Form 4: BillionToOne CTO Executes Stock Option Exercise and Sale

Chief Technology Officer David Tsao exercised 20,000 stock options and sold a portion of the resulting shares under a Rule 10b5-1 plan.

Summary

• David Tsao, Chief Technology Officer of BillionToOne, Inc., exercised 20,000 stock options at an exercise price of $2.80 per share.
• Following the exercise, the reporting person sold a total of 20,000 shares of Class A Common Stock.
• The sales were executed in multiple tranches at weighted average prices ranging from approximately $98.74 to $104.47 per share.
• The transactions were conducted pursuant to a pre-established Rule 10b5-1 trading plan adopted on March 6, 2026.

Sentiment

Score: 5

Explanation: StockSavvy.ai views this as a neutral event, as the transactions were executed under a pre-planned 10b5-1 arrangement, which is standard practice for executive liquidity.

Positives

• The executive maintains a significant remaining equity stake of 1,000 shares post-transaction, in addition to 1,250,000 unexercised options.
• The transactions were executed under a pre-planned Rule 10b5-1 program, which is a standard mechanism for insiders to sell stock without triggering concerns regarding non-public information.

Negatives

• The transaction represents a liquidation of equity by a key member of the executive leadership team.

Risks

• Insider selling can sometimes be perceived negatively by the market, potentially impacting short-term investor sentiment.

Future Outlook

No specific forward-looking guidance regarding company operations was provided in this filing.

Industry Context

StockSavvy.ai notes that insider selling via 10b5-1 plans is a routine practice for executives to diversify their personal portfolios and is generally viewed as a neutral event by institutional investors when conducted according to a pre-set schedule.

Comparison to Industry Standards

• The use of Rule 10b5-1 plans is the industry standard for corporate insiders to manage equity holdings while maintaining compliance with SEC regulations.
• The scale of the sale relative to the executive's total holdings is consistent with typical executive compensation and liquidity management strategies.

Stakeholder Impact

• Shareholders should note the reduction in the CTO's direct holdings, though the transaction was pre-planned.

Next Steps

• No future actions or milestones were disclosed in this filing.

Key Dates

Keywords

BillionToOne, BLLN, Insider Trading, Form 4, Stock Options, Executive Compensation, Rule 10b5-1