Thomas P. Lynch - 13 Oct 2026 Form 4 Insider Report for BillionToOne, Inc. (BLLN)

Reporting relationship: General Counsel, Chief Compliance Officer and Secretary
Issuer ticker: BLLN
Reported as of: 13 Oct 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 19 Oct 2026, 19:35:12 UTC
Prior SEC filing: 13 Oct 2026
Source filing: View source filing
Reporting owner signature: Thomas P. Lynch

Filing notes and source

Key filing fact

Thomas P. Lynch filed Form 4 for BillionToOne, Inc. (BLLN) on 19 Oct 2026.

Key facts

This page summarizes Thomas P. Lynch's Form 4 filing for BillionToOne, Inc. (BLLN).
2 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 19 Oct 2026, 19:35.

Change

Previous filing in this sequence was filed on 13 Oct 2026.
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 0001659824 Primary reporting owner

Lynch Thomas P.

Relationship: General Counsel, Chief Compliance Officer and Secretary
Address: C/O BILLIONTOONE, INC., 1035 O'BRIEN DRIVE, MENLO PARK
Signature: Thomas P. Lynch
Signature date: 19 Oct 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

BLLN transaction

Class A Common Stock

Options Exercise

Transaction value
Shares: +2,000
Change %: +23%
Price: $8.65^*
Shares after: 10,700
Date: 13 Oct 2026
Ownership: Direct

Reported derivative securities

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

BLLN transaction Derivative

Stock Option (right to buy)

Options Exercise

Transaction value
Shares: -2,000
Change %: -4.9%
Price: $8.65^*
Shares after: 38,974
Date: 13 Oct 2026
Ownership: Direct
Underlying class: Class A Common Stock
Underlying amount: 2,000
Exercise price: $8.65
Footnotes: F1

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

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 1 footnote

Footnote F1

The options are fully vested and exercisable. The terms of the underlying option grant are as previously reported on the Reporting Person's Form 3 filed on November 5, 2025.

SEC remarks

General Counsel, Chief Compliance Officer and Secretary