Siren, L.L.C.
Siren, L.L.C. reported 115 stocks worth $4.9B in its 13F filing for Q2 2026, filed Aug 13, 2026. Its largest holdings are SRRK (10.7%), KYMR (6.8%) and ERAS (4.2%). Compared with Q1 2026, the fund opened new positions in PBLS, ABVX and COAG, added to ERAS, MANE and TNGX, trimmed SRRK, KYMR and RVMD and sold out of FULC, WVE and QURE.
Holdings
| # | Stock | Value | Weight | Shares | Change | Shares, 8 qtrs | Held |
|---|---|---|---|---|---|---|---|
| 1 |  SRRK Scholar Rock Hldg Corp | $527M | 10.7% | 9.6M | −1.3M (−12%) | 8 of 8 | |
| 2 |  KYMR Kymera Therapeutics Inc | $337M | 6.8% | 2.9M | −251K (−8%) | 8 of 8 | |
| 3 |  ERAS Erasca Inc | $209M | 4.2% | 11.4M | +154K (+1%) | 8 of 8 | |
| 4 |  MANE Veradermics Inc | $204M | 4.1% | 1.7M | +150K (+10%) | 2 of 8 | |
| 5 |  TNGX Tango Therapeutics Inc | $193M | 3.9% | 6.2M | +522K (+9%) | 8 of 8 | |
| 6 |  RVMD Revolution Medicines Inc | $169M | 3.4% | 900K | −211K (−19%) | 8 of 8 | |
| 7 |  BCAX Bicara Therapeutics Inc | $166M | 3.4% | 5.6M | −200K (−3%) | 8 of 8 | |
| 8 |  ARWR Arrowhead Pharmaceuticals in | $140M | 2.8% | 1.7M | +100K (+6%) | 8 of 8 | |
| 9 |  ONC Beone Medicines Ltd | $133M | 2.7% | 465K | No change | 8 of 8 | |
| 10 |  EWTX Edgewise Therapeutics Inc | $129M | 2.6% | 3.2M | −1.2M (−28%) | 8 of 8 |
Positions at Jun 30, 2026, as reported. Change is against the fund's Q1 2026 filing; weight is the share of the fund's reported stocks.
Sold out
held in Q1 2026, gone in Q2 2026| Stock | Value last quarter | Shares sold |
|---|---|---|
CENTESSA PHARMACEUTICALS PLC | $41.8M | 1.1M |
ENGENE HOLDINGS INC | $35.8M | 5.3M |
 FULC Fulcrum Therapeutics Inc | $18M | 2.4M |
 WVE Wave Life Sciences Ltd | $17.8M | 2.5M |
 QURE Uniqure NV | $16.4M | 1M |
🔒 Free account: see all 10.
Options
valued at the underlying shares
Reported value
last 8 quartersThe value of the US stocks the fund reported, at quarter end prices. It moves with the market as well as with buying and selling.
Filings for Q2 2026
straight from the SEC| Filed | Form | Quarter | |
|---|---|---|---|
| Aug 13, 2026 | 13F-HR | Q2 2026 | SEC filing ↗ |
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All hedge fund holdings →Siren, L.L.C. 13F FAQ
What does Siren, L.L.C. own?
Siren, L.L.C. reported 115 stocks worth $4.9B in its 13F filing for Q2 2026, filed Aug 13, 2026. The table above lists every position in the filing (the top 10 without an account).
What did Siren, L.L.C. buy and sell in Q2 2026?
Compared with Q1 2026: 25 new positions, 31 added to, 21 trimmed and 10 sold out. New positions include PBLS, ABVX and COAG. It sold all of FULC, WVE and QURE.
When will Siren, L.L.C. file its next 13F?
Holdings as of Sep 30, 2026 are due by Nov 16, 2026. The filing appears on this page within minutes of reaching the SEC.
How much is Siren, L.L.C.'s portfolio worth?
The Q2 2026 filing reports $4.9B in US stocks. That leaves out cash, bonds, short positions and most foreign holdings, so the fund's total assets are usually larger.
For informational and educational purposes only. Not investment advice, and not a recommendation to buy or sell any security. Holdings come from the fund's SEC Form 13F filings as reported and show positions at the end of the quarter, up to 45 days before the filing. The fund may have changed its positions since. A 13F leaves out short positions, cash, bonds and most foreign holdings. See all hedge fund holdings.