Form 4 Filing for BillionToOne, Inc. - Insider Transactions

This filing details significant stock transactions by David Tsao, Chief Technology Officer and Director of BillionToOne, Inc. on October 5, 2026. Tsao acquired 20,000 shares of Class A Common Stock through the exercise of stock options at a price of $2.80 per share. Concurrently, Tsao sold a total of 14,764 shares of Class A Common Stock. These sales were conducted under a Rule 10b5-1 trading plan and occurred at prices ranging from $105.505 to $110.09 per share. The filing indicates that these transactions were executed through a 10b5-1 trading plan, with specific footnotes detailing the weighted average prices and price ranges for the sales. The transactions reflect a mix of option exercises and stock sales by a key executive.