Key facts
- This page summarizes David Tsao's Form 4 filing for BillionToOne, Inc..
- 9 reported transactions and 5 derivative rows are listed below.
- Accepted by SEC: 12 Nov 2025, 18:12.
David Tsao - 07 Nov 2025 Form 4 Insider Report for BillionToOne, Inc.
- Reporting relationship
- Chief Technology Officer, Director
- Issuer ticker
- BLLN on Nasdaq
- Reported as of
- 07 Nov 2025
- Net transaction value
- +$60,000
- SEC form
- 4
- Accepted by SEC
- 12 Nov 2025, 18:12:51 UTC
- Prior SEC filing
- 05 Nov 2025
- Next SEC filing
- 17 Jun 2026
- Source filing
- View source filing
- Reporting owner signature
- /s/ Thomas P. Lynch, Attorney-in-Fact
Source evidence
Original filing metadata and source links for verification.
5 source fields
Reporting owner
1 detail
Key filing fact
David Tsao filed Form 4 for BillionToOne, Inc. on 12 Nov 2025.
Change
- Previous filing in this sequence was filed on 05 Nov 2025.
- Current net transaction value: +$60,000.
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
View source filing
Ownership activity is grounded in SEC Form 4 disclosures.
Reporting Owners (1)
CIK 0002087127
Primary reporting owner
Tsao David
- Relationship
- Chief Technology Officer, Director
- 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 non-derivative transactions
Shares, units, or other non-derivative securities reported in this filing.
BLLN
transaction
Common Stock
Other
- Transaction value
- Shares
- -2,325,108
- Change %
- -100%
- Price
- Shares after
- 0
- Date
- 07 Nov 2025
- Ownership
- Direct
- Footnotes
- F1
BLLN
transaction
Class A Common Stock
Other
- Transaction value
- Shares
- +2,325,108
- Change %
- Price
- Shares after
- 2,325,108
- Date
- 07 Nov 2025
- Ownership
- Direct
- Footnotes
- F1
BLLN
transaction
Class A Common Stock
Other
- Transaction value
- Shares
- -2,325,108
- Change %
- -100%
- Price
- Shares after
- 0
- Date
- 07 Nov 2025
- Ownership
- Direct
- Footnotes
- F2
BLLN
transaction
Class A Common Stock
Purchase
- Transaction value
- $60,000
- Shares
- +1,000
- Change %
- Price
- $60.00*
- Shares after
- 1,000
- Date
- 07 Nov 2025
- Ownership
- Direct
- Footnotes
- F3
Reported derivative securities
Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.
BLLN
transaction
Derivative
Class B Common Stock
Other
- Transaction value
- $0
- Shares
- +2,325,108
- Change %
- Price
- $0.000000
- Shares after
- 2,325,108
- Date
- 07 Nov 2025
- Ownership
- Direct
- Underlying class
- Class A Common Stock
- Underlying amount
- 2,325,108
- Exercise price
- Footnotes
- F2, F4
BLLN
transaction
Derivative
Stock Option (right to buy)
Other
- Transaction value
- Shares
- -640,000
- Change %
- -100%
- Price
- Shares after
- 0
- Date
- 07 Nov 2025
- Ownership
- Direct
- Underlying class
- Common Stock
- Underlying amount
- 640,000
- Exercise price
- $2.80
- Footnotes
- F1, F5
BLLN
transaction
Derivative
Stock Option (right to buy)
Other
- Transaction value
- Shares
- +640,000
- Change %
- Price
- Shares after
- 640,000
- Date
- 07 Nov 2025
- Ownership
- Direct
- Underlying class
- Class A Common Stock
- Underlying amount
- 640,000
- Exercise price
- $2.80
- Footnotes
- F1, F5
BLLN
transaction
Derivative
Stock Option (right to buy)
Other
- Transaction value
- Shares
- -501,551
- Change %
- -100%
- Price
- Shares after
- 0
- Date
- 07 Nov 2025
- Ownership
- Direct
- Underlying class
- Common Stock
- Underlying amount
- 501,551
- Exercise price
- $20.04
- Footnotes
- F1, F6
BLLN
transaction
Derivative
Stock Option (right to buy)
Other
- Transaction value
- Shares
- +501,551
- Change %
- Price
- Shares after
- 501,551
- Date
- 07 Nov 2025
- Ownership
- Direct
- Underlying class
- Class A Common Stock
- Underlying amount
- 501,551
- Exercise price
- $20.04
- Footnotes
- F1, F6
* marks a reported price that did not pass the local price check.
Additional SEC filing notes
Filing notes and footnotes
Explanation of responses 6 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 (the "Offering").
Footnote F2
Following the reclassification of Common Stock into Class A Common Stock, the 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.
Footnote F3
These shares of Class A common stock were purchased by the Reporting Person through a directed share program in connection with the Offering.
Footnote F4
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.
Footnote F5
The options are fully vested and exercisable.
Footnote F6
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.