Siren, L.L.C. holds a focused book of 100 stocks worth $3.6B as of Q1 2026 (disclosed May 14, 2026, a ~45-day 13F lag). This quarter they opened Veradermics Inc and trimmed Kymera Therapeutics Inc. Their largest long position is Scholar Rock Holding Corp at 15% of the equity book.
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Use Arkolith to show Siren, L.L.C.'s latest holdings, largest changes, and filing provenance.
Top-heavy: focused book
Share of the disclosed book in its largest positions. A higher top-5 share means a more concentrated, higher-conviction portfolio.
99% mapped to company sectors
Direct operating-company sectors from our SIC-based security master. ETF/fund and unclassified holdings stay visible separately; this is not ETF look-through exposure.
Estimated $ traded · quarter-end prices, no cost basis
Bars show each stock's share of the portfolio. Click a row for its position history.
| # | Security | Value | Shares | % Port | Last move | History |
|---|---|---|---|---|---|---|
| 1 | Scholar Rock Holding Corp COM | $532.2M | 10.83M | 14.8% | —Held | |
| 2 | Kymera Therapeutics Inc COM | $265.4M | 3.19M | 7.4% | ▼−3.0% Reduced · −100K sh | |
| 3 | Erasca Inc COM | $181.9M | 11.24M | 5.0% | ▲+28% Added · +2.5M sh | |
| 4 | Edgewise Therapeutics Inc COM | $139.6M | 4.43M | 3.9% | ▼−2.2% Reduced · −100K sh | |
| 5 | BeOne Medicines AG SPONSORED ADS | $138.1M | 465.0K | 3.8% | ▼−7.0% Reduced · −35K sh | |
| 6 | Tango Therapeutics Inc COM | $118.3M | 5.66M | 3.3% | ▼−31% Reduced · −2.5M sh | |
| 7 | Bicara Therapeutics Inc COM | $115.4M | 5.80M | 3.2% | ▲+11% Added · +586K sh | |
| 8 | Revolution Medicines Inc COM | $108.0M | 1.11M | 3.0% | ▼−17% Reduced · −224K sh | |
| 9 | Arrowhead Pharmaceuticals Inc COM | $101.3M | 1.62M | 2.8% | ▲+7.7% Added · +115K sh | |
| 10 | Veradermics Inc COMMON STOCK | $95.1M | 1.51M | 2.6% | ▲New New position | |
| 11 | Xenon Pharmaceuticals Inc COM | $76.7M | 1.32M | 2.1% | ▲+62% Added · +506K sh | |
| 12 | Olema Pharmaceuticals Inc COM | $70.9M | 4.76M | 2.0% | ▲+44% Added · +1.5M sh | |
| 13 | Crinetics Pharmaceuticals Inc COM | $69.1M | 1.90M | 1.9% | ▲+26% Added · +396K sh | |
| 14 | Lexicon Pharmaceuticals Inc COM NEW | $69.1M | 44.30M | 1.9% | ▲+14% Added · +5.4M sh | |
| 15 | Cogent Biosciences Inc COM | $65.8M | 1.71M | 1.8% | ▲+4.9% Added · +80K sh | |
| 16 | Stoke Therapeutics Inc COM | $65.0M | 2.00M | 1.8% | ▼−11% Reduced · −252K sh | |
| 17 | Arcus Biosciences Inc COM | $65.0M | 3.01M | 1.8% | —Held | |
| 18 | Structure Therapeutics Inc SPONSORED ADS | $64.0M | 1.33M | 1.8% | ▲+23% Added · +250K sh | |
| 19 | Disc Medicine Inc COM | $63.2M | 988.4K | 1.8% | —Held | |
| 20 | Rhythm Pharmaceuticals Inc COM | $63.1M | 725.5K | 1.7% | ▲+45% Added · +226K sh | |
| 21 | Solid Biosciences Inc COM NEW | $55.4M | 7.69M | 1.5% | —Held | |
| 22 | Septerna Inc COM | $48.1M | 2.00M | 1.3% | —Held | |
| 23 | Centessa Pharmaceuticals PLC SPONSORED ADS | $41.8M | 1.05M | 1.2% | ▼−74% Reduced · −3.0M sh | |
| 24 | Spyre Therapeutics Inc COM NEW | $41.3M | 818.6K | 1.1% | —Held | |
