Company: BLLN
Filing Date: 2025-10-07
Form Type: S-1
Source: 0001193125-25-233697
Chunk: 146

Company: BillionToOne, Inc.
Filing Date: 2025-10-07
Form: S-1
Chunk 146
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 the Overall ASP for our tests. Achieving guideline inclusion is a benefit for patients, and it is a significant catalyst for expanded reimbursement which can further elevate our ASPs. We believe ASP can increase further over time with expansion of contracting & coverage. ASP Further contracting from ~225M to ~300M lives Increased RhD and sgNIPT coverage Response MolDx coverage 22q guideline inclusionExpanded panel guideline Select ADLT pricing via FDA approval PRENATAL ONCOLOGY

| • |     | Internalizing and strengthening our reimbursement capabilities & incorporating automation and AI to 
 reimbursement operations:                                                                           |

To further optimize our reimbursement outcomes, in July 2023, we transitioned from relying on third-party vendors to managing our reimbursement function in-house.We have invested in building a high-performing, specialized team dedicated to all aspects of reimbursement, including claims management, appeals, and payor relations. This team’s expertise and commitment have enabled a more consistent, and accurate billing and appeal process, along with the rapid identification and resolution of reimbursement issues. Since bringing this capability in-house,we have achieved dramatically improved results, evidenced by a significant and sustained increase in ASPs over the past two years. 98

In addition, we have integrated our internal systems end-to-end,automated many of the repetitive reimbursement procedures, and incorporated AI for significant efficiency improvements (e.g., using large language models (LLMs) to read, categorize, and react to thousands of correspondence from insurance companies that we receive every day), allowing our team to significantly increase their productivity. For example, this has allowed us to respond to or correct 50% more claims by insurance companies with only a 15% corresponding increase in headcount. This strategic move not only streamlines our operations and improves cash flow but also allows us to better advocate for the value of our diagnostic tests with payors by providing rapid feedback and responding proactively to evolving reimbursement trends.

| • |     | Relentless focus on reducing costs and increasing operational efficiency |

Our financial results depend upon our ability to support current and future levels of demand for our prenatal screening and oncology diagnostic tests while maintaining discipline around our cost structure. Historically, we have been able to grow the size of our operational team much more slowly than our test volume increases. This has led to significantly increased operational leverage and efficiencies on a per-testbasis and has been a driver in improving our net loss margin. We actively seek ways to continuously reduce our costs-per-testand improve our gross profit margin, long-term profitability, and return