Siren, L.L.C. reported 111 positions worth $4.86B for the quarter ended Jun 30, 2026, up 39.2% on the prior quarter. It opened 22 new positions, added to 32, trimmed 20 and exited 8. Its largest holding is Scholar Rock Holding Corp at 10.8% of the portfolio.
Reported 13F market value at each quarter end. A change mixes trading with price moves in the positions held.
Dollar value of shares bought and sold each quarter, at that quarter’s price. It counts trading only, not price changes.
How many positions were opened, added to, trimmed or closed each quarter.
Share of reported value in each sector at every quarter end.
| Holding | Change | Change % | Trade Value | Weight |
|---|---|---|---|---|
| PBLS Parabilis Medicines, Inc. | +2.99M | – | $81.90M | 1.69% |
| ABVX Abivax S.A. | +576.0K | – | $76.76M | 1.58% |
| COAG Hemab Therapeutics Holdings, Inc. | +2.09M | – | $76.65M | 1.58% |
| RLAY Relay Therapeutics, Inc. | +3.65M | – | $68.29M | 1.41% |
| ELVN Enliven Therapeutics, Inc. | +1.03M | +137.8% | $52.18M | 1.85% |
| KLRA Kailera Therapeutics, Inc. | +2.21M | – | $48.78M | 1% |
| RYTM Rhythm Pharmaceuticals, Inc. | +410.8K | +56.6% | $45.61M | 2.6% |
| COF Capital One Financial Corp | +171.6K | – | $34.43M | 0.709% |
| ORKA Oruka Therapeutics, Inc. | +250.0K | – | $23.79M | 0.49% |
| SPTX Seaport Therapeutics, Inc. | +1.10M | – | $23.79M | 0.49% |
| Holding | Change | Change % | Trade Value | Weight |
|---|---|---|---|---|
| SRRK Scholar Rock Holding Corp | -1.25M | -11.5% | $68.75M | 10.84% |
| EWTX Edgewise Therapeutics, Inc. | -1.25M | -28.1% | $50.61M | 2.66% |
| RVMD Revolution Medicines, Inc. | -211.0K | -19.0% | $39.51M | 3.47% |
| KYMR Kymera Therapeutics, Inc. | -251.0K | -7.9% | $28.78M | 6.93% |
| GPCR Structure Therapeutics Inc. | -455.7K | -34.3% | $24.46M | 0.964% |
| RCUS Arcus Biosciences, Inc. | -586.6K | -19.5% | $18.09M | 1.54% |
| FULC Fulcrum Therapeutics, Inc. | -2.35M | -100.0% | $18.02M | Exited |
| WVE Wave Life Sciences, Inc. | -2.45M | -100.0% | $17.76M | Exited |
| NBIS Nebius Group N.V. | -61.6K | -54.2% | $17.02M | 0.296% |
| QURE uniQure N.V. | -1.00M | -100.0% | $16.35M | Exited |
| Holding | Shares | Trade Value | Weight |
|---|---|---|---|
| PBLS Parabilis Medicines, Inc. | +2.99M | $81.90M | 1.69% |
| ABVX Abivax S.A. | +576.0K | $76.76M | 1.58% |
| COAG Hemab Therapeutics Holdings, Inc. | +2.09M | $76.65M | 1.58% |
| RLAY Relay Therapeutics, Inc. | +3.65M | $68.29M | 1.41% |
| KLRA Kailera Therapeutics, Inc. | +2.21M | $48.78M | 1% |
| COF Capital One Financial Corp | +171.6K | $34.43M | 0.709% |
| ORKA Oruka Therapeutics, Inc. | +250.0K | $23.79M | 0.49% |
| SPTX Seaport Therapeutics, Inc. | +1.10M | $23.79M | 0.49% |
| TYRA Tyra Biosciences, Inc. | +725.0K | $23.16M | 0.477% |
| ADAG Adagene Inc. | +2.67M | $11.20M | 0.231% |
| Holding | Shares Sold | Trade Value | Prior Weight |
|---|---|---|---|
| FULC Fulcrum Therapeutics, Inc. | -2.35M | $18.02M | 0.516% |
| WVE Wave Life Sciences, Inc. | -2.45M | $17.76M | 0.509% |
| QURE uniQure N.V. | -1.00M | $16.35M | 0.468% |
| BCYC Bicycle Therapeutics Plc | -1.56M | $7.24M | 0.207% |
| FPS Forgent Power Solutions, Inc. | -100.0K | $2.93M | 0.084% |
