Flagship Pioneering, LLC
In its 13F for Q1 2026 (holdings as of March 31, 2026, filed May 15, 2026), Flagship Pioneering, LLC reported 5 stock positions worth $1.2 billion. Its top holding was Generate Biomedicines (GENB) at 67.4% of the portfolio, followed by Moderna (MRNA, 20.3%) and Sana Biotechnology (SANA, 6.2%). Compared with Q4 2025, it opened 1 new position. The biggest buy was a new position in Generate Biomedicines (GENB).
- Most Recent 13F
- Q2 2026
- Location
- CAMBRIDGE, MA
- CIK
- 0001400240
- Portfolio Value
- $1.2B (Q1 2026)
- SEC Filing
- 0001193125-26-226588 ↗ filed May 15, 2026
Holdings Value
Holdings 5 stocks · $1.2B
| GENB Generate Biomedicines Inc. | 67.44% | 62,673,117 | $783.4M | New |
| MRNA Moderna Inc. | 20.26% | 4,632,149 | $235.3M | No change |
| SANA Sana Biotechnology Inc. | 6.20% | 25,001,856 | $72.0M | No change |
| FHTX Foghorn Therapeutics Inc. | 5.22% | 12,674,120 | $60.6M | No change |
| MCRB Seres Therapeutics Inc. | 0.88% | 1,155,850 | $10.3M | No change |
Portfolio Sells Q4 2025 → Q1 2026
| None this quarter. | |||
Portfolio Buys Q4 2025 → Q1 2026
| GENB Generate Biomedicines Inc. | New | 67.44% | +67.44 |
All Filings
| Quarter | Positions | 13F Reported Value | Top Holdings |
|---|---|---|---|
| Q2 2026 | 5 | $1.5B | GENB, MRNA, SANA, FHTX, MCRB |
| Q1 2026 | 5 | $1.2B | GENB, MRNA, SANA, FHTX, MCRB |
| Q4 2025 | 4 | $324.0M | MRNA, SANA, FHTX, MCRB |
| Q3 2025 | 4 | $292.6M | MRNA, SANA, FHTX, MCRB |
| Q2 2025 | 4 | $268.5M | MRNA, SANA, FHTX, MCRB |
| Q1 2025 | 4 | $235.8M | MRNA, FHTX, SANA, MCRB |
| Q4 2024 | 5 | $334.2M | MRNA, FHTX, SANA, OMGAQ, MCRB |
| Q3 2024 | 6 | $591.9M | MRNA, FHTX, SANA, OMGAQ, MCRB |
| Q2 2024 | 6 | $843.4M | MRNA, SANA, FHTX, OMGAQ, MCRB |
| Q1 2024 | 7 | $1.5B | MRNA, SANA, OMGAQ, FHTX, DNLI |