SEC Form 4 · accession 0002088549-26-000010
BillionToOne, Inc. · BLLN
Statement of changes in beneficial ownership, as filed. Original on EDGAR ↗
Reporting owner
Oguzhan Atay
Officer — Chairman and CEO · Director
Period of report
Sep 14, 2026
Accepted (ET)
Sep 16, 2026 · 6:43 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 14, 2026 | M | 16,666 | $2.80 | A | 16,666 | D | |
| Class A Common Stock | Sep 14, 2026 | M | 8,333 | $2.80 | A | 24,999 | D | |
| Class A Common StockF2 | Sep 14, 2026 | S | 4,465 | $98.6314 | D | 20,534 | D | |
| Class A Common StockF3 | Sep 14, 2026 | S | 2,456 | $99.5713 | D | 18,078 | D | |
| Class A Common StockF4 | Sep 14, 2026 | S | 2,531 | $100.5809 | D | 15,547 | D | |
| Class A Common StockF5 | Sep 14, 2026 | S | 7,214 | $101.4407 | D | 8,333 | D | |
| Class A Common StockF6 | Sep 14, 2026 | S | 1,680 | $98.6358 | D | 6,653 | D | |
| Class A Common StockF7 | Sep 14, 2026 | S | 1,500 | $99.5683 | D | 5,153 | D | |
| Class A Common StockF8 | Sep 14, 2026 | S | 2,010 | $100.7756 | D | 3,143 | D | |
| Class A Common StockF9 | Sep 14, 2026 | S | 3,143 | $101.4919 | D | 0 | D | |
| Class A Common StockF11 | Sep 14, 2026 | S | 2,666 | $98.00 | D | 159,834 | I | By spouse |
| Class A Common StockF11 | Sep 14, 2026 | S | 2,666 | $98.00 | D | 157,168 | I | By spouse |
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)F12 | $2.80 | Sep 14, 2026 | M | 16,666 | D | — | Jun 7, 2031 | Class A Common Stock | 16,666 | 510,295 | D |
| Stock Option (right to buy)F12 | $2.80 | Sep 14, 2026 | M | 8,333 | D | — | Jun 7, 2031 | Class A Common Stock | 8,333 | 501,962 | 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.
- F10The transactions reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person's spouse on June 7, 2026.
- F11Represents shares held by the Reporting Person's spouse.
- F12The options are fully vested and exercisable.
- F2The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $98.060 to $99.055 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 $99.060 to $100.055 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 reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $100.060 to $101.040 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.
- F5The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $101.085 to $101.805 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.
- F6The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $98.140 to $99.010 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.
- F7The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $99.160 to $100.130 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.
- F8The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $100.230 to $101.200 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.
- F9The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $101.250 to $101.820 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.