Bosch John Roderick Ten - 07 Nov 2025 Form 4 Insider Report for BillionToOne, Inc.

Role
Senior Vice President of Laboratory Operations
Signature
/s/ Thomas P. Lynch, Attorney-in-Fact
Issuer symbol
BLLN on Nasdaq
Transactions as of
07 Nov 2025
Net transactions value
+$48,000
Form type
4
Filing time
12 Nov 2025, 18:10:41 UTC
Previous filing
05 Nov 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
ten Bosch John Roderick Senior Vice President of Laboratory Operations C/O BILLIONTOONE, INC., 1035 O'BRIEN DRIVE, MENLO PARK /s/ Thomas P. Lynch, Attorney-in-Fact 12 Nov 2025 0002087126

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction BLLN Common Stock Other -37,000 -100% 0 07 Nov 2025 Direct F1
transaction BLLN Class A Common Stock Other +37,000 37,000 07 Nov 2025 Direct F1
transaction BLLN Class A Common Stock Purchase $48,000 +800 +2.2% $60.00* 37,800 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 -28,500 -100% 0 07 Nov 2025 Common Stock 28,500 $0.5600 Direct F1, F3
transaction BLLN Stock Option (right to buy) Other +28,500 28,500 07 Nov 2025 Class A Common Stock 28,500 $0.5600 Direct F1, F3
transaction BLLN Stock Option (right to buy) Other -20,000 -100% 0 07 Nov 2025 Common Stock 20,000 $2.80 Direct F1, F3
transaction BLLN Stock Option (right to buy) Other +20,000 20,000 07 Nov 2025 Class A Common Stock 20,000 $2.80 Direct F1, F3
transaction BLLN Stock Option (right to buy) Other -15,000 -100% 0 07 Nov 2025 Common Stock 15,000 $10.92 Direct F1, F4
transaction BLLN Stock Option (right to buy) Other +15,000 15,000 07 Nov 2025 Class A Common Stock 15,000 $10.92 Direct F1, F4
transaction BLLN Stock Option (right to buy) Other -30,000 -100% 0 07 Nov 2025 Common Stock 30,000 $15.17 Direct F1, F5
transaction BLLN Stock Option (right to buy) Other +30,000 30,000 07 Nov 2025 Class A Common Stock 30,000 $15.17 Direct F1, F5
transaction BLLN Stock Option (right to buy) Other -37,500 -100% 0 07 Nov 2025 Common Stock 37,500 $30.78 Direct F1, F6
transaction BLLN Stock Option (right to buy) Other +37,500 37,500 07 Nov 2025 Class A Common Stock 37,500 $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 fully vested and exercisable.
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 April 1, 2022, 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 May 15, 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:

Senior Vice President of Laboratory Operations