SEC Form 4 · accession 0002087127-26-000011
BillionToOne, Inc. · BLLN
Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗
Reporting owner
David Tsao
Officer — Chief Technology Officer · Director
Period of report
Sep 9, 2026
Accepted (ET)
Sep 11, 2026 · 6:01 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 9, 2026 | M | 10,000 | $2.80 | A | 11,000 | D | |
| Class A Common Stock | Sep 9, 2026 | M | 10,000 | $2.80 | A | 21,000 | D | |
| Class A Common Stock | Sep 9, 2026 | S | 10,000 | $97.54 | D | 11,000 | D | |
| Class A Common Stock | Sep 9, 2026 | S | 10,000 | $100.00 | D | 1,000 | 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)F2 | $2.80 | Sep 9, 2026 | M | 10,000 | D | — | Jun 7, 2031 | Class A Common Stock | 10,000 | 570,000 | D |
| Stock Option (right to buy)F2 | $2.80 | Sep 9, 2026 | M | 10,000 | D | — | Jun 7, 2031 | Class A Common Stock | 10,000 | 560,000 | 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 5, 2026.
- F2The options are fully vested and exercisable.