BillionToOne, Inc.

Overview

BillionToOne, Inc. is a U.S.-based precision molecular diagnostics company whose proprietary technology measures DNA at the single-molecule level. Its core business spans prenatal screening and oncology liquid-biopsy testing: UNITY assesses fetal genetic risk using maternal blood, while Northstar Select and Northstar Response support cancer-treatment selection and response monitoring.[1]+2 The company’s stated mission is to “remove the fear of the unknown” through accessible molecular diagnostics.[2]

Founded in 2016 and headquartered in Menlo Park, California, BillionToOne’s reported market reach is primarily U.S.-focused; it says it has tested more than one in ten U.S. pregnancies.[1]+2 Revenue was $217.8 million for the six months ended June 30, 2026.[5] The company’s milestones page reported more than 500 employees in 2024, a historical—not current—headcount.[6] [1]+6

Products & services

BillionToOne’s products use its single-molecule next-generation sequencing (smNGS) platform, which applies quantitative counting templates to detect and quantify genetic targets at single-molecule sensitivity, including low-abundance signals in cell-free DNA. Its prenatal portfolio includes UNITY, a non-invasive prenatal test that uses a maternal blood sample to assess fetal risk for recessive conditions such as sickle cell disease and cystic fibrosis without requiring a paternal sample. The company announced an expansion of the UNITY Fetal Risk Screen to a 130-gene panel, with commercial availability planned for August 17, 2026. Unity Confirm, launched in May 2026, captures intact circulating fetal cells from maternal blood to confirm high-risk screening results without an invasive prenatal procedure.[7]+3

Its oncology portfolio includes Northstar Select, a pan-cancer liquid biopsy intended to identify tumor-specific variants and inform therapy selection, and Northstar Response, a methylation-based assay that measures tumor burden to monitor treatment response. The company reports that Select can detect actionable mutations at low variant allele frequencies; in a head-to-head study, it detected 51% more single-nucleotide variants and 109% more copy-number variants than comparator assays. Northstar PGx and Northstar Select CH are add-on applications addressing chemotherapy safety and clonal hematopoiesis, respectively; Northstar Origin is an add-on feature intended to help identify tissue of origin when diagnosis is uncertain.[10]+4

For the six months ended June 30, 2026, prenatal tests accounted for approximately 88% of revenue and oncology tests 11%, with clinical-trial support and other services making up the remaining 1%. The company was also developing a tissue-free, pan-cancer minimal residual disease test to detect trace tumor DNA after curative-intent surgery; its Q2 2026 filing anticipated commercial availability in Q4 2026.[15][12] [7]+12

Geographic presence

BillionToOne is headquartered in Menlo Park, California, and operates offices and laboratories in Menlo Park and Union City, California. Nearly all of its revenue was associated with tests performed at the Union City laboratory, with a small percentage from the Menlo Park laboratory; no geographic revenue percentages or country-by-country breakdown are reported.[1]+2

The company has a broad U.S. reach: its Union City laboratory was enrolled as a Medicaid provider in more than 40 states, and the company reported testing more than one in ten babies during pregnancy in the United States.[18][2]

BillionToOne has planned an Austin, Texas, office and laboratory facility. Its disclosures describe a lease expected to commence by September 30, 2027, and the Austin laboratory as a prospective third lab expected to open in 2028.[19][17] The company reported 713 full-time employees but did not disclose their geographic distribution.[20] [1]+6

Business segments

BillionToOne reports one operating segment and one reportable segment; its CEO, as chief operating decision maker, reviews financial information on a company-wide basis. Prenatal and oncology testing are therefore business lines, not separately reported segments.[21][22]

Within that single-segment structure, the company’s service categories include prenatal testing, oncology testing, and clinical-trial-support services. Prenatal testing includes the UNITY product line; oncology offerings include Northstar Select and Northstar Response.[23]+2 For the first half of 2025, disclosed service-category revenue was approximately 93.1% prenatal ($116.9 million), 5.7% oncology ($7.1 million), and 1.2% clinical-trial support ($1.5 million), out of $125.5 million total. These are service-line shares, not reported segment contributions; the 2026 second-quarter disclosure did not provide a separate revenue mix.[26][27] [21]+13

Company history

BillionToOne was founded in 2016 by Oguzhan Atay and David Tsao. It began developing molecular diagnostic tests, with early work focused on prenatal screening. In 2019, the company launched UNITY, its prenatal screening product, and published a validation study that year.[28]+3

From 2019 to 2022, BillionToOne raised successive financing rounds and expanded UNITY’s prenatal screening offerings, including fetal-antigen screening. In 2022, it also introduced its Northstar liquid-biopsy tests for oncology research; the tests became available for clinical and commercial use in 2023.[28]+4

In 2024, Ross Taylor became CFO, and the company announced a $130 million Series D financing. In 2025, BillionToOne marked its one-millionth UNITY test, expanded the UNITY panel, and completed an initial public offering, with its shares beginning to trade on Nasdaq as BLLN. In 2026, it continued expanding both its prenatal and Northstar product lines.[33]+5

Sources

• BillionToOne, Inc. — Full financial report (2026 Q 2)
  10 citations

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• BillionToOne, Inc. — Ipo (2025 O)
  3 citations

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• www.billiontoone.com[6]
• investors.billiontoone.com[9]
• BillionToOne, Inc. — Ipo (2025 O)
  6 citations

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• www.billiontoone.com[13]
• www.billiontoone.com[14]
• BillionToOne, Inc. — Full financial report (2025 Y)
  9 citations

  [16][17][18][19][20][21][23][24][25]
• www.billiontoone.com[30]
• www.billiontoone.com[31]
• www.billiontoone.com[34]
• www.billiontoone.com[35]
• www.billiontoone.com[37]
• www.billiontoone.com[38]
• www.billiontoone.com[39]