Flagship Pioneering, LLC

In its 13F for Q1 2025 (holdings as of March 31, 2025, filed May 15, 2025), Flagship Pioneering, LLC reported 4 stock positions worth $235.8 million. Its top holding was Moderna (MRNA) at 55.7% of the portfolio, followed by Foghorn Therapeutics (FHTX, 19.6%) and Sana Biotechnology (SANA, 17.8%). Compared with Q4 2024, it sold out of 1. The biggest sale was an exit from Omega Therapeutics (OMGAQ).

Most Recent 13F
Q2 2026
Location
CAMBRIDGE, MA
CIK
0001400240
Portfolio Value
$235.8M (Q1 2025)
SEC Filing
0000950123-25-005707 ↗ filed May 15, 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 $235.8M Q1 2025 Q2 2025: $268.5M Q2 2025 Q3 2025: $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 · $235.8M
MRNA Moderna Inc. 55.70% 4,632,149 $131.3M No change
FHTX Foghorn Therapeutics Inc. 19.62% 12,674,120 $46.3M No change
SANA Sana Biotechnology Inc. 17.82% 25,001,856 $42.0M No change
MCRB Seres Therapeutics Inc. 6.86% 23,117,045 $16.2M No change

Portfolio Sells Q4 2024 → Q1 2025
OMGAQ Omega Therapeutics Inc. Sold out 0.00% −6.52

Portfolio Buys Q4 2024 → Q1 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