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Flagship Pioneering, LLC

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13F filer, CIK 1400240, CAMBRIDGE, MA

Flagship Pioneering, LLC reported $292,619,998 across 4 holdings for the quarter ended 2025-09-30, in a 13F-HR filed 2025-11-14.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0001193125-25-282859

Period
2025-09-30
Reported value
$293M
Holdings
4
Top 10 weight
100%
New
0
Sold out
0

Part of the filer group Flagship Pioneering, LLC

How groups are built

Holdings, Q3 2025

Share positions as resolved from 13F-HR 0001193125-25-282859, largest first. % of portfolio is the value over $292,619,998, the sum of the share positions whose value is usable for ratios (method).

SecurityHistorySharesValue% of portfolioChangeLatest eventTimeline
MRNAMODERNA INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 4,632,149 shares; 2024Q4: 4,632,149 shares; 2025Q1: 4,632,149 shares; 2025Q2: 4,632,149 shares; 2025Q3: 4,632,149 shares 4,632,149$120M40.89%0Timeline
SANASANA BIOTECHNOLOGY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 25,001,856 shares; 2024Q4: 25,001,856 shares; 2025Q1: 25,001,856 shares; 2025Q2: 25,001,856 shares; 2025Q3: 25,001,856 shares 25,001,856$88.8M30.33%0Timeline
FHTXFOGHORN THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 12,674,120 shares; 2024Q4: 12,674,120 shares; 2025Q1: 12,674,120 shares; 2025Q2: 12,674,120 shares; 2025Q3: 12,674,120 shares 12,674,120$62M21.18%0Timeline
MCRBSERES THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 1,155,850 shares; 2025Q3: 1,155,850 shares 1,155,850$22.2M7.6%0Timeline

How Q3 2025 was built

Available 13F filings of this filer for the quarter and their roles: the base report is the latest original or restatement, NEW HOLDINGS amendments filed after it are added (method).

FilingRoleAmendmentFiledAcceptedIngested
13F-HR 0001193125-25-282859 base2025-11-14acceptance time not in the bulk data set