Skip to content
Disclosery

Flagship Pioneering, LLC

Follow

13F filer, CIK 1400240, CAMBRIDGE, MA

Flagship Pioneering, LLC reported $1,161,567,162 across 5 holdings for the quarter ended 2026-03-31, in a 13F-HR filed 2026-05-15.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0001193125-26-226588

Period
2026-03-31
Reported value
$1.16B
Holdings
5
Top 10 weight
100%
New
1
Sold out
0

Part of the filer group Flagship Pioneering, LLC

How groups are built

Largest buys vs the previous quarter

SecurityShares changeApprox. value
GENBnew+62,673,117$783M

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

None.

Holdings, Q1 2026

Share positions as resolved from 13F-HR 0001193125-26-226588, largest first. % of portfolio is the value over $1,161,567,162, the sum of the share positions whose value is usable for ratios (method).

SecurityHistorySharesValue% of portfolioChangeLatest eventTimeline
GENBGENERATE BIOMEDICINES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: not reported; 2026Q1: 62,673,117 shares 62,673,117$783M67.44%newTimeline
MRNAMODERNA INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 4,632,149 shares; 2026Q1: 4,632,149 shares 4,632,149$235M20.26%0Timeline
SANASANA BIOTECHNOLOGY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 25,001,856 shares; 2026Q1: 25,001,856 shares 25,001,856$72M6.2%0Timeline
FHTXFOGHORN THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 12,674,120 shares; 2026Q1: 12,674,120 shares 12,674,120$60.6M5.22%0Timeline
MCRBSERES THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 1,155,850 shares; 2025Q3: 1,155,850 shares; 2025Q4: 1,155,850 shares; 2026Q1: 1,155,850 shares 1,155,850$10.3M0.88%0Timeline

How Q1 2026 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 0001193125-26-226588 base2026-05-15acceptance time not in the bulk data set