25Added 31Held 38Trimmed 21Sold out 10
Its positions against its 13F for the quarter to 31 March 2026; a change under 0.1% of a position counts as held
Opened 25
- Parabilis Medicines Inc. Com PBLS$81.9 million
- Abivax SA ABVX$76.8 million
- Hemab Therapeutics Hldgs Inc. COAG$76.6 million
- Relay Therapeutics Inc. RLAY$68.3 million
- Kailera Therapeutics Inc. KLRA$48.8 million
- Capital One Financial Corp. COF$34.4 million
- Oruka Therapeutics Inc. ORKA$23.8 million
- Seaport Therapeutics Inc. SPTX$23.8 million
and 17 more in the table below
Added to 31
- Enliven Therapeutics Inc. ELVN+1.0 million shares · +138%
- Rhythm Pharmaceuticals Inc. RYTM+410,764 shares · +57%
- Definium Therapeutics Inc. DFTX+500,000 shares · +54%
- Veradermics Inc MANE+150,000 shares · +10%
- Tango Therapeutics Inc. TNGX+522,259 shares · +9%
- Sionna Therapeutics Inc SION+310,515 shares · +104%
- Spyre Therapeutics Inc. SYRE+150,000 shares · +18%
- Cullinan Therapeutics Inc. CGEM+700,000 shares · +59%
and 23 more in the table below
Trimmed 21
- Scholar Rock Holding Corporation SRRK-1.2 million shares · -12%
- Edgewise Therapeutics Inc. EWTX-1.2 million shares · -28%
- Revolution Medicines, Inc. RVMD-210,980 shares · -19%
- Kymera Therapeutics Inc. KYMR-251,000 shares · -8%
- Structure Therapeutics Inc. GPCR-455,731 shares · -34%
- Arcus Biosciences, Inc. RCUS-586,647 shares · -20%
- Crinetics Pharmaceuticals in CRNX-482,848 shares · -25%
- Yandex N V NBIS-61,614 shares · -54%
and 13 more in the table below
Sold out of 10
- Centessa Pharmaceuticals PLC CNTA$41.8 million last quarter
- Engene Holdings Inc. ENGN$35.8 million last quarter
- Fulcrum Therapeutics Inc. FULC$18.0 million last quarter
- Wave Life Sciences Ltd WVE$17.8 million last quarter
- Uniqure NV QURE$16.4 million last quarter
- Bicycle Therapeutics PLC BCYC$7.2 million last quarter
- Forgent Power Solutions Inc FPS$2.9 million last quarter
- Micron Technology Inc. MU$2.0 million last quarter
What it holds
| Company | Shares | Value | Of its book | Change in shares |
|---|---|---|---|---|
| Scholar Rock Holding Corporation SRRK | 9,575,013 | $526.6 million | 10.69% | -1,250,000 |
| Kymera Therapeutics Inc. KYMR | 2,935,830 | $336.7 million | 6.83% | -251,000 |
| Erasca Inc. ERAS | 11,397,781 | $208.8 million | 4.24% | +153,535 |
| Veradermics Inc MANE | 1,655,374 | $203.5 million | 4.13% | +150,000 |
| Tango Therapeutics Inc. TNGX | 6,179,364 | $193.2 million | 3.92% | +522,259 |
| Revolution Medicines, Inc. RVMD | 900,000 | $168.6 million | 3.42% | -210,980 |
| Bicara Therapeutics Inc. BCAX | 5,602,970 | $166.4 million | 3.38% | -200,000 |
| Arrowhead Pharmaceuticals, Inc. ARWR | 1,715,476 | $139.8 million | 2.84% | +100,000 |
| Beigene, Ltd ONC | 465,000 | $132.5 million | 2.69% | no change |
