BillionToOne, Inc. · Other acquisition · Class B Common Stock

What does this filing report?

An SEC Form 4 filing for BillionToOne, Inc. records an other acquisition involving Class B Common Stock on November 7, 2025. The reported quantity was 2,227,542. The filing date is November 12, 2025. This is one transaction record; amounts are not allocated among any joint reporting owners.

The acquisition category describes how securities were received. It does not by itself establish a cash purchase of common stock. Read the transaction code definitionsand the original filing before interpreting the amounts.

Derivative terms

Underlying security

Class A Common Stock

Underlying quantity

2,227,542

Conversion / exercise price

Not reported

Exercise date

Not reported

Expiration date

Not reported

Filing footnotes & remarks

F1

The total represents shares received upon conversion of shares of Series A-1 Convertible Preferred Stock.

F2

The reported security converted into the Issuer's Common Stock on a one-for-one basis automatically immediately prior to the closing of the Issuer's initial public offering of Class A common stock (the "Offering") without payment of further consideration. The shares have no expiration date.

F3

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 Offering.

F4

Represents shares held by the Reporting Person's spouse.

F5

Following the reclassification of Common Stock into Class A Common Stock, these shares of Class A common stock were exchanged at a 1:1 ratio for shares of Class B common stock in a transaction previously approved by the Issuer's board of directors.

F6

Each share of Class B Common Stock is convertible into one share of Class A common stock at the option of the holder. Class B common stock will convert automatically on a one-for-one basis into shares of the Issuer's Class A common stock upon the earliest of (i) seven years from the date of filing of the amended and restated certificate of incorporation, in connection with the Offering and (ii) the date specified by a vote of the holders of Class B common stock representing a majority of the outstanding shares of Class B common stock.

F7

The options are fully vested and exercisable.

F8

The options are subject to a service-based vesting requirement, which shall be satisfied over a six-year period. The options vest and become exercisable in equal monthly installments commencing on June 11, 2025, subject to the Reporting Person's continuous service with the Issuer through each such vesting date.

Footnotes are reproduced as plain text from the current source filing. For the full context, read the original SEC filing.