Sakakibara Shan Riku 4

What Happened
Sakakibara Shan Riku, Chief Product Officer of BillionToOne (BLLN), exercised stock options to acquire 4,000 shares on July 9, 2026 and sold a total of 8,000 shares in open-market transactions the same day. Option exercises: 174 shares at $8.65 (cost $1,505) and 3,826 shares at $30.78 (1,117 / 1,355 / 1,354 lots; combined cost $117,764), for a total exercise cost of $119,269. Open-market sales: 8,000 shares sold at $125.00 each, generating $1,000,000 in gross proceeds. The filings also show the exercised derivative positions were disposed, indicating the exercised shares were promptly sold.

Key Details

• Transaction date: July 9, 2026 (reported on Form 4 filed July 13, 2026).
• Exercise details: 174 @ $8.65 ($1,505); 1,117 @ $30.78 ($34,381); 1,355 @ $30.78 ($41,707); 1,354 @ $30.78 ($41,676). Total exercised = 4,000 shares; total exercise cost = $119,269.
• Sales details: Open-market sales totaling 8,000 shares at $125.00 each = $1,000,000 gross proceeds.
• Net proceeds (approx.): $1,000,000 − $119,269 = $880,731 before taxes, broker fees and any withholdings.
• Shares owned after transaction: Not specified in the provided data.
• Footnotes: Transactions were made pursuant to a Rule 10b5-1 trading plan adopted March 6, 2026 (F1). Options were fully vested and exercisable per prior Form 3 (F2).
• Timeliness: Form 4 was filed July 13 for July 9 transactions; Form 4s are generally due within two business days, so this filing appears to have been submitted several days after the transactions.

Context

• These filings show an option exercise followed by immediate sales (often called a cashless exercise or same-day sale), a common way for insiders to cover option strike costs and tax obligations.
• Because the trades were executed under a pre-arranged 10b5-1 plan, they were likely scheduled in advance; such plans limit the ability to infer the insider’s short-term view.
• Sales by insiders are common and do not by themselves indicate company performance; purchases are often more informative for bullish signals.