| Edgewise Therapeutics Inc. EWTX | 3,184,629 | $129.4 million | 2.63% | -1,245,634 |
| Rhythm Pharmaceuticals Inc. RYTM | 1,136,275 | $126.2 million | 2.56% | +410,764 |
| Lexicon Pharmaceuticals Inc. LXRX | 44,303,518 | $106.3 million | 2.16% | no change |
| Enliven Therapeutics Inc. ELVN | 1,774,411 | $90.1 million | 1.83% | +1,028,185 |
| Spyre Therapeutics Inc. SYRE | 968,598 | $86.0 million | 1.75% | +150,000 |
| Parabilis Medicines Inc. Com PBLS | 2,992,259 | $81.9 million | 1.66% | new |
| Xenon Pharmaceuticals Inc. XENE | 1,318,564 | $79.6 million | 1.62% | no change |
| Solid Biosciences Inc. SLDB | 7,690,405 | $76.8 million | 1.56% | no change |
| Abivax SA ABVX | 576,000 | $76.8 million | 1.56% | new |
| Hemab Therapeutics Hldgs Inc. COAG | 2,086,834 | $76.6 million | 1.56% | new |
| Arcus Biosciences, Inc. RCUS | 2,420,430 | $74.6 million | 1.51% | -586,647 |
| Cogent Biosciences Inc. COGT | 1,859,279 | $72.0 million | 1.46% | +150,000 |
| Relay Therapeutics Inc. RLAY | 3,650,000 | $68.3 million | 1.39% | new |
| Taysha Gene Therapies Inc. TSHA | 9,846,579 | $67.1 million | 1.36% | +1,016,666 |
| Definium Therapeutics Inc. DFTX | 1,419,493 | $66.8 million | 1.36% | +500,000 |
| Stoke Therapeutics Inc. STOK | 1,995,347 | $65.3 million | 1.33% | no change |
| Disc Medicine Inc. IRON | 888,401 | $65.0 million | 1.32% | -100,000 |
| Cytokinetics Inc. CYTK | 758,952 | $64.7 million | 1.31% | +145,000 |
| Septerna Inc. SEPN | 1,900,000 | $63.6 million | 1.29% | -100,000 |
| Olema Pharmaceuticals Inc. OLMA | 4,856,949 | $60.8 million | 1.23% | +100,000 |
| Crinetics Pharmaceuticals in CRNX | 1,420,788 | $53.2 million | 1.08% | -482,848 |
| Kailera Therapeutics Inc. KLRA | 2,214,286 | $48.8 million | 0.99% | new |
| Dyne Therapeutics Inc. DYN | 2,129,125 | $47.3 million | 0.96% | -100,000 |
| Structure Therapeutics Inc. GPCR | 872,967 | $46.9 million | 0.95% | -455,731 |
| Taboola.com Ltd TBLA | 8,423,410 | $42.1 million | 0.86% | -1,546,085 |
| Palvella Therapeutics Inc. Ne PVLA | 257,485 | $39.3 million | 0.80% | no change |
| Silence Therapeutics PLC SLN | 3,311,438 | $36.4 million | 0.74% | +400,000 |
| Denali Therapeutics Inc. DNLI | 1,396,513 | $35.9 million | 0.73% | no change |
| Remitly Global, Inc. RELY | 1,543,271 | $34.6 million | 0.70% | no change |
| Cullinan Therapeutics Inc. CGEM | 1,893,410 | $34.5 million | 0.70% | +700,000 |
| Capital One Financial Corp. COF | 171,615 | $34.4 million | 0.70% | new |
| Trevi Therapeutics Inc. TRVI | 1,786,867 | $33.3 million | 0.68% | no change |
| Oric Pharmaceuticals Inc. ORIC | 2,998,192 | $32.5 million | 0.66% | no change |
| Alphabet Inc. GOOGL | 90,000 | $32.2 million | 0.65% | +24,297 |
| DBV Technologies S A DBVT | 1,857,362 | $30.5 million | 0.62% | no change |
| Absci Corporation ABSI | 2,474,764 | $28.7 million | 0.58% | +674,764 |
