Bain Capital Life Sciences Fund, L.P. - Aug 11, 2025 SCHEDULE 13D Report for X4 PHARMACEUTICALS, INC. Common Stock, par value $0.001 per share (XFOR)

Filing Manager
Bain Capital Life Sciences Fund, L.P.
Reporting Manager
Bain Capital Life Sciences Fund, L.P.
Security
X4 PHARMACEUTICALS, INC. Common Stock, par value $0.001 per share
Symbol
XFOR
Shares outstanding
24.4M shares
Disclosed Ownership
2.44M shares
Ownership
9.99%
Form type
SCHEDULE 13D
Date filed
8/13/2025, 09:40 PM
Date of event
Aug 11, 2025
Next filing
Sep 15, 2025
SEC
View on sec.gov

Reporting Managers (5)

Name Ownership Shares Owned sole voting power shared voting power Signature Title CIK
Bain Capital Life Sciences Fund, L.P. 9.99% 2.44M 0 2.44M /s/ Andrew Hack Andrew Hack, Partner of Bain Capital Life Sciences Investors, LLC 0001687968
Bain Capital Life Sciences Fund II, L.P. 9.99% 2.44M 0 2.44M /s/ Andrew Hack Andrew Hack, Partner of Bain Capital Life Sciences Investors, LLC 0001773187
BCIP Life Sciences Associates, LP 9.99% 2.44M 0 2.44M /s/ Andrew Hack Andrew Hack, Authorized Signatory of Boylston Coinvestors, LLC 0001702921
BCLS II Investco, LP 9.99% 2.44M 0 2.44M /s/ Andrew Hack Andrew Hack, Partner of Bain Capital Life Sciences Investors, LLC 0001818893
BCLS I Investco, LP 9.99% 2.44M 0 2.44M /s/ Andrew Hack Andrew Hack, Partner of Bain Capital Life Sciences Investors, LLC