X0508 4 2025-11-07 0002070849 BillionToOne, Inc. BLLN 0002087877 Rai Akshay 2180 SAND HILL ROAD, STE. 100 MENLO PARK CA 94025 true false false false false Class A Common Stock 2025-11-07 4 P false 2500 60 A 13509 D Class A Common Stock 1784414 I See footnote The reported securities are directly held by Wipro Enterprises Private Limited (Wipro), of which Mr. Rai is the nominee/investor director appointed by Wipro Enterprises Limited. Mr. Rai will not have voting or dispositive control of these securities while such securities are held by Wipro and thus disclaims beneficial ownership of such securities. /s/ Thomas P. Lynch, Attorney-in-Fact 2025-11-12