Siren, L.L.C.

In its 13F for Q2 2025 (holdings as of June 30, 2025, filed August 13, 2025), Siren, L.L.C. reported 110 stock positions worth $1.9 billion. Its top holding was Scholar Rock (SRRK) at 17.0% of the portfolio, followed by Kymera Therapeutics (KYMR, 7.7%) and Beone Medicines Ltd.-ADR (ONC, 6.4%). Compared with Q1 2025, it opened 15 new positions, sold out of 21, added to 21 and reduced 19. The biggest buy was Kymera Therapeutics (KYMR, shares +6%) and the biggest sale an exit from Blueprint Medicines (BPMC).

Most Recent 13F
Q2 2026
Location
New York, NY
CIK
0002005245
Portfolio Value
$1.9B (Q2 2025)
SEC Filing
0002005369-25-000014 ↗ filed Aug 13, 2025

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 $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 Q2 2026

Holdings 110 stocks · $1.9B
SRRK Scholar Rock Holding Corp. 16.95% 9,250,005 $327.6M No change
KYMR Kymera Therapeutics Inc. 7.74% 3,428,150 $149.6M Add +5.8%
ONC Beone Medicines Ltd.-ADR 6.39% 509,990 $123.5M Add +2.3%
IRON Disc Medicine Inc. 3.01% 1,099,401 $58.2M Add +2.6%
CRNX Crinetics Pharmaceuticals Inc. 2.51% 1,688,611 $48.6M No change
BCAX Bicara Therapeutics Inc. 2.51% 5,216,969 $48.5M Add +59.7%
DYN Dyne Therapeutics Inc. 2.38% 4,836,437 $46.0M Add +77.9%
CNTA Centessa Pharmaceuticals Ltd. 2.35% 3,460,029 $45.5M Add +16.9%
MRUS Merus NV 2.32% 853,467 $44.9M Reduce -18.2%
APLS Apellis Pharmaceuticals Inc. 2.31% 2,578,396 $44.6M No change
ASND Ascendis Pharma A/S 2.20% 245,943 $42.4M Reduce -14.4%
ARWR Arrowhead Pharmaceuticals Inc. 2.18% 2,669,880 $42.2M No change
EWTX Edgewise Therapeutics Inc. 2.14% 3,160,298 $41.4M Add +86.3%
SLNO Soleno Therapeutics Inc. 2.03% 467,342 $39.2M Reduce -35.8%
LXRX Lexicon Pharmaceuticals Inc. 1.90% 38,918,903 $36.8M No change
TBLA Taboola.com Ltd. 1.89% 9,969,495 $36.5M No change
SLDB Solid Biosciences Inc. 1.87% 7,415,905 $36.1M No change
RVMD Revolution Medicines Inc. 1.79% 938,755 $34.5M Add +66.5%
RNAM Avidity Biosciences Inc. 1.63% 1,110,610 $31.5M No change
RYTM Rhythm Pharmaceuticals Inc. 1.34% 409,742 $25.9M Add +47.6%
APGE Apogee Therapeutics Inc. 1.34% 594,994 $25.8M No change
STOK Stoke Therapeutics Inc. 1.32% 2,247,347 $25.5M No change
TSHA Taysha Gene Therapies Inc. 1.32% 11,014,737 $25.4M Add +69.1%
XENE Xenon Pharmaceuticals Inc. 1.32% 812,761 $25.4M Add +10.9%
WVE Wave Life Sciences Ltd. 1.24% 3,696,322 $24.0M No change
MLTX Moonlake Immunotherapeutics 1.24% 508,267 $24.0M New
SEPN Septerna Inc. 1.20% 2,202,514 $23.3M No change
NAMS Newamsterdam Pharma Co. NV 1.12% 1,194,240 $21.6M Reduce -37.5%
TRVI Trevi Therapeutics Inc. 1.11% 3,938,793 $21.5M Add +37.5%
TNGX Tango Therapeutics Inc. 0.89% 3,364,814 $17.2M Add +31.2%
AKRO Akero Therapeutics Inc. 0.88% 318,647 $17.0M New
SLN Silence Therapeutics PLC-ADR 0.87% 2,911,438 $16.9M Add +4.4%
AVBP Arrivent Biopharma Inc. 0.79% 700,000 $15.2M New
BCYC Bicycle Therapeutics PLC-ADR 0.72% 2,012,752 $14.0M Add +11.0%
RCUS Arcus Biosciences Inc. 0.68% 1,612,077 $13.1M No change
IHS Ihs Holding Ltd. 0.68% 2,357,520 $13.1M No change
AMZN Amazon.com Inc. 0.64% 56,500 $12.4M No change
DNLI Denali Therapeutics Inc. 0.59% 821,513 $11.5M No change
ERAS Erasca Inc. 0.58% 8,757,249 $11.1M No change
ORIC Oric Pharmaceuticals Inc. 0.53% 1,007,575 $10.2M No change
RELY Remitly Global Inc. 0.50% 515,449 $9.7M Add +5.1%
PCVX Vaxcyte Inc. 0.50% 295,543 $9.6M No change
CRWD CrowdStrike Holdings Inc. Class A 0.49% 18,500 $9.4M Reduce -26.0%
CGEM Cullinan Therapeutics Inc. 0.47% 1,193,410 $9.0M No change
GOOGL Alphabet Inc. Class A 0.46% 50,703 $8.9M No change
