Company: BLLN
Filing Date: 2025-09-17
Form Type: DRS/A
Source: 0001193125-25-206347
Chunk: 277

Company: BillionToOne, Inc.
Filing Date: 2025-09-17
Form: DRS/A
Chunk 277
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 promissory note, with the recourse, interest, security and redemption provisions determined by the 
 administrator to the extent permitted under and in accordance with applicable law;                               |

| • |     | Cancellation of indebtedness; |

| • |     | Surrender of shares of common stock that the optionee already owns; or |

| • |     | If our shares of common stock are publicly traded, through a sale of shares subject to the option through a securities 
 broker; or Other methods permitted under applicable laws.                                                              |

Options vest as determined by the administrator. In general, we have granted options that vest over a four-year period. Options expire at the time determined by the administrator, but in no event more than ten years after they are granted, and generally expire earlier if the optionee’s service terminates. Restricted shares Restricted shares may be awarded or sold under the 2018 Plan in return for cash or cash equivalents or, as permitted by the administrator in its sole discretion, in exchange for services rendered to us, or through any other means permitted by applicable law. Restricted shares vest as determined by the administrator. The plan administrator determines the terms and conditions of restricted shares, including vesting and forfeiture terms. If a participant’s service relationship with us ceases for any reason, we may receive any or all of the shares of common stock held by the participant that have not vested as of the date the participant terminates service with us through a forfeiture condition or a repurchase right. Corporate transactions In the event that we are a party to a merger, consolidation or the capital reorganization or business combination transaction, including any transaction or series of transaction in which any person becomes the beneficial owner of more than 50% of our then outstanding capital stock, or in the event of a sale of all or substantially all of our assets, awards granted under the 2018 Plan will be treated in the manner determined by the administrator. Such treatment may include, without limitation, one or more of the following with respect to outstanding awards:

| • |     | The continuation, assumption or substitution of an award by the surviving entity or its parent; |

| • |     | Cancellation of the award in exchange for a payment equal to the excess, if any, of the value of the shares subject to the 
 award over any exercise price per share applicable to the award; or                                                        |

| • |     | Cancellation of the award without payment of any consideration. |

The administrator is not obligated to treat all awards in the same manner. Changes in capital