Company: BLLN
Filing Date: 2025-10-07
Form Type: S-1
Source: 0001193125-25-233697
Chunk: 3

Company: BillionToOne, Inc.
Filing Date: 2025-10-07
Form: S-1
Chunk 3
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 of the shares of Class A common stock being offered by this prospectus for sale, at the initial public offering price, to our officers, directors and employees through a directed share program. See the section titled “Underwriting – Directed share program.” We have granted the underwriters an option for a period of 30 days to purchase up to additional shares of Class A common stock. Investing in our Class A common stock involves a high degree of risk. See “ Risk factors” beginning on page 22. Neither the Securities and Exchange Commission nor any other state securities commission has approved or disapproved of these securities or passed on the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense. The underwriters expect to deliver the shares to purchasers on or about , 2025.

| J.P. Morgan |     | Piper Sandler          |     | Jefferies |     | William Blair |
| Stifel      |     | Wells Fargo Securities |     |           |     | BTIG          |

, 2025

BILLION TOONE We strive to remove the fear of the unknown. Our revolutionary technology allows us to push beyond the current limitations in diagnostics so we can detect disease one molecule at a time. We provide patients with powerful and precise information about the state of their health for themselves and their children. And it's only the beginning of what we seek to do.

Key Metrics $265M+ annualized revenue run-rate (ARR)1 84% YOY revenue growth2 Emerging profitability3 $100B US annual market opportunity4 REVENUE $209M LTM revenue5 167% CAGR (2021-2024) TESTS ACCESSIONED6 508K LTM tests accessioned as of June 30, 2025 51% YOY tests accessioned growth2 1M+ tests accessioned since launch GROSS PROFIT MARGIN OTHER 65% gross profit margin 2025 14 pp YOY increase in gross profit margin2 $1.8M ARR per sales representative 225M+ covered lives7 1. Q2 2025 revenue of $66.6M annualized. Calculated as Q2 2025 revenue multiplied by 4. 2. Q2 2025 compared to Q2 2024, 3. Based on $.01 EBITDA in Q2 2025 and ($0.2M) net loss in Q2 2025. See Management’s