Company: BLLN
Filing Date: 2025-10-07
Form Type: S-1
Source: 0001193125-25-233697
Chunk: 231

Company: BillionToOne, Inc.
Filing Date: 2025-10-07
Form: S-1
Chunk 231
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, respectively. As of December 31, 2024, our clinician-focused sales organization included 137 sales representatives, with 120 in prenatal and
17 in oncology. In comparison, we had a total of 90 sales representatives at the end of 2023, 85 in prenatal and 5 in oncology. We plan to continue to expand our field sales force systematically, as our prenatal sales force is less than one-third the size of our largest competitor and our oncology sales force is very small relative to many other liquid biopsy companies. Our sales representatives in prenatal are engaged in educating OB-GYNs, MFMs, genetic counselors (GCs) and others about the existence, uniqueness and clinical utility of our offerings. Our sales representatives in oncology conduct similar commercial and educational activities
and primarily engage with oncologists. We have supplemented our direct sales team with medical science liaisons (MSLs) who are generally genetic counselors in prenatal and PhDs in oncology, as well as adding other support staff to help onboard
clinics and to manage the physician and patient experiences.

Our sales force achieved an annualized revenue run-rate of $1.8
million per sales representative in the six months ended June 30, 2025, despite approximately 35% of our territories launching less than 18 months ago. We believe our high sales efficiency is driven by the combination of our differentiated
products and our ability to provide a seamless, end-to-end solution that enhances both the patient and provider experience and significantly reduces churn. Our cohort
analysis indicates that the net test retention, as defined by the total number of tests that are received from a cohort of clinics first onboarded in a particular quarter, even after

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accounting for any account or provider churn, is over 100% after a year for the majority of quarterly cohorts. Our sales efficiency has also increased over time, and we believe this efficiency
will be maintained or further increase as we systematically grow our sales team.

We also drive physician awareness of our products by actively participating in
industry conferences, publishing in relevant scientific journals, and driving dialogue with key opinion leaders and physician organizations. These efforts have already resulted in practice advisory changes within the prenatal field, including for
RhD and fetal antigen NIPT. Across both prenatal and oncology, we believe that our ongoing and planned studies will help drive increased guideline expansion. Through our extensive digital marketing, we also engage directly with motivated patients,
and this can lead to access to physicians in clinics that typically