| Sionna Therapeutics Inc SION | 610,515 | $26.9 million | 0.55% | +310,515 |
| Rapport Therapeutics Inc. RAPP | 641,469 | $26.7 million | 0.54% | no change |
| Amylyx Pharmaceuticals Inc. AMLX | 1,480,586 | $26.6 million | 0.54% | +250,586 |
| Annexon Inc. ANNX | 4,458,646 | $25.5 million | 0.52% | +500,000 |
| Monopar Therapeutics Inc. MNPR | 270,118 | $25.0 million | 0.51% | no change |
| Oruka Therapeutics Inc. ORKA | 250,000 | $23.8 million | 0.48% | new |
| Seaport Therapeutics Inc. SPTX | 1,095,316 | $23.8 million | 0.48% | new |
| Galecto Inc. DMRA | 900,000 | $23.4 million | 0.48% | no change |
| Tyra Biosciences Inc. TYRA | 725,000 | $23.2 million | 0.47% | new |
| Zura Bio Ltd ZURA | 3,734,866 | $22.0 million | 0.45% | no change |
| Taiwan Semiconductor Manufacturing Company Limited TSM | 44,700 | $21.3 million | 0.43% | +2,500 |
| NVIDIA Corp. NVDA | 95,000 | $19.0 million | 0.39% | +5,915 |
| Rezolute Inc. RZLT | 3,328,287 | $17.3 million | 0.35% | no change |
| Maplight Therapeutics Inc. MPLT | 450,000 | $16.1 million | 0.33% | no change |
| Neumora Therapeutics Inc. NMRA | 8,497,822 | $14.4 million | 0.29% | no change |
| Yandex N V NBIS | 52,000 | $14.4 million | 0.29% | -61,614 |
| Microsoft Corp. MSFT | 37,500 | $14.0 million | 0.28% | -3,880 |
| Cytomx Therapeutics Inc. CTMX | 3,457,711 | $13.0 million | 0.26% | no change |
| Generate Biomedicines Inc. GENB | 736,104 | $12.4 million | 0.25% | no change |
| Inhibikase Therapeutics Inc. IKT | 5,850,000 | $11.9 million | 0.24% | no change |
| Adagene Inc. ADAG | 2,666,666 | $11.2 million | 0.23% | new |
| Engene Therapeut ENGN | 6,256,662 | $10.8 million | 0.22% | new |
| Aadi Bioscience Inc. WHWK | 2,337,102 | $10.7 million | 0.22% | +255,102 |
| Datadog, Inc. DDOG | 40,000 | $10.4 million | 0.21% | -14,300 |
| ServiceNow, Inc. NOW | 100,000 | $9.9 million | 0.20% | +12,910 |
| Broadcom Inc. AVGO | 25,000 | $9.4 million | 0.19% | +10,000 |
| Ionq Inc. Com IONQ | 170,000 | $9.1 million | 0.18% | no change |
| Jfrog Ltd FROG | 95,500 | $8.7 million | 0.18% | -33,316 |
| Oculis Holding AG OCS | 625,000 | $8.7 million | 0.18% | new |
| Iris Energy Ltd IREN | 175,000 | $8.0 million | 0.16% | +131,900 |
| Amazon.com Inc. AMZN | 32,500 | $7.7 million | 0.16% | -14,141 |
| CrowdStrike Holdings, Inc. CRWD | 10,000 | $7.6 million | 0.15% | -13,070 |
| Design Therapeutics Inc. DSGN | 523,212 | $7.6 million | 0.15% | new |
| PDD Holdings Inc. PDD | 95,000 | $7.2 million | 0.15% | +11,599 |
| Satellos Bioscience Inc. MSLE | 892,074 | $6.9 million | 0.14% | no change |
| Dynatrace, Inc. DT | 155,000 | $6.8 million | 0.14% | +5,000 |
| Tenax Therapeutics Inc. TENX | 427,141 | $6.2 million | 0.13% | no change |
| VTV Therapeutics Inc. Class A New VTVT | 163,000 | $6.1 million | 0.12% | no change |
