Company: BLLN
Filing Date: 2025-10-07
Form Type: S-1
Source: 0001193125-25-233697
Chunk: 308

Company: BillionToOne, Inc.
Filing Date: 2025-10-07
Form: S-1
Chunk 308
---
 income tax purposes) created or organized in the 
 United States or under the laws of the United States, any state thereof or the District of Columbia;                      |

| • |     | an estate, the income of which is includable in gross income for U.S. federal income tax purposes regardless of its source; 
 or                                                                                                                          |

| • |     | a trust if (1) a court within the United States is able to exercise primary supervision over the administration of the                                                                                                                  
 trust and one or more “U.S. persons,” as defined under the Code (as defined below), have the authority to control all substantial decisions of the trust or (2) such trust has made a valid election to be treated as a U.S. person for 
 U.S. federal income tax purposes.                                                                                                                                                                                                       |

This discussion is based on current provisions of the Internal Revenue Code of 1986, as amended (the Code), existing, temporary and proposed U.S. treasury regulations promulgated thereunder (Treasury Regulations), judicial opinions, published positions of the Internal Revenue Service (the IRS), and other applicable authorities, all of which are subject to change or to differing interpretation, possibly with retroactive effect. Any change could alter the tax consequences to non-U.S.holders described in this prospectus. This discussion assumes that a non-U.S.holder holds shares of our Class A common stock as a capital asset (generally, property held for investment) for U.S. federal income tax purposes. This discussion does not address all aspects of U.S. federal income taxation that may be important to a particular non-U.S.holder in light of that non-U.S.holder’s individual circumstances, nor does it address any aspects of the unearned income Medicare contribution tax pursuant to the Health Care and Education Reconciliation Act of 2010, any U.S. federal tax consequences (such as gift or estate taxes) other than income taxes, any U.S. alternative minimum taxes, the impact of special tax accounting rules under Section 451(b) of the Internal Revenue Code of 1986, as amended (the Code), or any state, local or non-U.S.taxes. This discussion may not apply, in whole or in part, to particular non-U.S.holders in light of their individual circumstances or to holders subject to special treatment under the U.S. federal income tax laws (such as taxpayers that have elected mark-to-marketaccounting, insurance companies, tax-exemptorganizations, government organizations, tax-qualifiedretirement plans,