| MU Micron Technology Inc | -6,000 | $2.03M | 0.058% |
| AS Amer Sports, Inc. | -50.0K | $1.65M | 0.047% |
| PRMB Primo Brands Corp | -50.0K | $941.50K | 0.027% |
| # | Activity | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1 | SRRK Scholar Rock Holding Corp | Healthcare | 9.58M | $526.63M | 10.84% | -1.25M | -11.5% | Reduced | 7.33% |
| 2 | KYMR Kymera Therapeutics, Inc. | Healthcare | 2.94M | $336.65M | 6.93% | -251.0K | -7.9% | Reduced | 2.99% |
| 3 | ERAS Erasca, Inc. | Healthcare | 11.40M | $208.81M | 4.3% | +153.5K | +1.4% | Added | 3.65% |
| 4 | MANE Veradermics, Inc | Healthcare | 1.66M | $203.51M | 4.19% | +150.0K | +10.0% | Added | 3.96% |
| 5 | TNGX Tango Therapeutics, Inc. | Healthcare | 6.18M | $193.17M | 3.98% | +522.3K | +9.2% | Added | 3.67% |
| 6 | RVMD Revolution Medicines, Inc. | Healthcare | 900.0K | $168.55M | 3.47% | -211.0K | -19.0% | Reduced | 0.42% |
| 7 | BCAX Bicara Therapeutics Inc. | Healthcare | 5.60M | $166.35M | 3.42% | -200.0K | -3.4% | Reduced | 8.25% |
| 8 | ARWR Arrowhead Pharmaceuticals, Inc. | Healthcare | 1.72M | $139.83M | 2.88% | +100.0K | +6.2% | Added | 1.2% |
| 9 | ONC BeOne Medicines Ltd. | Healthcare | 465.0K | $132.51M | 2.73% | 0 | 0.0% | Unchanged | 0.41% |
| 10 | EWTX Edgewise Therapeutics, Inc. | Healthcare | 3.18M | $129.39M | 2.66% | -1.25M | -28.1% | Reduced | 2.95% |
| 11 | RYTM Rhythm Pharmaceuticals, Inc. | Healthcare | 1.14M | $126.16M | 2.6% | +410.8K | +56.6% | Added | 1.65% |
| 12 | LXRX Lexicon Pharmaceuticals, Inc. | Healthcare | 44.30M | $106.33M | 2.19% | 0 | 0.0% | Unchanged | 9.91% |
| 13 | ELVN Enliven Therapeutics, Inc. | Healthcare | 1.77M | $90.05M | 1.85% | +1.03M | +137.8% | Added | 2.42% |
| 14 | SYRE Spyre Therapeutics, Inc. | Healthcare | 968.6K | $85.99M | 1.77% | +150.0K | +18.3% | Added | 1.14% |
| 15 | PBLS Parabilis Medicines, Inc. | Healthcare | 2.99M | $81.90M | 1.69% | +2.99M | – | New | 2.45% |
Tip. Select a row to see that position’s full history at Siren, L.L.C.
As of its Q2 2026 13F filing, Siren, L.L.C.’s five largest positions were Scholar Rock Holding Corp (SRRK) at 10.8%, Kymera Therapeutics, Inc. (KYMR) at 6.9%, Erasca, Inc. (ERAS) at 4.3%, Veradermics, Inc (MANE) at 4.2%, Tango Therapeutics, Inc. (TNGX) at 4.0% of the reported portfolio.
Siren, L.L.C. reported a 13F portfolio worth $4.86B across 111 positions for Q2 2026. That is up 39.2% from the previous quarter.
Its largest purchases by value were Parabilis Medicines, Inc. ($81.90M), Abivax S.A. ($76.76M), Hemab Therapeutics Holdings, Inc. ($76.65M). It opened 22 new positions.
Its largest sales by value were Scholar Rock Holding Corp ($68.75M), Edgewise Therapeutics, Inc. ($50.61M), Revolution Medicines, Inc. ($39.51M). It exited 8 positions entirely.
From the Form 13F-HR reports Siren, L.L.C. files with the SEC each quarter, within 45 days of quarter end. A 13F lists long positions in US-listed equities and options; it excludes short positions, cash, bonds and most non-US holdings.
13F data reflects long positions in US-listed equities and options as reported to the SEC up to 45 days after quarter end. It excludes short positions, cash, bonds and most non-US securities, so it is not a complete picture of a manager’s assets.