Form 4 Filing for BillionToOne, Inc. - Insider Transactions

This filing details several transactions by Thomas P. Lynch, General Counsel, Chief Compliance Officer and Secretary of BillionToOne, Inc. On September 8, 2026, Mr. Lynch engaged in multiple transactions involving Class A Common Stock. He acquired shares through the exercise of stock options at prices ranging from $8.65 to $30.78. Concurrently, he disposed of a significant number of shares. These sales were executed under a Rule 10b5-1 trading plan, with sale prices reported as weighted averages due to multiple transactions occurring at prices ranging from $96.47 to $101.41 per share. The filing also includes details on the reporting person's ownership of derivative securities, specifically stock options, with various expiration dates and exercise prices.