Finvest
BLLN Diagnostics · Molecular testing · Prenatal · Oncology · Thesis updated July 19, 2026

Volume is turning tests into profit

01 Running thesis

The flywheel is working

BillionToOne is a diagnostic testing company where scale matters. More doctors order its tests, more tests flow through its labs, and more volume gives the company a stronger case when it negotiates with insurers. That can raise the average selling price, which is the amount the company gets paid per test, and it can lower claim denials.

The recent numbers show that operating leverage, which means profit rising faster than sales, is showing up. Q1 2026 net income was $18.0M, more than the $7.5M the company earned in all of FY2025. Gross margin also rose to 73% in Q1 2026 from 64% a year earlier.

The bull case is that prenatal testing funds the business while oncology becomes the next growth leg. Oncology was 10% of Q1 2026 revenue, up from 8% in FY2025, and new Northstar PGx and CH add-ons give doctors more reasons to use Northstar Select.

The bear case is simple: insurers control the cash. More than 90% of revenue comes from third-party payors. If Medicare or commercial insurers slow coverage, deny more claims, or ask for money back, the profit story can change fast.

May 2026Q1 2026 showed a sharp profit step-up. Gross margin reached 73%, and net income of $18.0M topped the $7.5M earned in all of FY2025.
May 2026Management said the Anthem contract lifted contracted U.S. lives to about 300 million. It also said the MolDX review for Northstar Response was moving within the 60-day timeline and showed no delay.
Mar 2026FY2025 confirmed the company had crossed into annual profitability, with $7.5M of net income and gross margin of 68%. Annual test volume reached about 616,000.
Dec 2025The first thesis build showed a fast-growing diagnostics platform, with 95% year-over-year revenue growth for the nine months ended September 30, 2025. It also flagged third-party payor dependence as the core risk.
02 Business model

Paid when insurers agree

BLLN performs molecular diagnostic tests ordered by doctors and other health providers. It usually bills the patient's insurance carrier, the patient, or both after delivering the test result.

The company runs on its single-molecule next-generation sequencing platform, or smNGS. In plain English, that is a lab method that counts tiny pieces of genetic material with high precision. The same core technology supports both prenatal testing and cancer testing.

The model depends on a payor flywheel. Higher test volume can help BLLN sign in-network contracts, which can improve payment rates and reduce denials. In Q1 2026, management said the Anthem contract brought total contracted lives to about 300 million in the United States.

This is also where the model can break. A test can be useful to doctors but still fail as a business if insurers say it is not medically necessary, dispute the billing code, or demand repayment after an audit.

03 Product portfolio

Prenatal today, cancer tomorrow

Cash cow

UNITY

UNITY is the core prenatal test line. It is a single-gene non-invasive prenatal test for recessive conditions and remains the main revenue base.

Growth engine

Unity Aneuploidy

Unity Aneuploidy is the frontline prenatal screen that management wants more patients to use. Its value rose after Unity Confirm became available only to patients who start with this test.

Option

Unity Confirm

Unity Confirm launched in May 2026 as a circulating fetal cell-based confirmation assay. Management expects little direct revenue from it, but sees it as a way to make Unity Aneuploidy stand out.

Growth engine

Northstar Select

Northstar Select is a pan-cancer liquid biopsy used to help select therapy. BLLN added Northstar PGx in January 2026 and Northstar Select CH in February 2026.

Growth engine

Northstar Response

Northstar Response measures tumor burden and therapy response without a tissue biopsy. Medicare coverage is a key near-term catalyst, and management said the MolDX review was moving on schedule.

Steady

Clinical trial support

Clinical trial support is small today, at 1% of Q1 2026 revenue. It can help show drug companies how the testing platform works, but it is not the main business.

04 Business segments

Still mostly prenatal

Prenatal tests89%modest
Oncology tests10%growing fast
Clinical trial support services1%flat

The mix below is from the three months ended March 31, 2026. Third-party payor reimbursement is the larger concentration issue, since it represents over 90% of total revenue.

05 Risk factors

What could break

Payor reimbursement shock

High impact · Medium odds

BLLN depends on insurers and government payors for most of its cash. Third-party payors represent over 90% of revenue. If payors deny more claims, dispute codes, or demand recoupment, revenue and margins could fall even if test demand stays strong.

We watchTrack denial rates, average selling price per test, new in-network contracts, and any disclosed recoupment demands.

Northstar Response coverage stalls

High impact · Medium odds

The oncology story needs broader coverage for Northstar Response. Management said the 60-day MolDX process was moving without delay and could finish earlier than expected, but that is not the same as permanent commercial adoption. If Medicare or large commercial payors hesitate, the oncology mix may stop rising.

We watchWatch for the MolDX decision, Medicare payment language, and commercial coverage policies for Northstar Response.

Prenatal concentration stays too high

Medium impact · Medium odds

Prenatal tests were 89% of Q1 2026 revenue. That makes BLLN less diversified than the Northstar growth story suggests. If prenatal growth slows before oncology scales, the company could lose the volume leverage that supports margins.

We watchWatch quarterly revenue mix, prenatal volume growth, and whether oncology keeps moving above 10% of revenue.

Growth strains lab operations

Medium impact · Medium odds

Fast volume growth can stress lab capacity, billing teams, and quality control. Test volume accessioned reached about 189,000 tests in Q1 2026, so small process problems can become big cost problems. The planned Austin lab opening in 2028 could also weigh on margins before it adds enough capacity.

We watchMonitor gross margin, turnaround times, lab spending, hiring pace, and Austin lab construction updates.

Coverage does not equal cash

Medium impact · Medium odds

Being in network with about 300 million U.S. lives is a strong selling point, but it does not guarantee full payment on every test. Insurers can still apply medical necessity rules and prior authorization. BLLN must keep proving that its tests improve care enough to justify payment.

We watchCompare contracted lives against actual collected revenue, average selling price, and bad debt or allowance trends.
06 Quick answers

In one breath

What does BillionToOne actually sell?

It sells molecular diagnostic tests, mainly prenatal tests and cancer blood tests. Doctors order the tests, BLLN runs them in its labs, and the company bills insurance carriers, patients, or both.

Why is insurance coverage so important for BLLN?

More than 90% of revenue comes from third-party payors. If insurers pay faster and deny fewer claims, growth can turn into profit. If they push back, the same test volume may be worth much less.

Why does oncology matter if prenatal is most of revenue?

Prenatal is the base business, but oncology is the expansion story. Oncology was 10% of Q1 2026 revenue, and Northstar Response coverage could help that mix rise over time.

What is the biggest near-term catalyst?

Medicare coverage for Northstar Response is the key item to watch. Management said the MolDX review was moving within the 60-day timeline and showed no sign of delay.