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Flagship Pioneering, LLC

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13F filer, CIK 1400240, CAMBRIDGE, MA

Flagship Pioneering, LLC reported $268,465,915 across 4 holdings for the quarter ended 2025-06-30, in a 13F-HR filed 2025-08-14.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0000950123-25-008304

Period
2025-06-30
Reported value
$268M
Holdings
4
Top 10 weight
100%
New
1
Sold out
1

Part of the filer group Flagship Pioneering, LLC

How groups are built

Largest buys vs the previous quarter

SecurityShares changeApprox. value
MCRBnew+1,155,850$12.8M

Ranked by the share change valued at this quarter's implied price (value over shares in the 13F). A position sold out is valued at the previous quarter's price, its last report.

Largest sells vs the previous quarter

SecurityShares changeApprox. value
SERES THERAPEUTICS INCexited-23,117,045-$16.2M

Ranked by the share change valued at this quarter's implied price (value over shares in the 13F). A position sold out is valued at the previous quarter's price, its last report.

Holdings, Q2 2025

Share positions as resolved from 13F-HR 0000950123-25-008304, largest first. % of portfolio is the value over $268,465,915, 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; 2023Q3: restricted; 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 4,632,149$128M47.6%0Timeline
SANASANA BIOTECHNOLOGY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 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 25,001,856$68.3M25.42%0Timeline
FHTXFOGHORN THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 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 12,674,120$59.6M22.19%0Timeline
MCRBSERES THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 1,155,850 shares 1,155,850$12.8M4.78%newTimeline

Sold out in Q2 2025

Positions in the previous quarter's report that this quarter's report no longer lists.

SecurityShares beforeValue beforeType
SERES THERAPEUTICS INCSERES THERAPEUTICS INC23,117,045$16.2Mshares

How Q2 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 0000950123-25-008304 base2025-08-14acceptance time not in the bulk data set