$314,025,900 | BillionToOne (logo) Initial Public Offering | November 2025

William Blair acted as a joint active bookrunner on the $314.0 million initial public offering for BillionToOne, Inc. (Nasdaq: BLLN), a high-growth, commercial-stage precision diagnostics company transforming healthcare through its proprietary single-molecule next-generation sequencing (smNGS) platform. Through smNGS, BillionToOne detects and quantifies blood-based biomarkers with single molecule sensitivity and precision and has applied this technology to the non-invasive prenatal testing and oncology liquid biopsy markets. Key transaction details are outlined below:

  • Priced an upsized $273.1 million IPO at $60.00 per share, $5.00 above the top of the initial filing range of $49.00 - $55.00
  • Base deal upsized from 3.8m shares to 4.6m shares (+18%) on the back of strong demand
  • Over 200 investor touchpoints across a 6-day virtual roadshow and group lunch, resulting in a 90%+ hit rate
  • Final orderbook was over 25x oversubscribed across 300+ orders, with significant anchor-level demand from long-only investors and healthcare- dedicated funds
  • BillionToOne intends to use the net proceeds from this offering for working capital and other general corporate purposes, including to fund growth, research and development initiatives, technology development, working capital, and operating expenses
  • Successfully executed IPO despite government and SEC shutdown by leveraging 20-day automatic effectiveness

We would be happy to further discuss the transaction as well as the current conditions in the U.S. equity capital markets. Please let us know if you are interested in scheduling a call with our team.

About the Company

BillionToOne is a high-growth, commercial-stage precision diagnostics company transforming the prenatal and oncology markets through its proprietary single-molecule next-generation sequencing (smNGS) platform. Through smNGS, the company has developed ultrasensitive tests that can detect sparse, yet clinically relevant, disease signals in cell-free DNA (cfDNA), reaching the physical limit of detection from a single blood draw. In 2019, BillionToOne entered the prenatal testing market via the launch of UNITY, which consists of three non-invasive prenatal testing screens offered through the UNITY Complete Fetal Risk Screen. This test is the first and only single-gene non-invasive prenatal test (sgNIPT) that uses cfDNA to provide precise fetal risk assessments for recessive conditions and fetal red blood cell antigens without requiring a paternal sample. It also reports fetal aneuploidy and 22q11.2 microdeletion, enabling broad genetic insights from a single maternal blood draw. In 2023, BillionToOne entered the oncology market with two complementary products that leverage the smNGS platform. Northstar Select, an ultrasensitive liquid biopsy test, provides insight into therapy selection for stage III or IV cancer patients. Northstar Response, the only tissue-free, smNGS-based, pan-cancer liquid biopsy test, precisely measures genomic loci to provide insights into the patient’s response to therapy. The company is scaling rapidly and benefitting from both commercial success and operational efficiency gains. To date, BillionToOne has processed more than one million smNGS-based tests.

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