Thomas P. Lynch - 07 Nov 2025 Form 4 Insider Report for BillionToOne, Inc.

Role
General Counsel, Chief Compliance Officer and Secretary
Signature
/s/ Thomas P. Lynch
Issuer symbol
BLLN on Nasdaq
Transactions as of
07 Nov 2025
Net transactions value
+$6,000
Form type
4
Filing time
12 Nov 2025, 18:16:47 UTC
Previous filing
05 Nov 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Lynch Thomas P. General Counsel, Chief Compliance Officer and Secretary C/O BILLIONTOONE, INC., 1035 O'BRIEN DRIVE, MENLO PARK /s/ Thomas P. Lynch 12 Nov 2025 0001659824

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction BLLN Common Stock Other -600 -100% 0 07 Nov 2025 Direct F1
transaction BLLN Class A Common Stock Other +600 600 07 Nov 2025 Direct F1
transaction BLLN Class A Common Stock Purchase $6,000 +100 +17% $60.00* 700 07 Nov 2025 Direct F2

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 -79,400 -100% 0 07 Nov 2025 Common Stock 79,400 $8.65 Direct F1, F3
transaction BLLN Stock Option (right to buy) Other +79,400 79,400 07 Nov 2025 Class A Common Stock 79,400 $8.65 Direct F1, F3
transaction BLLN Stock Option (right to buy) Other -15,000 -100% 0 07 Nov 2025 Common Stock 15,000 $11.55 Direct F1, F4
transaction BLLN Stock Option (right to buy) Other +15,000 15,000 07 Nov 2025 Class A Common Stock 15,000 $11.55 Direct F1, F4
transaction BLLN Stock Option (right to buy) Other -10,000 -100% 0 07 Nov 2025 Common Stock 10,000 $17.12 Direct F1, F5
transaction BLLN Stock Option (right to buy) Other +10,000 10,000 07 Nov 2025 Class A Common Stock 10,000 $17.12 Direct F1, F5
transaction BLLN Stock Option (right to buy) Other -40,000 -100% 0 07 Nov 2025 Common Stock 40,000 $30.78 Direct F1, F6
transaction BLLN Stock Option (right to buy) Other +40,000 40,000 07 Nov 2025 Class A Common Stock 40,000 $30.78 Direct F1, F6
* 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 (the "Offering").
F2 These shares of Class A common stock were purchased by the Reporting Person through a directed share program in connection with the Offering.
F3 The options are subject to a service-based vesting requirement, which shall be satisfied over a four-year period, with 25% of the options vesting on October 24, 2022. 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.
F4 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 October 1, 2023, subject to the Reporting Person's continuous service with the Issuer through each such vesting date.
F5 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 October 6, 2024, subject to the Reporting Person's continuous service with the Issuer through each such vesting date.
F6 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.

Remarks:

General Counsel, Chief Compliance Officer and Secretary