Oguzhan Atay, an officer and director of BillionToOne, Inc., filed a Form 144 notice on November 2, 2026, proposing to sell 25,001 Class A shares acquired through a stock option exercise on the same date.

Key Highlights

  • Proposed sale: 25,001 Class A shares with an aggregate market value of $2,829,363.17, according to the filing.
  • Acquisition method: The shares were acquired via stock option exercise from the issuer on November 2, 2026, with cash payment.
  • Shares outstanding: The filing lists 42,644,388 Class A shares outstanding at the time of the notice.
  • Trading plan: The filing indicates reliance on Rule 10b5-1, with a plan adoption date of June 5, 2026.
  • Broker named: Fidelity Brokerage Services LLC, 900 Salem Street, Smithfield, RI 02917, is listed as the broker for the proposed sale on NASDAQ.
  • Aggregated sellers: The filing discloses prior three-month sales by Oguzhan Atay, his spouse Ezgi N. Akcinar Atay, and the Atay 2021 Dynasty Trust, as required by Rule 144 aggregation rules.

Oguzhan Atay's Proposed Rule 144 Sale and Prior Three-Month Activity at BillionToOne

According to the Form 144 filing with the SEC, Oguzhan Atay, who is identified as both an officer and a director of BillionToOne, Inc. (NASDAQ:BLLN), filed a notice of proposed sale of 25,001 Class A shares. The filing lists the approximate date of sale as November 2, 2026, and states the aggregate market value of the shares to be sold as $2,829,363.17. The shares were acquired on November 2, 2026, through a stock option exercise from the issuer, with cash as the nature of payment.

The filing discloses that Atay is relying on Rule 10b5-1, citing a plan adoption date of June 5, 2026. Under the filing's remarks section, it notes that sales within the past three months also occurred in the account of Ezgi N. Akcinar Atay, described as the spouse of Oguzhan Atay, and in the Atay 2021 Dynasty Trust, "which were made by Icontrust Llc, trustee on the account," with Oguzhan Atay identified as "an account stakeholder in the Atay 2021 Dynasty Trust." These are disclosed because Rule 144 requires aggregation of sales by certain related persons.

The three-month sales history listed in the filing covers multiple transactions. Oguzhan Atay's disclosed sales during that period include dates of August 3, August 5, September 14, September 28, October 12, October 14, October 15, and October 28, 2026, with amounts ranging from 3,183 to 32,500 shares per transaction. Ezgi N. Akcinar Atay's disclosed sales occurred on August 3, September 14, September 28, October 12, October 14, and October 28, 2026. The Atay 2021 Dynasty Trust recorded one disclosed sale of 2,500 shares on August 3, 2026, with gross proceeds of $343,425.00.

What Was Disclosed

BillionToOne officer and director Oguzhan Atay filed a Form 144 on November 2, 2026, proposing to sell 25,001 Class A shares obtained via stock option exercise. The filing also details aggregated prior sales by Atay, his spouse, and a related trust over the preceding three months.