UPB Upstream Bio Inc. 0.45% 788,450 $8.7M No change
SEER Seer Inc. 0.44% 4,000,000 $8.6M No change
MSFT Microsoft Corp. 0.42% 16,150 $8.0M Reduce -43.3%
NVDA Nvidia Corp. 0.41% 49,985 $7.9M Add +12.5%
IONQ Ionq Inc. 0.38% 170,000 $7.3M No change
TSM Taiwan Semiconductor-SP ADR 0.36% 30,500 $6.9M Add +7.0%
GOSS Gossamer Bio Inc. 0.33% 5,208,968 $6.4M No change
CRM Salesforce Inc. 0.32% 22,600 $6.2M Add +54.8%
COGT Cogent Biosciences Inc. 0.32% 854,379 $6.1M New
RNAC Cartesian Therapeutics Inc. 0.30% 563,272 $5.9M No change
VERA Vera Therapeutics Inc. 0.30% 247,216 $5.8M Reduce -66.9%
ADBE Adobe Inc. 0.30% 15,051 $5.8M Reduce -22.0%
SION Sionna Therapeutics Inc. 0.29% 325,000 $5.6M No change
PDD PDD Holdings Inc. 0.29% 52,901 $5.5M No change
SGMT Sagimet Biosciences Inc. Class A 0.29% 724,771 $5.5M No change
SYRE Spyre Therapeutics Inc. 0.29% 368,598 $5.5M No change
PCRX Pacira Biosciences Inc. 0.28% 225,000 $5.4M New
NOW ServiceNow Inc. 0.27% 5,126 $5.3M Reduce -43.8%
KRRO Korro Bio Inc. 0.27% 418,833 $5.2M No change
DDOG Datadog Inc. Class A 0.27% 38,425 $5.2M Reduce -19.0%
AGEN Agenus Inc. 0.25% 1,064,250 $4.9M Add +112.8%
FROG Jfrog Ltd. 0.24% 107,116 $4.7M Reduce -18.6%
RAPP Rapport Therapeutics Inc. 0.22% 378,469 $4.3M No change
TIL Instil Bio Inc. 0.22% 203,933 $4.2M No change
DT Dynatrace Inc. 0.21% 75,229 $4.2M Reduce -14.3%
WHWK Whitehawk Therapeutics Inc. 0.20% 2,082,000 $3.9M No change
EDU New Oriental Educatio-SP ADR 0.20% 72,000 $3.9M Reduce -9.4%
IGMS Igm Biosciences Inc. 0.19% 3,255,826 $3.6M No change
FHTX Foghorn Therapeutics Inc. 0.18% 720,720 $3.4M No change
VIGL Vigil Neuroscience Inc. 0.17% 411,191 $3.3M Reduce -79.1%
NMRA Neumora Therapeutics Inc. 0.17% 4,358,283 $3.2M No change
PRQR Proqr Therapeutics NV 0.16% 1,552,183 $3.2M No change
NBIS Nebius Group NV 0.15% 51,000 $2.8M Reduce -63.6%
BDTX Black Diamond Therapeutics I 0.13% 1,046,517 $2.6M No change
LXEO Lexeo Therapeutics Inc. 0.13% 603,435 $2.4M No change
PANW Palo Alto Networks Inc. 0.12% 11,500 $2.4M No change
QCOM Qualcomm Inc. 0.12% 14,000 $2.2M No change
WK Workiva Inc. 0.10% 28,000 $1.9M Add +60.0%
ELDN Eledon Pharmaceuticals Inc. 0.10% 690,170 $1.9M No change
BEKE Ke Holdings Inc.-ADR filed as KE HLDGS INC 0.10% 105,000 $1.9M No change
HUBS HubSpot Inc. 0.09% 3,000 $1.7M New
UNH Unitedhealth Group Inc. 0.08% 5,076 $1.6M New
BIOA Bioage Labs Inc. 0.08% 382,406 $1.6M No change
GTLB Gitlab Inc. Class A 0.08% 35,000 $1.6M New
TRML Tourmaline Bio Inc. 0.08% 91,426 $1.5M No change
RCKT Rocket Pharmaceuticals Inc. 0.07% 591,263 $1.4M No change
TSLA Tesla Inc. 0.07% 4,000 $1.3M Reduce -55.6%
BIRK Birkenstock Holding PLC 0.06% 25,000 $1.2M New
SAIL Sailpoint Inc. 0.06% 50,000 $1.1M Reduce -47.4%
SEMR Semrush Holdings Inc. Class A 0.06% 125,000 $1.1M No change
PRMB Primo Brands Corp. 0.06% 37,500 $1.1M New
CLBT Cellebrite Di Ltd. 0.05% 60,000 $960K New
GBIO Generation Bio Co. 0.05% 2,968,925 $950K No change
KLRS Kalaris Therapeutics Inc. 0.04% 282,586 $755K No change
HOOK Hookipa Pharma Inc. 0.04% 566,640 $711K No change
TEAM Atlassian Corp. Class A 0.04% 3,500 $711K New
PCOR Procore Technologies Inc. 0.04% 10,000 $684K No change
CCC CCC Intelligent Solutions Ho 0.02% 50,000 $471K New
PCG P G & E Corp. 0.02% 25,000 $349K New
CYCLERION THERAPEUTICS INC 0.02% 116,155 $338K No change
RDDT Reddit Inc. Class A 0.02% 2,000 $301K Reduce -91.5%
VRT Vertiv Holdings Co. Class A 0.01% 2,000 $257K New
DECK Deckers Outdoor Corp. 0.01% 2,000 $206K Reduce -60.0%
CRBU Caribou Biosciences Inc. 0.01% 105,347 $133K No change
IRWD Ironwood Pharmaceuticals Inc. 0.00% 110,532 $80K No change

