A Form 144 notice of proposed sale was filed on November 2, 2026, on behalf of Atay Oguzhan, identified as a member of the immediate family of an officer and director of BillionToOne, Inc. (NASDAQ:BLLN), disclosing a plan to sell 5,334 Class A shares through Fidelity Brokerage Services LLC.

Key Highlights

  • Proposed sale: 5,334 Class A shares of BillionToOne, Inc. with an aggregate market value of $603,648.78, with an approximate sale date of 11/02/2026.
  • Total Class A shares outstanding: 42,644,388, according to the filing.
  • Acquisition of shares to be sold: The 5,334 shares were acquired on 05/01/2024 as pre-IPO shares from the issuer, with payment made in cash on 05/01/2024.
  • Rule 10b5-1 plan: The filing indicates a trading plan adoption date of 06/07/2026.
  • Broker: Fidelity Brokerage Services LLC, 900 Salem Street, Smithfield, RI 02917.
  • Related-party sales disclosed: Oguzhan Atay (Officer and Director), his spouse Ezgi N. Akcinar Atay, and the Atay 2021 Dynasty Trust reported multiple Class A share sales in the prior three months, totaling tens of thousands of shares across numerous transactions.

BillionToOne Family-Affiliated Form 144 Filing: Proposed Sale Details and Prior Three-Month Sales

According to the filing, the person for whose account the securities are to be sold is identified as Atay Oguzhan, whose relationship to BillionToOne, Inc. is listed as "Member of immediate family of any of the foregoing." The remarks section of the filing states that "Today's sale and sales within the past 3 months occurred in the account of Ezgi N. Akcinar Atay, who is the spouse of Oguzhan Atay, an Officer and Director of the company." The filing also notes that "There are also sales within the past 3 months which occurred in the Atay 2021 Dynasty Trust which were made by Icontrust Llc, trustee on the account" and that "Oguzhan Atay is an account stakeholder in the Atay 2021 Dynasty Trust."

The filing discloses a series of prior three-month Class A share sales aggregated across these related accounts. Oguzhan Atay's reported sales include transactions on 08/03/2026 (32,500 shares, gross proceeds $4,450,834.75), 08/05/2026 (15,539 shares, $2,331,351.91), 09/14/2026 (24,999 shares, $2,507,908.84), 09/28/2026 (8,333 shares, $1,005,293.12), 10/12/2026 (16,667 shares, $1,563,124.60), 10/14/2026 (3,183 shares, $313,019.72), 10/15/2026 (5,150 shares, $516,188.62), and 10/28/2026 (8,333 shares, $983,294.00). Ezgi N. Akcinar Atay reported sales on 08/03/2026 (12,500 shares, $1,717,125.00), 09/14/2026 (5,332 shares, $522,536.00), 09/28/2026 (2,666 shares, $321,626.24), 10/12/2026 (2,667 shares, $260,325.87), 10/14/2026 (2,667 shares, $261,366.00), and 10/28/2026 (2,667 shares, $314,706.00). The Atay 2021 Dynasty Trust reported a sale on 08/03/2026 (2,500 shares, $343,425.00).

The notice was signed by Jennifer Ruchti, described as "a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Oguzhan Atay," and dated 11/02/2026. The filing indicates reliance on a Rule 10b5-1 plan adopted on 06/07/2026.

What Was Disclosed

A Form 144 was filed on 11/02/2026 for a proposed sale of 5,334 Class A shares of BillionToOne, Inc. (NASDAQ:BLLN) with an aggregate market value of $603,648.78, alongside a disclosure of related-party sales made over the prior three months by Oguzhan Atay, his spouse, and the Atay 2021 Dynasty Trust.