SEC Form 4 · accession 0002070849-26-000069
BillionToOne, Inc. · BLLN
Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗
Reporting owner
Thomas P. Lynch
Officer — See Remarks
Period of report
Sep 17, 2026
Accepted (ET)
Sep 21, 2026 · 7:00 pm EDT
Rule 10b5-1 plan
yes — trade under a plan
Issuer CIK
0002070849
Table I — non-derivative securities
| Security | Date | Code | Shares | Price | A/D | Owned after | D/I | Nature of ownership |
|---|---|---|---|---|---|---|---|---|
| Class A Common Stock | Sep 17, 2026 | M | 19,384 | $8.65 | A | 20,084 | D | |
| Class A Common Stock | Sep 17, 2026 | M | 6,968 | $11.55 | A | 27,052 | D | |
| Class A Common Stock | Sep 17, 2026 | M | 2,920 | $17.12 | A | 29,972 | D | |
| Class A Common Stock | Sep 17, 2026 | M | 5,840 | $30.78 | A | 35,812 | D | |
| Class A Common StockF2 | Sep 17, 2026 | S | 19,384 | $110.3587 | D | 16,428 | D | |
| Class A Common StockF3 | Sep 17, 2026 | S | 6,968 | $110.2986 | D | 9,460 | D | |
| Class A Common StockF3 | Sep 17, 2026 | S | 2,920 | $110.3083 | D | 6,540 | D | |
| Class A Common StockF2 | Sep 17, 2026 | S | 5,840 | $110.2931 | D | 700 | D |
Table II — derivative securities
| Security | Conv. / exercise price | Date | Code | Shares | A/D | Exercisable | Expires | Underlying | Underlying shares | Owned after | D/I |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Stock Option (right to buy)F4 | $8.65 | Sep 17, 2026 | M | 19,384 | D | — | Jan 18, 2033 | Class A Common Stock | 19,384 | 48,974 | D |
| Stock Option (right to buy)F4 | $11.55 | Sep 17, 2026 | M | 6,968 | D | — | Oct 17, 2033 | Class A Common Stock | 6,968 | 4,063 | D |
| Stock Option (right to buy)F4 | $17.12 | Sep 17, 2026 | M | 2,920 | D | — | Oct 16, 2034 | Class A Common Stock | 2,920 | 5,417 | D |
| Stock Option (right to buy)F4 | $30.78 | Sep 17, 2026 | M | 5,840 | D | — | Sep 30, 2035 | Class A Common Stock | 5,840 | 30,834 | D |
Explanation of responses
- F1The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on June 8, 2026.
- F2The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $110.000 to $110.970 per share, inclusive. The holder undertakes to provide, upon written request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
- F3The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $110.000 to $110.890 per share, inclusive. The holder undertakes to provide, upon written request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
- F4The options are fully vested and exercisable. The terms of the underlying option grant are as previously reported on the Reporting Person's Form 3 filed on November 5, 2025.
Remarks
General Counsel, Chief Compliance Officer and Secretary