Form 4 Filing for BillionToOne, Inc.

This filing details a transaction by Kolluri Krishna Kittu, a director and ten percent owner of BillionToOne, Inc. On June 10, 2026, Mr. Kittu acquired 3017 shares of Class A Common Stock through the grant of restricted stock units (RSUs). These RSUs are subject to a service-based vesting requirement, which will be satisfied on the earlier of the next annual meeting of stockholders or the one-year anniversary of June 10, 2026. Following this transaction, Mr. Kittu owns 11350 shares of Class A Common Stock. The transaction code is 'A' for acquisition, and the price per share is reported as 0.0, consistent with the RSU grant. The filing was signed on June 11, 2026.