BillionToOne (BLLN) GC Thomas P. Lynch Exercises Options, Sells Shares

What Happened
Thomas P. Lynch — General Counsel, Chief Compliance Officer and Secretary of BillionToOne (BLLN) — exercised a total of 35,112 option shares on 2026-09-17 at multiple strike prices (19,384 @ $8.65; 6,968 @ $11.55; 2,920 @ $17.12; 5,840 @ $30.78) for an aggregate exercise cost of approximately $477,897. The same day he sold those 35,112 shares in the open market for weighted-average prices around $110.30–$110.36, generating gross proceeds of about $3.87 million. The pattern is consistent with a cashless exercise (exercise followed by immediate sale).

Key Details

• Transaction date: 2026-09-17; Form 4 filed: 2026-09-21 (filed four days after the trades; Form 4s are normally due within two business days).
• Options exercised: 35,112 total (19,384; 6,968; 2,920; 5,840) at strikes of $8.65, $11.55, $17.12 and $30.78 — total exercise cash paid ≈ $477,897.
• Shares sold: same 35,112 shares in multiple open-market trades; reported weighted-average prices and proceeds by tranche:
  • 19,384 shares — $110.36 avg — $2,139,193 (sales ranged $110.00–$110.97)
  • 6,968 shares — $110.30 avg — $768,561 (sales ranged $110.00–$110.89)
  • 2,920 shares — $110.31 avg — $322,100
  • 5,840 shares — $110.29 avg — $644,112
  • Combined gross proceeds ≈ $3,873,966.
• Notable footnotes: trades were made under a Rule 10b5-1 trading plan adopted June 8, 2026 (F1); sale prices are weighted averages reported with ranges (F2, F3); the options were fully vested and exercisable (F4).
• Shares owned after transaction: not specified in the excerpt of the filing provided.

Context

• This was an option exercise immediately followed by sales — a common way insiders monetize vested options (cashless exercise). The presence of a 10b5-1 plan indicates the sales were pre-arranged.
• These transactions are routine monetization rather than an outright open-market purchase (purchases are generally viewed as stronger bullish signals). This summary is factual and does not infer motive.