Sakakibara Shan Riku 4

What Happened Sakakibara Shan Riku, Chief Product Officer of BillionToOne, exercised option-related derivatives and sold shares on June 24, 2026. The filing shows two option-related transactions of 4,000 shares each at an exercise price of $8.65 per share (reported amounts $34,600 each). Separately, Sakakibara sold two blocks of 4,000 shares in open-market transactions at $110.00 per share, generating gross proceeds of $440,000 each (total $880,000). The transactions were reported on a Form 4 filed June 26, 2026.

Key Details

• Transaction date: 2026-06-24 (reported 2026-06-26 — timely filing).
• Option exercise entries: 4,000 shares @ $8.65 (acquired) = $34,600; 4,000 shares @ $8.65 (derivative disposition) = $34,600.
• Open-market sales: 4,000 shares @ $110.00 = $440,000 (two separate sales; total $880,000).
• Footnotes: Transactions were executed under a Rule 10b5-1 trading plan adopted March 6, 2026 (F1). Options are fully vested and exercisable; underlying grant details referenced in the Form 3 filed Nov 5, 2025 (F2).
• Shares owned after the transactions: not specified in the provided summary — see the full Form 4 for post-transaction holdings.

Context

• Code M entries denote option exercises. The combination of exercise entries and same-day open-market sales indicates the exercised shares were sold the same day (a common cashless or immediate-sale pattern), but the filing should be consulted for exact mechanics.
• The trades were executed under a pre-established 10b5-1 plan, which often governs scheduled insider sales and reduces the implication that sales reflect a change in sentiment. The reporting person is an officer (CPO); this is not presented as a 10% owner transaction.