Siren, L.L.C.
- SEC CIK
- 0002005245
- Latest filing
- Aug 13, 2026
UPB holding history
Upstream Bio, Inc. in every 13F filed by Siren, L.L.C., including the quarters it was sold out or no filing was made. Changes compare share counts with the previous calendar quarter.
UPB overviewAll 13F holders of UPBFull Q2 2026 holdings
- Shares (Q1 2026)
- 0
- Sold out in Q1 2026
- Value
- $0
- % of portfolio
- 0.0%
- Quarters held
- 5
- Since Q4 2024
| Quarter | Shares | Value | % of portfolio | Share change | Action | All holders |
|---|---|---|---|---|---|---|
| Q1 2026 | 0 | $0 | 0.0% | −588,450−100.0% | Sold out | Holders |
| Q4 2025 | 588,450 | $16.0M | 0.5% | −200,000−25.4% | Reduced | Holders |
| Q3 2025 | 788,450 | $14.8M | 0.6% | 00.0% | Unchanged | Holders |
| Q2 2025 | 788,450 | $8.66M | 0.4% | 00.0% | Unchanged | Holders |
| Q1 2025 | 788,450 | $4.83M | 0.3% | −11,550−1.4% | Reduced | Holders |
| Q4 2024 | 800,000 | $13.2M | 0.6% | +800,000 | New | Holders |