Flagship Pioneering, LLC

In its 13F for Q3 2025 (holdings as of September 30, 2025, filed November 14, 2025), Flagship Pioneering, LLC reported 4 stock positions worth $292.6 million. Its top holding was Moderna (MRNA) at 40.9% of the portfolio, followed by Sana Biotechnology (SANA, 30.3%) and Foghorn Therapeutics (FHTX, 21.2%). Its holdings were unchanged from Q2 2025.

Most Recent 13F
Q2 2026
Location
CAMBRIDGE, MA
CIK
0001400240
Portfolio Value
$292.6M (Q3 2025)
SEC Filing
0001193125-25-282859 ↗ filed Nov 14, 2025

Holdings Value

0$500.0M$1.0B$1.5B$2.0B Q1 2024: $1.5B Q1 2024 Q2 2024: $843.4M Q2 2024 Q3 2024: $591.9M Q3 2024 Q4 2024: $334.2M Q4 2024 Q1 2025: $235.8M Q1 2025 Q2 2025: $268.5M Q2 2025 Q3 2025: $292.6M $292.6M Q3 2025 Q4 2025: $324.0M Q4 2025 Q1 2026: $1.2B Q1 2026 Q2 2026: $1.5B Q2 2026

Holdings 4 stocks · $292.6M
MRNA Moderna Inc. 40.89% 4,632,149 $119.6M No change
SANA Sana Biotechnology Inc. 30.33% 25,001,856 $88.8M No change
FHTX Foghorn Therapeutics Inc. 21.18% 12,674,120 $62.0M No change
MCRB Seres Therapeutics Inc. 7.60% 1,155,850 $22.2M No change

Portfolio Sells Q2 2025 → Q3 2025
None this quarter.

Portfolio Buys Q2 2025 → Q3 2025
None this quarter.

All Filings

QuarterPositions13F Reported ValueTop Holdings
Q2 2026 5$1.5BGENB, MRNA, SANA, FHTX, MCRB
Q1 2026 5$1.2BGENB, MRNA, SANA, FHTX, MCRB
Q4 2025 4$324.0MMRNA, SANA, FHTX, MCRB
Q3 2025 4$292.6MMRNA, SANA, FHTX, MCRB
Q2 2025 4$268.5MMRNA, SANA, FHTX, MCRB
Q1 2025 4$235.8MMRNA, FHTX, SANA, MCRB
Q4 2024 5$334.2MMRNA, FHTX, SANA, OMGAQ, MCRB
Q3 2024 6$591.9MMRNA, FHTX, SANA, OMGAQ, MCRB
Q2 2024 6$843.4MMRNA, SANA, FHTX, OMGAQ, MCRB
Q1 2024 7$1.5BMRNA, SANA, OMGAQ, FHTX, DNLI