BillionToOne CEO Atay Oguzhan Sells Shares, Exercises Options

What Happened
Atay Oguzhan, BillionToOne (BLLN) Chairman & CEO, exercised 24,999 vested options (16,666 + 8,333) at an exercise price of $2.80 (cost ≈ $70k) and sold a total of 55,330 shares on September 14, 2026. The open‑market sales (multiple trades) generated about $3.10 million in gross proceeds. The exercise (derivative) transactions are coded M and the sales are coded S on the Form 4.

Key Details

• Transaction date: September 14, 2026; Form 4 filed September 16, 2026 (appears timely).
• Options exercised: 16,666 and 8,333 shares at $2.80 each (fully vested per footnote F12). Acquisition cost ≈ $69,997.
• Shares sold: 55,330 total (30,331 open‑market share sales + 24,999 shares from the exercised options sold). Gross proceeds ≈ $3,100,440.
• Sale prices: weighted‑average prices reported for lots; individual ranges shown in footnotes F2–F9 (roughly $98.06–$101.82 per share across the sales).
• Plans and holdings: Trades were effected under Rule 10b5‑1 trading plans (reporting person’s plan adopted June 5, 2026 — F1; spouse’s plan adopted June 7, 2026 — F10). Footnote F11 indicates some shares are held by the reporting person’s spouse.
• Shares owned after transaction: not specified in the excerpt provided; see the filed Form 4 for post‑transaction holdings.

Context
These transactions combined an option exercise and subsequent sales (common when insiders exercise options and immediately sell either to cover exercise/tax costs or as planned liquidity). The options were fully vested, and multiple sales were executed at market prices under pre‑scheduled 10b5‑1 plans — a procedural detail that can reduce the appearance of selective timing but does not indicate the insider’s private view of the company.