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

Reporting relationship: Chief Financial Officer
Issuer ticker: BLLN on Nasdaq
Reported as of: 07 Nov 2025
Net transaction value: $0
SEC form: 4
Accepted by SEC: 12 Nov 2025, 18:11:25 UTC
Prior SEC filing: 05 Nov 2025
Next SEC filing: 24 Mar 2026
Source filing: View source filing
Reporting owner signature: /s/ Thomas P. Lynch, Attorney-in-Fact

Key filing fact

Ross Taylor filed Form 4 for BillionToOne, Inc. on 12 Nov 2025.

Key facts

This page summarizes Ross Taylor's Form 4 filing for BillionToOne, Inc..
4 reported transactions and 4 derivative rows are listed below.
Accepted by SEC: 12 Nov 2025, 18:11.

Change

Previous filing in this sequence was filed on 05 Nov 2025.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0002013346 Primary reporting owner

Taylor Ross

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

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

BLLN transaction Derivative

Stock Option (right to buy)

Other

Transaction value
Shares: -175,000
Change %: -100%
Price
Shares after: 0
Date: 07 Nov 2025
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 175,000
Exercise price: $11.55
Footnotes: F1, F2

BLLN transaction Derivative

Stock Option (right to buy)

Other

Transaction value
Shares: +175,000
Change %
Price
Shares after: 175,000
Date: 07 Nov 2025
Ownership: Direct
Underlying class: Class A Common Stock
Underlying amount: 175,000
Exercise price: $11.55
Footnotes: F1, F2

BLLN transaction Derivative

Stock Option (right to buy)

Other

Transaction value
Shares: -75,000
Change %: -100%
Price
Shares after: 0
Date: 07 Nov 2025
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 75,000
Exercise price: $30.78
Footnotes: F1, F3

BLLN transaction Derivative

Stock Option (right to buy)

Other

Transaction value
Shares: +75,000
Change %
Price
Shares after: 75,000
Date: 07 Nov 2025
Ownership: Direct
Underlying class: Class A Common Stock
Underlying amount: 75,000
Exercise price: $30.78
Footnotes: F1, F3

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 3 footnotes

Footnote 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.

Footnote 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.

Footnote 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.