Ross Taylor - 07 Nov 2025 Form 4 Insider Report for BillionToOne, Inc.

Role
Chief Financial Officer
Signature
/s/ Thomas P. Lynch, Attorney-in-Fact
Issuer symbol
BLLN on Nasdaq
Transactions as of
07 Nov 2025
Net transactions value
$0
Form type
4
Filing time
12 Nov 2025, 18:11:25 UTC
Previous filing
05 Nov 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Taylor Ross Chief Financial Officer C/O BILLIONTOONE, INC., 1035 O'BRIEN DRIVE, MENLO PARK /s/ Thomas P. Lynch, Attorney-in-Fact 12 Nov 2025 0002013346

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
transaction BLLN Stock Option (right to buy) Other -175,000 -100% 0 07 Nov 2025 Common Stock 175,000 $11.55 Direct F1, F2
transaction BLLN Stock Option (right to buy) Other +175,000 175,000 07 Nov 2025 Class A Common Stock 175,000 $11.55 Direct F1, F2
transaction BLLN Stock Option (right to buy) Other -75,000 -100% 0 07 Nov 2025 Common Stock 75,000 $30.78 Direct F1, F3
transaction BLLN Stock Option (right to buy) Other +75,000 75,000 07 Nov 2025 Class A Common Stock 75,000 $30.78 Direct F1, F3
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Pursuant to a reclassification exempt under Rule 16b-7, each share of Common Stock was automatically reclassified into one share of Class A common stock immediately prior to the completion of the Issuer's initial public offering of Class A common stock.
F2 The options are subject to a service-based vesting requirement, which shall be satisfied over a four-year period. Twenty-five percent of the options vested on January 8, 2025. The remaining 75% vest and become exercisable in equal monthly installments over the following three years, subject to the Reporting Person's continuous service with the Issuer through each such vesting date.
F3 The options are subject to a service-based vesting requirement, which shall be satisfied over a four-year period. The options vest and become exercisable in equal monthly installments commencing on September 15, 2025, subject to the Reporting Person's continuous service with the Issuer through each such vesting date.