1y return+86.7%S&P 500 +20.9%
3y return−43.5%S&P 500 +68.5%
5y return−76.9%S&P 500 +74.5%
These returns are for its stock picks as disclosed on Form 13F: last quarter's holdings, valued at this quarter's prices. They miss trades within each quarter, short positions, options, bonds, cash and fees, so they aren't the returns its clients got.
$100 invested in its stock picks
Since September 30, 2016: $68 against $345 in the S&P 500.2
Flagship Pioneering, LLCS&P 500 (SPY)
Top holdings
At the end of June 30, 2026. Change is in shares since the quarter before.2
| Stock | Value | Share of portfolio | Change |
|---|---|---|---|
| GENBGenerate Biomedicines Inc | $1.1B | 68.7% | |
| MRNAModerna Inc | $324.4M | 21.1% | |
| SANASana Biotechnology Inc | $87.3M | 5.7% | |
| FHTXFoghorn Therapeutics Inc | $61.8M | 4.0% | |
| MCRBSeres Therapeutics Inc | $9.1M | 0.6% |
Best picks still held
How each current holding has done since the quarter it first appeared in its filings (up to six years back).
| Stock | Held since | Return since | Now worth |
|---|---|---|---|
| GENBGenerate Biomedicines Inc | March 31, 2026 | +35.0% | $1.1B |
| MRNAModerna Inc | June 30, 2020 | +9.1% | $324.4M |
| MCRBSeres Therapeutics Inc | June 30, 2025 | −29.0% | $9.1M |
| FHTXFoghorn Therapeutics Inc | December 31, 2020 | −75.9% | $61.8M |
| SANASana Biotechnology Inc | March 31, 2021 | −89.6% | $87.3M |
Quarter by quarter
| Quarter | Its picks | S&P 500 |
|---|---|---|
| June 30, 2026 | +32.6% | +14.8% |
| March 31, 2026 | +16.7% | −4.6% |
| December 31, 2025 | +10.7% | +2.4% |
| September 30, 2025 | +9.0% | +7.8% |
| June 30, 2025 | +16.4% | +10.5% |
| March 31, 2025 | −24.5% | −4.6% |
| December 31, 2024 | −43.3% | +2.1% |
| September 30, 2024 | −29.8% | +5.4% |
| June 30, 2024 | −3.4% | +4.0% |
| March 31, 2024 | +16.5% | +10.0% |
| December 31, 2023 | −0.4% | +11.2% |
| September 30, 2023 | −22.9% | −3.6% |
| June 30, 2023 | −13.1% | +8.3% |
| March 31, 2023 | −12.2% | +7.0% |
| December 31, 2022 | +27.0% | +7.1% |
| September 30, 2022 | −12.6% | −5.3% |
| June 30, 2022 | −19.7% | −16.5% |
| March 31, 2022 | −34.4% | −4.9% |
| December 31, 2021 | −32.2% | +10.7% |
| September 30, 2021 | +35.1% | +0.3% |
Sources
Every number on this page points here. Each one links to the public record.
- 1SEC EDGAR: Flagship Pioneering, LLC Form 13F filingshttps://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=1400240&type=13F-HR&dateb=&owner=include&count=40CIK 1400240
- 2SEC: 13F for the quarter ended June 30, 2026https://www.sec.gov/Archives/edgar/data/1400240/000119312526352122/Filed August 14, 2026 · accession 0001193125-26-352122