Form 4 Filing for BillionToOne, Inc. - Officer Stock Sale

Nancy JoAnn Johnson, Senior Vice President of Sales and Commercial Operations at BillionToOne, Inc., reported a sale of 801 shares of Class A Common Stock on July 1, 2026. The sale was executed as part of a Rule 10b5-1 trading plan adopted on March 6, 2026. The shares were sold at a weighted average price of $124.9137, with individual transactions ranging from $124.900 to $124.940. Following the transaction, Johnson holds 21,099 shares of Class A Common Stock. This filing is a standard disclosure of insider trading activity.