| 25 | Cytokinetics Inc COM NEW | $40.5M | 614.0K | 1.1% | ▲New New position | |
| 26 | Dyne Therapeutics, Inc COM | $40.4M | 2.23M | 1.1% | ▼−36% Reduced · −1.3M sh | |
| 27 | Taysha Gene Therapies Inc COM SHS | $39.5M | 8.83M | 1.1% | ▼−13% Reduced · −1.3M sh | |
| 28 | Dbv Technologies SA SPONSORED ADS | $38.8M | 1.86M | 1.1% | —Held | |
| 29 | Oric Pharmaceuticals Inc COM | $38.0M | 3.00M | 1.1% | ▲+198% Added · +2.0M sh | |
| 30 | enGene Holdings Inc COM | $35.8M | 5.25M | 1.0% | ▲+57% Added · +1.9M sh | |
| 31 | Palvella Therapeutics Inc COM | $32.1M | 257.5K | 0.9% | ▲+243% Added · +182K sh | |
| 32 | Taboola.com Ltd ORD SHS | $30.9M | 9.97M | 0.9% | —Held | |
| 33 | Enliven Therapeutics Inc COM | $29.3M | 746.2K | 0.8% | ▲New New position | |
| 34 | Denali Therapeutics Inc COM | $26.8M | 1.40M | 0.7% | —Held | |
| 35 | Remitly Global Inc COM | $24.2M | 1.54M | 0.7% | ▼−4.6% Reduced · −75K sh | |
| 36 | Damora Therapeutics Inc COM NEW | $23.3M | 900.0K | 0.6% | ▲New New position | |
| 37 | Zura Bio Ltd CLASS A ORD SHS | $22.2M | 3.73M | 0.6% | ▲+187% Added · +2.4M sh | |
| 38 | Annexon Inc COM | $21.9M | 3.96M | 0.6% | ▲New New position | |
| 39 | Trevi Therapeutics Inc COM | $21.3M | 1.79M | 0.6% | ▼−22% Reduced · −500K sh | |
| 40 | Rapport Therapeutics Inc COM | $20.1M | 641.5K | 0.6% | ▼−9.4% Reduced · −67K sh | |
| 41 | Alphabet Inc CAP STK CL A | $18.9M | 65.7K | 0.5% | ▲+217% Added · +45K sh | |
| 42 | Fulcrum Therapeutics Inc COM | $18.0M | 2.35M | 0.5% | ▲+21% Added · +400K sh | |
| 43 | WAVE Life Sciences Ltd SHS | $17.8M | 2.45M | 0.5% | —Held | |
| 44 | Definium Therapeutics Inc COM SHS | $17.4M | 919.5K | 0.5% | ▲New New position | |
| 45 | Amylyx Pharmaceuticals Inc COM | $17.1M | 1.23M | 0.5% | ▲New New position | |
| 46 | Cullinan Therapeutics Inc COM | $17.0M | 1.19M | 0.5% | —Held | |
| 47 | Neumora Therapeutics Inc COM | $16.6M | 8.50M | 0.5% | ▲+35% Added · +2.2M sh | |
| 48 | Uniqure NV SHS | $16.4M | 1.00M | 0.5% | ▲New New position | |
| 49 | CytomX Therapeutics Inc COM | $16.3M | 3.46M | 0.5% | ▲New New position | |
| 50 | Nvidia Corp COM | $15.5M | 89.1K | 0.4% | ▲+138% Added · +52K sh |
As-of date vs the date the SEC received each filing
| Quarter | As of | Filed | Positions | Value | Form |
|---|---|---|---|---|---|
| Q1 2026 | Mar 31, 2026 | May 14, 2026 | 102 | $3.6B | 13F-HR |
| Q4 2025 | Dec 31, 2025 | Feb 13, 2026 | 115 | $3.4B | 13F-HR |
| Q3 2025 | Sep 30, 2025 | Nov 13, 2025 | 117 | $2.6B | 13F-HR |
| Q2 2025 | Jun 30, 2025 | Aug 13, 2025 | 111 | $1.9B | 13F-HR |
| Q1 2025 | Mar 31, 2025 | May 23, 2025 | 117 | $1.8B | 13F-HR/A |
| Q4 2024 | Dec 31, 2024 | Feb 14, 2025 | 119 | $2.3B | 13F-HR |
| Q3 2024 | Sep 30, 2024 | Nov 13, 2024 | 112 | $2.0B | 13F-HR |
Holdings from SEC EDGAR 13F-HR filings, updated quarterly ~45 days after quarter-end. Public domain. The book and weighting are long equity only; disclosed put/call options are listed separately and excluded from those totals. Price-derived performance is withheld until the price-source policy and freshness gate are green.