| Eloxx Pharmaceuticals Inc. ELOX | 400,000 | $5.6 million | 0.11% | new |
| Agomab Therapeutics NV AGMB | 411,250 | $5.3 million | 0.11% | no change |
| Alibaba Group Holding Limited BABA | 50,000 | $4.8 million | 0.10% | new |
| Korro Bio Inc. KRRO | 347,718 | $4.6 million | 0.09% | no change |
| Cellebrite Di Ltd CLBT | 311,544 | $4.5 million | 0.09% | no change |
| Invivyd Inc. IVVD | 5,000,000 | $4.4 million | 0.09% | +1,000,000 |
| Ouster Inc. OUST | 67,500 | $4.2 million | 0.09% | new |
| Palisade Bio Inc. PALI | 2,000,000 | $4.2 million | 0.08% | new |
| Aeva Technologies Inc. AEVA | 145,459 | $4.2 million | 0.08% | +35,459 |
| Seer Inc. SEER | 2,458,673 | $4.1 million | 0.08% | no change |
| I Mab NBP | 2,004,739 | $3.9 million | 0.08% | -995,261 |
| Gitlab Inc. GTLB | 125,000 | $3.8 million | 0.08% | +25,000 |
| Odyssey Therapeutics, Inc. ODTX | 200,000 | $3.7 million | 0.08% | new |
| Foghorn Therapeutics Inc. FHTX | 720,720 | $3.5 million | 0.07% | no change |
| Agenus Inc. AGEN | 1,064,250 | $3.3 million | 0.07% | no change |
| monday.com Ltd. MNDY | 42,500 | $3.1 million | 0.06% | +17,500 |
| Zoetis Inc. ZTS | 35,000 | $2.5 million | 0.05% | new |
| Workiva Inc. WK | 45,000 | $2.2 million | 0.04% | -47,500 |
| Netflix Inc. NFLX | 25,000 | $1.8 million | 0.04% | new |
| Kalaris Therapeutics Inc KLRS | 435,798 | $1.8 million | 0.04% | no change |
| Quantinuum Inc. QNT | 20,000 | $1.6 million | 0.03% | new |
| Rani Therapeutics Holdings-A RANI | 2,000,000 | $1.5 million | 0.03% | no change |
| Tesla, Inc. TSLA | 3,500 | $1.5 million | 0.03% | -18,000 |
| KE Holdings Inc. BEKE | 100,000 | $1.5 million | 0.03% | no change |
| Entera Bio Ltd ENTX | 736,457 | $1.3 million | 0.03% | new |
| Medline Inc. MDLN | 25,000 | $986,000 | 0.02% | no change |
| Lumentum Holdings Inc. LITE | 1,055 | $905,253 | 0.02% | new |
| Figma Inc. FIG | 50,000 | $904,500 | 0.02% | no change |
| Gossamer Bio Inc. GOSS | 5,208,968 | $857,396 | 0.02% | no change |
| Fox Corp. FOXA | 10,000 | $521,600 | 0.01% | new |
| AT&T Inc. T | 25,000 | $517,500 | 0.01% | new |
| Nu Holdings Ltd. NU | 25,000 | $334,000 | 0.01% | no change |
Every US-listed position in the fund's 13F for the quarter ended 30 June 2026, by the value it reported.
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Change is shares against its 13F for the quarter before; the 10 it sold out of are in the box above.Options it reported
| Company | Option | Shares under the options | Value of those shares |
|---|---|---|---|
| Microsoft Corp. MSFT | Calls | 24,000 | $9.0 million |
| Apple Inc. AAPL | Calls | 23,000 | $6.7 million |
2 option lines. A 13F lists calls and puts by the shares they cover and what those shares were worth at the quarter's end, not what the options cost; they are not counted in the holdings above.