Company: BLLN
Filing Date: 2025-10-17
Form Type: S-1/A
Source: 0001193125-25-242632
Chunk: 186

Company: BillionToOne, Inc.
Filing Date: 2025-10-17
Form: S-1/A
Chunk 186
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 accounting matters, internal controls, and in the preparation of our financial 
 statements;                                                                                                        |

| • |     | engaged a third party to assist in evaluating segregation of duties risks and design and implement controls to address 
 those risks;                                                                                                           |

| • |     | began to design and implement controls related to restricting user and privileged access to appropriate personnel, 
 including as it relates to creating and posting journal entries;                                                   |

| • |     | engaged a third party to assist management in evaluating the accounting for financial instruments; and |

| • |     | hired additional accounting, finance, operations, and information technology resources with relevant public company 
 experience, including a Chief Financial Officer, Controller and a Vice President of Information Systems.            |

We will not be able to fully remediate these material weaknesses until these steps have been completed and have been operating effectively for a sufficient period of time. Additionally, as stated above, we have not performed an evaluation of our internal control over financial reporting. Accordingly, we cannot ensure that we have identified all, or that we will not in the future have additional, material weaknesses. While we are aiming to complete these remediation efforts by the end of 2025, these remediation efforts or testing their effectiveness may extend into 2026. Material weaknesses may still exist when we report on the effectiveness of our internal control over financial reporting as required under Section 404 of the Sarbanes-Oxley Act, beginning with our second annual report after the completion of this offering. If we are unable to remediate the material weaknesses or if we identify additional material weaknesses in the future or otherwise fail to develop and maintain effective internal control over financial reporting, we may not be able to accurately or timely report our financial condition or results of operations, which may adversely affect our business. 127

Business

Business Overview BillionToOne is transforming healthcare by redefining molecular diagnostics. Our revolutionary single molecule NGS (smNGS) platform achieves what was once thought impossible—detecting and precisely quantifying genetic targets with single-molecule sensitivity. At the heart of this technological breakthrough lies our patented QCTs, enabling measurements at the physical limit of detection—the single DNA molecule. This leap forward addresses a fundamental limitation in healthcare—the inability to detect sparse but clinically crucial disease signals in cfDNA. Our superior technology platform has enabled us to build category-defining prenatal and oncology products. Our products reveal actionable insights from a simple blood draw that are fundamentally changing how diseases are diagnosed and treated, leading to a paradigm shift in personalized medicine