Flagship Pioneering, LLC
Exempt adviserRegulatory profile
From Form ADV, the SEC filer profile, 13D/13G type codes and N-CEN, never from the name.
| Rosters | Regulatory AUM | Main clients |
|---|---|---|
| Apr 2025 to Dec 2025 | — | — |
| Apr 2024 to Mar 2025 | — | — |
| Jun 2023 to Mar 2024 | — | — |
| May 2023 | $0 | — |
| Dec 2019 to Apr 2023 | — | — |
Portfolio style
Measured from the filed 13F common-share book for Jun 30, 2026, never from the firm's own description.
Closest benchmark: the Russell 2000 as of 2026-06-30, active share 100.0%; sector active share 90.6% against the combined 13F book's sector weights.
Over time 26 measured quarters
How the bands are measured
Style bands measure the filed 13F common-share book each closed quarter, tested in this order. Unknown: under $10,000,000 of valued equity or 5 stocks. Index-like (100+ stocks): active share of 20% or less against the closest benchmark, which is the S&P 500, S&P MidCap 400, S&P SmallCap 600, Russell 1000, Russell 2000, Nasdaq-100 or Dow Jones Industrial Average (weighted by an index-tracking fund's reported holdings or the index's constituents nearest the quarter end, over the names resolved to companies, and only when those are 90%+ of its weight) or every 13F filer's combined book, or index series holding 80%+ of the registered fund assets it advises (N-CEN) and equal to 50%+ of its book. Systematic-like: 500+ stocks, 100%+ annual turnover and a top 10 weight of 25% or less. Concentrated: a top 10 weight of 60%+ or 12 or fewer effective positions. Diversified active: none of these. Turnover is the smaller of buys and sells over average equity value, summed over four quarters: low under 30%, high 100%+. Horizon is the value-weighted number of quarters each position has been held: short under 4, long 12+.
Clone Performance
Build a hypothetical price-return history from this filer's public 13F holdings.
View clone backtestPortfolio Concentration
5 tracked positions · as of Jun 30, 2026 · Δ vs Mar 31, 2026Portfolio Trend
Sector Breakdown
As of Jun 30, 2026| Sector | % Portfolio | Value |
|---|---|---|
| Healthcare | 100.0% | $1,539,910,714 |
Last Quarter's Activity
Export CSVAdded To
Positions the filer increasedTrimmed
Positions the filer reducedNew Positions
Positions the filer opened this quarterSold Out
Positions the filer fully exited| Ticker | Company | Type | Shares | Value (USD) | % of Portfolio | History |
|---|---|---|---|---|---|---|
| GENB |
Generate Biomedicines, Inc.
Healthcare
|
Held | 62,673,117 | $1,057,295,483 | 68.66% | |
| MRNA |
Moderna, Inc.
Healthcare
|
Held | 4,632,149 | $324,389,393 | 21.07% | |
| SANA |
Sana Biotechnology, Inc.
Healthcare
|
Held | 25,001,856 | $87,256,477 | 5.67% | |
| FHTX |
Foghorn Therapeutics Inc.
Healthcare
|
Held | 12,674,120 | $61,849,705 | 4.02% | |
| MCRB |
Seres Therapeutics, Inc.
Healthcare
|
Held | 1,155,850 | $9,119,656 | 0.59% |
Covers the securities this platform tracks: U.S.-listed common stock and the put/call positions reported on it. A 13F can also report security types outside that coverage — preferred shares, bonds, warrants, untracked share classes — so the filing's own declared total can exceed the figures above. The source filing is linked at the top of this table.