David Tsao - 31 Dec 2025 SCHEDULE 13G Report for BillionToOne, Inc. Class A common stock, par value $0.00001 per share (BLLN)

Filing Manager: David Tsao
Reporting Manager: David Tsao
Security: BillionToOne, Inc. Class A common stock, par value $0.00001 per share
Symbol: BLLN
Shares outstanding: 43,996,623 shares
Disclosed Ownership: 3,035,767 shares
Ownership: 6.9%
Form type: SCHEDULE 13G
Filing time: 17 Feb 2026, 17:00:11 UTC
Date of event: 31 Dec 2025
SEC: View on sec.gov

Reporting Managers (1)

Name	Ownership	Shares Owned	sole voting power	shared voting power	Signature	Title	CIK
David Tsao	6.9%	3,035,767	3,035,767	0	/s/ Thomas Lynch, Attorney-in-fact	Thomas Lynch, Attorney-in-fact