Portfolio Sells Q1 2025 → Q2 2025
BPMC Blueprint Medicines Corp. Sold out 0.00% −3.63
NAMS Newamsterdam Pharma Co. NV Reduce -37.5% 1.12% −1.09
SLNO Soleno Therapeutics Inc. Reduce -35.8% 2.03% −0.91
PRTA Prothena Corp. PLC Sold out 0.00% −0.90
SMMT Summit Therapeutics Inc. Sold out 0.00% −0.76
VERA Vera Therapeutics Inc. Reduce -66.9% 0.30% −0.71
ASND Ascendis Pharma A/S Reduce -14.4% 2.20% −0.33
MTSR Metsera Inc. Sold out 0.00% −0.23
MSFT Microsoft Corp. Reduce -43.3% 0.42% −0.19
MRUS Merus NV Reduce -18.2% 2.32% −0.15
LPLA LPL Financial Holdings Inc. Sold out 0.00% −0.14
NOW ServiceNow Inc. Reduce -43.8% 0.27% −0.14
MRVL Marvell Technology Inc. Sold out 0.00% −0.13
RDDT Reddit Inc. Class A Reduce -91.5% 0.02% −0.12
ADBE Adobe Inc. Reduce -22.0% 0.30% −0.12
SARO Standardaero Inc. Sold out 0.00% −0.09
BILL Bill Holdings Inc. Sold out 0.00% −0.07
PYPL PayPal Holdings Inc. Sold out 0.00% −0.07
TSLA Tesla Inc. Reduce -55.6% 0.07% −0.07
PEGA Pegasystems Inc. Sold out 0.00% −0.06
MDB Mongodb Inc. Sold out 0.00% −0.05
NKE Nike Inc. Class B Sold out 0.00% −0.05
INTC Intel Corp. Sold out 0.00% −0.05
INFA Informatica Inc. Class A Sold out 0.00% −0.05
BA The Boeing Co. Sold out 0.00% −0.05
BASE Couchbase Inc. Sold out 0.00% −0.04
SAIL Sailpoint Inc. Reduce -47.4% 0.06% −0.04
KRON Kronos Bio Inc. Sold out 0.00% −0.04
RACE Ferrari NV Sold out 0.00% −0.04
USB US Bancorp Sold out 0.00% −0.03
VIGL Vigil Neuroscience Inc. Reduce -79.1% 0.17% −0.03
OXY Occidental Petroleum Corp. Sold out 0.00% −0.03
DECK Deckers Outdoor Corp. Reduce -60.0% 0.01% −0.02
NBIS Nebius Group NV Reduce -63.6% 0.15% −0.02
DT Dynatrace Inc. Reduce -14.3% 0.21% −0.02
GDS GDS Holdings Ltd. - ADR Sold out 0.00% −0.02
EDU New Oriental Educatio-SP ADR Reduce -9.4% 0.20% −0.01
CRWD CrowdStrike Holdings Inc. Class A Reduce -26.0% 0.49% −0.01
DDOG Datadog Inc. Class A Reduce -19.0% 0.27% +0.00
FROG Jfrog Ltd. Reduce -18.6% 0.24% +0.01

