Company: BLLN
Filing Date: 2025-10-17
Form Type: S-1/A
Source: 0001193125-25-242632
Chunk: 280

Company: BillionToOne, Inc.
Filing Date: 2025-10-17
Form: S-1/A
Chunk 280
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 pay the exercise or purchase price of an award or to satisfy tax withholding obligations related to any award. Administration The compensation committee of our Board of Directors will administer our 2025 Plan. The compensation committee will have complete discretion to make all decisions relating to our 2025 Plan and outstanding awards, including repricing outstanding options and modifying outstanding awards in other ways. Eligibility Employees, non-employeedirectors, consultants and advisors will be eligible to participate in our 2025 Plan. Under our 2025 Plan, the aggregate grant date fair value of awards granted to our non-employee directors may not exceed $750,000 in any one fiscal year, provided, however, that such limitation that will not apply in the fiscal year in which a non-employee director is initially appointed to our Board of Directors or with respect to the non-executive chair of our Board of Directors. Types of awards Our 2025 Plan provides for the following types of awards:

| • |     | incentive and nonstatutory stock options; |

| • |     | stock appreciation rights; |

| • |     | restricted shares; and |

| • |     | restricted stock units. |

Options and stock appreciation rights The exercise price for options granted under our 2025 Plan may not be less than 100% of the fair market value of our Class A common stock on the grant date. Optionees will be permitted to pay the exercise price in cash or, with the consent of the compensation committee:

| • |     | with shares of Class A common stock that the optionee already owns; |

| • |     | by an immediate sale of shares through a broker approved by us; |

| • |     | by instructing us to withhold a number of shares having an aggregate fair market value that does not exceed the exercise 
 price; or                                                                                                                |

| • |     | by other methods permitted by applicable law. |

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An optionee who exercises a stock appreciation right receives the increase in value of our Class A common stock over the base price. The base price for stock appreciation rights may not be less than 100% of the fair market value of our Class A common stock on the grant date. The settlement value of a stock appreciation right may be paid in cash, shares of our common stock or a combination. Options and stock appreciation rights vest as determined by the compensation committee. In general, they will vest over a four-year period following the date of grant. Options and stock appreciation rights expire at the time determined by the compensation