Shareholders file to sell 15,539 BLLN shares

Affiliated shareholders of BLLN filed a Form 144 to sell up to 15,539 Class A shares through a stock option exercise for cash, with the proposed sale dated 08/05/2026.

Rhea-AI Filing Summary

Affiliated shareholders of BLLN filed a Form 144 to sell up to 15,539 Class A shares through a stock option exercise for cash, with the proposed sale dated 08/05/2026. The filing lists an aggregate market value of $2,331,352.23 for these shares and notes 41,442,834 Class A shares outstanding as of 08/05/2026; this is a baseline figure, not the amount being offered.

Over the prior three months, the filing reports multiple Class A share sales by Oguzhan Atay, Ezgi N. Akcinar Atay, and the Atay 2021 Dynasty Trust on 06/08/2026, 07/06/2026, 07/09/2026, and 08/03/2026, each with specified share amounts and dollar proceeds.

Key Figures

Shares to be sold: 15,539 shares Aggregate market value: $2,331,352.23 Shares outstanding: 41,442,834 shares +3 more

6 metrics

Shares to be sold 15,539 shares Class A shares proposed for sale via stock option exercise on 08/05/2026

Aggregate market value $2,331,352.23 Market value of 15,539 Class A shares proposed to be sold

Shares outstanding 41,442,834 shares Class A shares outstanding as of 08/05/2026

Sale on 06/08/2026 (Oguzhan Atay) 26,250 shares; $2,563,632.00 Class A sale reported for 06/08/2026

Sale on 07/06/2026 (Oguzhan Atay) 26,250 shares; $3,203,733.13 Class A sale reported for 07/06/2026

Sale on 08/03/2026 (Oguzhan Atay) 32,500 shares; $4,450,834.75 Class A sale reported for 08/03/2026

Key Terms

Form 144, Stock Option Exercise, Dynasty Trust

3 terms

Form 144 regulatory

"Affiliated shareholders of BLLN filed a Form 144 to sell up to 15,539"

Form 144 is a document that investors must file with the government when they plan to sell a large number of shares of a company's stock. It helps ensure transparency so everyone knows how many shares are being sold and when, which can impact the stock's price.

Stock Option Exercise financial

"Class A | 08/05/2026 | 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.

Dynasty Trust financial

"Atay 2021 Dynasty Trust 1035 O'Brien Drive Menlo Park CA 94025"

FAQ

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

What does the BLLN Form 144 filed by Atay-related holders disclose?

The Form 144 for BLLN discloses a planned sale of 15,539 Class A shares via stock option exercise for cash on 08/05/2026. It also lists several prior Class A sales by Atay-related holders over the preceding three months.

How many BLLN Class A shares are proposed to be sold under this Form 144?

The filing provides for the potential sale of 15,539 Class A shares of BLLN. These shares are tied to a stock option exercise for cash, with the proposed transaction date shown as 08/05/2026.

What is the aggregate market value of BLLN shares covered by the Form 144?

The Form 144 reports an aggregate market value of $2,331,352.23 for the 15,539 Class A shares proposed to be sold. This figure reflects the market value associated with the planned transaction as disclosed in the filing.

How many BLLN Class A shares were outstanding as of 08/05/2026?

The filing states that 41,442,834 Class A shares of BLLN were outstanding as of 08/05/2026. This number provides a reference for the company’s total Class A share base, separate from the shares proposed for sale.

What recent BLLN share sales by Oguzhan Atay are listed in the Form 144?

The Form 144 lists Oguzhan Atay’s Class A share sales on 06/08/2026, 07/06/2026, 07/09/2026, and 08/03/2026. Each entry includes the specific number of shares sold and the dollar proceeds for those transactions.

Which other BLLN shareholders are mentioned with sales in the past three months?

The filing identifies Ezgi N. Akcinar Atay and the Atay 2021 Dynasty Trust as having sold BLLN Class A shares on 06/08/2026, 07/06/2026, and 08/03/2026, with each sale’s share count and cash amount disclosed.

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

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Available on EDGAR 08/05/2026 - 04:57 PM Accepted by SEC EDGAR 08/05/2026 - 04:56 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	0002088549
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	Atay Oguzhan
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
Relationship to Issuer	Director

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	15539	2331352.23	41442834	08/05/2026	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	08/05/2026	Stock Option Exercise	Issuer			15539	08/05/2026	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

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
Oguzhan Atay 1035 O'Brien Drive Menlo Park CA 94025	Class A	06/08/2026	26250	2563632.00
Ezgi N. Akcinar Atay 1035 O'Brien Drive Menlo Park CA 94025	Class A	06/08/2026	12500	1227812.50
Atay 2021 Dynasty Trust 1035 O'Brien Drive Menlo Park CA 94025	Class A	06/08/2026	2500	245562.50
Oguzhan Atay 1035 O'Brien Drive Menlo Park CA 94025	Class A	07/06/2026	26250	3203733.13
Ezgi N. Akcinar Atay 1035 O'Brien Drive Menlo Park CA 94025	Class A	07/06/2026	12500	1525645.67
Atay 2021 Dynasty Trust 1035 O'Brien Drive Menlo Park CA 94025	Class A	07/06/2026	2500	300000.00
Oguzhan Atay 1035 O'Brien Drive Menlo Park CA 94025	Class A	07/09/2026	12500	1576276.25
Oguzhan Atay 1035 O'Brien Drive Menlo Park CA 94025	Class A	08/03/2026	32500	4450834.75
Ezgi N. Akcinar Atay 1035 O'Brien Drive Menlo Park CA 94025	Class A	08/03/2026	12500	1717125.00
Atay 2021 Dynasty Trust 1035 O'Brien Drive Menlo Park CA 94025	Class A	08/03/2026	2500	343425.00

144: Remarks and Signature

Remarks	There are sales within the past 3 months occurred in the account of Ezgi N. Akcinar Atay, who is the spouse of Oguzhan Atay. Additionally, there are sales within the past 3 months which occurred in the Atay 2021 Dynasty Trust which were made by Icontrust Llc, trustee on the account. Oguzhan Atay is an account stakeholder in the Atay 2021 Dynasty Trust.
Date of Notice	08/05/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	03/06/2026
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/ Joshua Schmitt, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Oguzhan Atay.
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)