Portfolio Buys Q1 2025 → Q2 2025
KYMR Kymera Therapeutics Inc. Add +5.8% 7.74% +2.74
MLTX Moonlake Immunotherapeutics New 1.24% +1.24
AKRO Akero Therapeutics Inc. New 0.88% +0.88
TSHA Taysha Gene Therapies Inc. Add +69.1% 1.32% +0.81
AVBP Arrivent Biopharma Inc. New 0.79% +0.79
DYN Dyne Therapeutics Inc. Add +77.9% 2.38% +0.78
TNGX Tango Therapeutics Inc. Add +31.2% 0.89% +0.69
RVMD Revolution Medicines Inc. Add +66.5% 1.79% +0.66
RYTM Rhythm Pharmaceuticals Inc. Add +47.6% 1.34% +0.51
SLN Silence Therapeutics PLC-ADR Add +4.4% 0.87% +0.43
COGT Cogent Biosciences Inc. New 0.32% +0.32
PCRX Pacira Biosciences Inc. New 0.28% +0.28
AGEN Agenus Inc. Add +112.8% 0.25% +0.21
NVDA Nvidia Corp. Add +12.5% 0.41% +0.14
BCAX Bicara Therapeutics Inc. Add +59.7% 2.51% +0.11
TRVI Trevi Therapeutics Inc. Add +37.5% 1.11% +0.10
CRM Salesforce Inc. Add +54.8% 0.32% +0.10
TSM Taiwan Semiconductor-SP ADR Add +7.0% 0.36% +0.09
HUBS HubSpot Inc. New 0.09% +0.09
UNH Unitedhealth Group Inc. New 0.08% +0.08
GTLB Gitlab Inc. Class A New 0.08% +0.08
BIRK Birkenstock Holding PLC New 0.06% +0.06
PRMB Primo Brands Corp. New 0.06% +0.06
CLBT Cellebrite Di Ltd. New 0.05% +0.05
EWTX Edgewise Therapeutics Inc. Add +86.3% 2.14% +0.04
TEAM Atlassian Corp. Class A New 0.04% +0.04
CCC CCC Intelligent Solutions Ho New 0.02% +0.02
WK Workiva Inc. Add +60.0% 0.10% +0.02
PCG P G & E Corp. New 0.02% +0.02
VRT Vertiv Holdings Co. Class A New 0.01% +0.01
IRON Disc Medicine Inc. Add +2.6% 3.01% +0.01
CNTA Centessa Pharmaceuticals Ltd. Add +16.9% 2.35% −0.05
XENE Xenon Pharmaceuticals Inc. Add +10.9% 1.32% −0.07
RELY Remitly Global Inc. Add +5.1% 0.50% −0.07
BCYC Bicycle Therapeutics PLC-ADR Add +11.0% 0.72% −0.14
ONC Beone Medicines Ltd.-ADR Add +2.3% 6.39% −1.27

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