Institutional Manager · CIK 0002005245
Siren, L.L.C.
New York, NY · File #028-24464
Latest AUM
$3.35B
Positions
115
Top-10 Concentration
51.2%
Filings
7
Portfolio Value Over Time
2024-09
2024-12
2025-03
2025-06
2025-09
2025-12
Biggest QoQ Changes
Ranked by conviction flow (share change × current price) so mark-to-market moves don't dominate. Price effect column shows how much of the $ change was just the stock moving.
| Action | Issuer | Ticker / CUSIP | Δ Shares | Flow ($) | Price Effect |
|---|---|---|---|---|---|
| NEW | Olema Pharmaceuticals Inc | OLMA | +3,300,700 | +$82.5M | $0 |
| REDUCE | Arrowhead Pharmaceuticals Inc | ARWR | -1,169,404 | -$77.6M | +$85.2M |
| ADD | Scholar Rock Holding Corp | SRRK | +1,575,008 | +$69.4M | +$63.0M |
| EXITED | Avidity Biosciences Inc | 05370A108 | -1,285,610 | -$56.0M | $0 |
| EXITED | Rezolute Inc | 76200L309 | -4,870,000 | -$45.8M | $0 |
| NEW | Zymeworks Inc | ZYME | +1,680,121 | +$44.2M | $0 |
| NEW | Dbv Technologies SA | DBVTF | +1,857,362 | +$35.6M | $0 |
| EXITED | Soleno Therapeutics Inc | 834203309 | -467,342 | -$31.6M | $0 |
| NEW | enGene Holdings Inc | ENGNW | +3,336,264 | +$30.1M | $0 |
| ADD | RAPT Therapeutics Inc | 75382E208 | +794,534 | +$26.9M | +$4.7M |
Sector Allocation
Filing History
- 13F HOLDINGS REPORTQ/E Dec 2025115 pos · $3.35B
- 13F HOLDINGS REPORTQ/E Sep 2025117 pos · $2.56B
- 13F HOLDINGS REPORTQ/E Jun 2025111 pos · $1.93B
- 13F HOLDINGS REPORT (Amended)Q/E Mar 2025117 pos · $1.77B
- 13F HOLDINGS REPORTQ/E Mar 2025117 pos · $1.76B
- 13F HOLDINGS REPORTQ/E Dec 2024119 pos · $2.26B
- 13F HOLDINGS REPORTQ/E Sep 2024112 pos · $2.00B
Top 20 Holdings — Dec 2025
| # | Issuer | Ticker | Shares | Value | % of Portfolio |
|---|---|---|---|---|---|
| 1 | Scholar Rock Holding Corp | SRRK | 10,825,013 | $476.8M | 15.72% |
| 2 | Kymera Therapeutics Inc | KYMR | 3,286,830 | $255.7M | 8.43% |
| 3 | BeOne Medicines AG | BEIGF | 500,000 | $151.9M | 5.01% |
| 4 | Edgewise Therapeutics Inc | EWTX | 4,529,990 | $112.4M | 3.71% |
| 5 | Revolution Medicines Inc | RVMDW | 1,335,075 | $106.3M | 3.51% |
| 6 | Centessa Pharmaceuticals PLC | CNTA | 4,027,517 | $100.7M | 3.32% |
| 7 | Arrowhead Pharmaceuticals Inc | ARWR | 1,500,476 | $99.6M | 3.28% |
| 8 | Bicara Therapeutics Inc | BCAX | 5,216,969 | $87.8M | 2.89% |
| 9 | Olema Pharmaceuticals Inc | OLMA | 3,300,700 | $82.5M | 2.72% |
| 10 | Disc Medicine Inc | IRON | 988,401 | $78.5M | 2.59% |
| 11 | Structure Therapeutics Inc | GPCR | 1,078,698 | $75.0M | 2.47% |
| 12 | Tango Therapeutics Inc | TNGX | 8,165,374 | $72.3M | 2.38% |
| 13 | Stoke Therapeutics Inc | STOK | 2,247,347 | $71.3M | 2.35% |
| 14 | Crinetics Pharmaceuticals Inc | CRNX | 1,507,636 | $70.2M | 2.31% |
| 15 | Dyne Therapeutics Inc | DYN | 3,502,941 | $68.5M | 2.26% |
| 16 | Apellis Pharmaceuticals Inc | APLS | 2,578,396 | $64.8M | 2.14% |
| 17 | Cogent Biosciences Inc | COGT | 1,629,279 | $57.9M | 1.91% |
| 18 | Septerna Inc | SEPN | 2,000,000 | $55.8M | 1.84% |
| 19 | Taysha Gene Therapies Inc | TSHA | 10,129,913 | $55.7M | 1.84% |
| 20 | Rhythm Pharmaceuticals Inc | RYTM | 499,975 | $53.5M | 1.76% |