David Tsao - 05 Nov 2025 Form 3 Insider Report for BillionToOne, Inc.

Role
Chief Technology Officer, Director
Signature
/s/ Thomas P. Lynch, Attorney-in-Fact
Issuer symbol
BLLN on Nasdaq
Transactions as of
05 Nov 2025
Net transactions value
$0
Form type
3
Filing time
05 Nov 2025, 21:30:05 UTC
Next filing
12 Nov 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Tsao David Chief Technology Officer, Director C/O BILLIONTOONE, INC., 1035 O'BRIEN DRIVE, MENLO PARK /s/ Thomas P. Lynch, Attorney-in-Fact 05 Nov 2025 0002087127

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
holding BLLN Common Stock 2,325,108 05 Nov 2025 Direct F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
holding BLLN Stock Option (right to buy) 05 Nov 2025 Common Stock 640,000 $2.80 Direct F2, F4
holding BLLN Stock Option (right to buy) 05 Nov 2025 Common Stock 501,551 $20.04 Direct F3, F4
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Immediately prior to the completion of the Issuer's initial public offering of Class A common stock (the "Offering"), each share of Common Stock shall be reclassified into one share of Class A common stock and such shares of Class A common stock shall be exchanged at a 1:1 ratio for shares of Class B common stock.
F2 The options are fully vested and exercisable.
F3 The options are subject to a service-based vesting requirement, which shall be satisfied over a six-year period. The options vest and become exercisable in equal monthly installments commencing on June 11, 2025, subject to the Reporting Person's continuous service with the Issuer through each such vesting date.
F4 Immediately prior to the completion of the Issuer's Offering, each share of Common Stock shall be reclassified into one share of Class A common stock.

Remarks:

Exhibit 24 - Power of Attorney