Company: BLLN
Filing Date: 2025-09-17
Form Type: DRS/A
Source: 0001193125-25-206347
Chunk: 131

Company: BillionToOne, Inc.
Filing Date: 2025-09-17
Form: DRS/A
Chunk 131
---
2025, and excludes:

| • |     | up to 9,660 shares of our Class A common stock issuable upon the exercise of the 
 A-6 Warrant for an exercise price of $2.5879 per share;                          |

| • |     | up to 80,357 shares of our Class A common stock issuable upon the exercise of the 2021 Common Warrant for an exercise 
 price of $2.80 per share;                                                                                             |

| • |     | up to 41,209 shares of our Class A common stock issuable upon the exercise of the 2022 Common Warrant for an exercise 
 price of $10.92 per share;                                                                                            |

| • |     | shares of our Class A common stock reserved for future issuance under our 2025 Plan, which                                                                                                                                                           
 will become effective upon the effectiveness of the registration statement of which this prospectus forms a part, as well as any future increases in the number of shares of our Class A common stock reserved for issuance under the 2025 Plan; and |

| • |     | shares of our Class A common stock reserved for future issuance under                                                                                                                                                                             
 the ESPP, which will become effective upon the effectiveness of the registration statement of which this prospectus forms a part, as well as any future increases in the number of shares of our Class A common stock reserved for issuance under 
 the ESPP.                                                                                                                                                                                                                                         |

83

Dilution If you invest in our Class A common stock in this offering, your ownership interest will be diluted to the extent of the difference between the initial public offering price per share of our Class A common stock and the pro forma as adjusted net tangible book value per share of our Class A common stock immediately after this offering. Our historical net tangible book value (deficit) as of June 30, 2025 was ($249 million), or ($22.46) per share. Our historical net tangible book value (deficit) per share represents our total tangible assets less our total liabilities and redeemable convertible preferred stock (which is not included within stockholders’ (deficit) equity), divided by the number of shares of common stock outstanding as of June 30, 2025. Our pro forma net tangible book value as of June 30, 2025, was $ million, or $ per share. Our pro forma net tangible book value per share represents our total tangible assets less our total liabilities, divided by the number of shares of Class A and Class B