Flagship Ventures Fund V, L.P. - 09 Jan 2026 SCHEDULE 13D/A Report for FOGHORN THERAPEUTICS INC. Common Stock, $0.0001 par value per share (FHTX)

Filing Manager
Flagship Ventures Fund V, L.P.
Reporting Manager
Noubar Afeyan
Security
FOGHORN THERAPEUTICS INC. Common Stock, $0.0001 par value per share
Symbol
FHTX
Shares outstanding
76,378,254 shares
Disclosed Ownership
20,774,885 shares
Ownership
27%
Form type
SCHEDULE 13D/A
Filing time
13 Jan 2026, 17:09:10 UTC
Date of event
09 Jan 2026
SEC
View on sec.gov

Reporting Managers (10)

Name Ownership Shares Owned sole voting power shared voting power Signature Title CIK
Flagship Ventures Fund V, L.P. 16% 9,330,878 0 9,330,878 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Manager of General Partner 0001627639
Flagship Ventures Fund V General Partner LLC 16% 9,330,878 0 9,330,878 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Manager
Flagship Ventures Opportunities Fund I, L.P. 2.5% 1,491,441 0 1,491,441 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Manager of General Partner
Flagship Ventures Opportunities Fund I General Partner LLC 2.5% 1,491,441 0 1,491,441 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Manager
Flagship Pioneering Special Opportunities Fund II, L.P. 3.2% 3,666,715 0 3,666,715 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Sole Member and Manager of Manager of Manager of General Partner
Flagship Pioneering Special Opportunities Fund II General Partner LLC 3.2% 3,666,715 0 3,666,715 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Sole Member and Manager of Manager of Manager
Flagship Pioneering Fund VII, L.P. 7.1% 6,285,851 0 6,285,851 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Sole Member and Manager of Manager of Manager of General Partner
Flagship Pioneering Fund VII General Partner LLC 7.1% 6,285,851 0 6,285,851 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Sole Member and Manager of Manager of Manager
Flagship Pioneering, LLC 10% 9,952,566 0 9,952,566 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D., Sole Member and Manager of Manager
Noubar Afeyan 27% 20,774,885 0 20,774,885 /s/ Noubar B. Afeyan, Ph.D. Noubar B. Afeyan, Ph.D.