BillionToOne officer plans $1.98M stock sale

Officer Thomas P. Lynch files a Rule 144 notice to sell 20,000 BillionToOne Class A shares following a stock option exercise.

Rhea-AI Filing Summary

BillionToOne, Inc. (BLLN) received a notice under Rule 144 for a proposed sale of Class A shares by officer Thomas P. Lynch. The notice covers a planned sale of 20,000 Class A shares, with an indicated aggregate market value of $1,984,800 and reference outstanding shares of 42,644,388 as of the stated date.

The shares are expected to be sold through Fidelity Brokerage Services LLC on NASDAQ on or after September 8, 2026, in connection with a stock option exercise for cash with the issuer as the counterparty.

Key Figures

Shares to be sold: 20,000 shares Aggregate market value: $1,984,800 Shares outstanding reference: 42,644,388 shares +1 more

4 metrics

Shares to be sold 20,000 shares Class A shares covered by the Rule 144 notice

Aggregate market value $1,984,800 Value for 20,000 Class A shares listed in the securities information

Shares outstanding reference 42,644,388 shares Reference outstanding Class A shares in the securities information

Proposed sale date September 8, 2026 Date listed for the proposed sale and option exercise

Key Terms

Rule 144, Stock Option Exercise, attorney-in-fact, Class A

4 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Stock Option Exercise financial

"Class A | 09/08/2026 | Stock Option Exercise | Issuer"

A stock option exercise is the act of using a previously granted right to buy shares of a company's stock at a specific, predetermined price by paying that price and receiving the shares. It matters to investors because exercising changes who owns the shares (which can dilute existing ownership), can trigger taxable events and shift potential gains or losses, and affects voting power and the company’s outstanding share count—like turning a voucher into an actual product that becomes part of circulating supply.

attorney-in-fact regulatory

"as attorney-in-fact for Thomas P. Lynch"

An attorney-in-fact is the person or entity given legal authority through a power of attorney to act on behalf of another for specific tasks, such as signing documents, voting shares, or handling transactions. For investors, this matters because it lets a trusted representative make timely decisions or complete paperwork when the owner cannot, much like handing keys to someone to run errands on your behalf—so checks on scope and limits of that authority are important.

Class A financial

"Class A | Fidelity Brokerage Services LLC 900 Salem Street"

Class A denotes a specific group of a company’s shares that carry a particular set of rights—most commonly different voting power or dividend priority compared with other share classes. Think of it like different seats on a bus where some seats let you steer and others only ride: knowing whether a share is Class A tells investors how much influence they have over company decisions and how returns might be distributed, which affects control and value.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What does the Form 144 filing for BLLN disclose?

It discloses that officer Thomas P. Lynch has filed a notice under Rule 144 to sell 20,000 Class A shares of BillionToOne, Inc. The filing provides the proposed sale details, including share amount, valuation, and timing.

How many BillionToOne (BLLN) shares are covered by this Rule 144 notice?

The notice covers a proposed sale of 20,000 Class A shares of BillionToOne, Inc. These shares are expected to be sold in connection with a stock option exercise reported in the same filing.

What is the indicated market value of the BLLN shares in this Form 144?

The filing lists an aggregate market value of $1,984,800 for the 20,000 Class A shares of BillionToOne, Inc. covered by the notice, based on the price information provided in the securities information section.

When are the BLLN shares expected to be sold under this Form 144?

The Form 144 lists a proposed sale date of September 8, 2026 for the 20,000 Class A shares of BillionToOne, Inc., with sales expected to occur on NASDAQ through Fidelity Brokerage Services LLC.

What transaction triggers the sale of BLLN shares in this filing?

The sale is associated with a Stock Option Exercise, with the issuer listed as the party for the exercise and cash as the form of payment, followed by the proposed sale of 20,000 Class A shares.

Who is executing the sale of BillionToOne (BLLN) shares in this notice?

The shares are to be sold through Fidelity Brokerage Services LLC. The Form 144 is signed by /s/ Wade Moss as a duly authorized representative of Fidelity Brokerage Services LLC, acting as attorney-in-fact for Thomas P. Lynch.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/08/2026 - 01:52 PM Accepted by SEC EDGAR 09/08/2026 - 01:52 PM Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001659824
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	BillionToOne, Inc.
SEC File Number	001-42934
Address of Issuer	1035 O'BRIEN DRIVE MENLO PARK CALIFORNIA 94025
Phone	650-460-2551
Name of Person for Whose Account the Securities are To Be Sold	Lynch Thomas P.
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Class A	Fidelity Brokerage Services LLC 900 Salem Street Smithfield RI 02917	20000	1984800.00	42644388	09/08/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Class A	09/08/2026	Stock Option Exercise	Issuer			20000	09/08/2026	Cash

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Nothing to Report

144: Remarks and Signature

Remarks
Date of Notice	09/08/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	06/08/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/Wade Moss, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Thomas P. Lynch
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)