BillionToOne (NASDAQ:BLLN) shares drop 39% after maintained guidance signals weaker second half

BillionToOne (NASDAQ:BLLN) shares drop 39% after maintained guidance signals weaker second half

NEW YORK, August 6, 2026, 15:06 EDT (00:06 PKT, August 7) — U.S. cash trading begins.

  • The stock was last at $91.72, falling 38.84%. Trading volume was almost four times higher than its 65-day average.
  • Revenue for the second quarter increased by 64% to $109.4 million. The company maintained its full-year forecast at $450 million to $465 million.
  • The outlook suggests growth in the second half will range from about 29% to 38%. Revenue in the first half increased by 74%.

BillionToOne stock slid 38.8% to $91.72 as of 3:03 p.m. The company maintained its 2026 sales forecast following a robust quarter. Based on basic shares as of August 3, the decline wiped out approximately $2.75 billion in market capitalization.

Stock chart for NASDAQ:BLLN

The development was primarily related to the company. The Nasdaq showed little change, while the SPDR S&P Biotech ETF (NYSEARCA:XBI) rose approximately 0.3%.

The market was not dismissing the quarterly results but was instead adjusting valuations for the second half’s exit rate. Using the guidance midpoint, mean quarterly revenue in the back half is just 9.5% higher than in the second quarter.

Implications of maintaining guidance

MeasureRevenue or growthInvestor read-through
First-half 2026 revenue$217.8 millionGained 74% compared to previous year
Full-year guidance$450 million-$465 millionIncrease of 48%-52%
Second-half revenue required$232.2 million-$247.2 millionFigures come from company guidance
Implied second-half growth29.4%-37.7%Significant drop in pace versus first half
Average second-half quarter$116.1 million-$123.6 millionAt the midpoint, that’s 9.5% higher than Q2

The numbers for the second half are derived calculations and not distinct guidance provided by the company.

The significance of that trajectory is underscored by BillionToOne’s gain of over 84% following its May earnings. Shares ended Wednesday at $149.97, just below the record high of $150.44. Investor expectations were already elevated.

The quarter demonstrated solid operational performance. Test volume expanded by 35%, and the average selling price went up 21%. Gross margin stood at 70.5%, with operating profit at $5.5 million.

Oncology continued as the unit with the strongest growth, posting revenue of $13.7 million, up 176%. Revenue from prenatal clinical services climbed 55% to $94.2 million.

Operating results by quarter

MetricQ2 2025Q1 2026Q2 2026
Tests performed145,000188,000196,000
Average selling price excluding true-ups$440$522$537
Average selling price reported$455$571$551
Total revenue$66.6 million$108.4 million$109.4 million
Gross profit margin65.3%73.0%70.5%
Operating income/(loss)$(1.6) million$17.8 million$5.5 million
Adjusted EBITDA$2.9 million$26.0 million$16.1 million

Revenue was up just 1% from the previous quarter, but rising 8% when excluding reimbursement true-ups. BillionToOne retained over $10 million in claims amid national-payor code modifications.

Core pricing advanced, with ASP excluding true-ups increasing by $15 compared to the first quarter, supported by recent payor agreements. The data indicate that headline revenue did not fully reflect underlying sequential gains.

Chief Executive Oguzhan Atay said, “Our second quarter demonstrated the durability of our model.” The company intends to launch a 130-gene fetal-risk panel on August 17. Northstar Origin remains set for September 1. BillionToOne Inc.

Same-day shifts among peers clarified the direction of guidance.

Molecular-diagnostics profit comparison

CompanyQ2 revenue growthQ2 profitabilityKey updateAugust 6 stock move
BillionToOne 64%Net income of $8.1 millionMaintained guidance between $450 million and $465 million-38.8%
Caris Life Sciences 45%Net loss of $0.6 millionGuidance increased to a range of $1.03 billion to $1.04 billion+16.4%
GRAIL 26%Net loss of $110.2 millionFDA advisory committee review set for autumn-17.2%

Movements tracked between 14:50 and 15:03 EDT.

Caris shares surged even though its growth lagged behind BillionToOne. The company lifted its outlook. The difference highlights investors’ strong focus on future guidance.

Matt Larew, an analyst at William Blair, described BillionToOne as “a victim of its own success.” BTIG analyst Mark Massaro kept his Buy rating but lowered his price target to $130 from $142. That revised target still remained 42% higher than the current share price. Investor’s Business Daily

Latest analyst ratings

DateFirm and analystRatingPrice targetAction
August 6, 2026BTIG — Mark MassaroBuy$130Reduced from $142
June 29, 2026Guggenheim — Subbu NambiBuy$125Started coverage
May 7, 2026JPMorgan — Casey WoodringOverweight$125Lifted from $120
March 5, 2026Wells Fargo — Brandon CouillardEqual Weight$90Lowered from $110
December 1, 2025Stifel — Daniel AriasBuy$145Started coverage
December 1, 2025Jefferies — Tycho PetersonHold$117Started coverage

According to MarketWatch’s FactSet data, there were six Buy recommendations and two Holds. The mean price target stood at $121.43, representing a roughly 32% premium to the current share price. Analyst forecasts may shift again following Thursday’s decline.

Valuation is still high. With basic shares at $91.72, equity is valued at approximately $4.33 billion. Subtracting $548.6 million in cash and adding $91 million in debt, enterprise value stands at about 8.5 times the midpoint of projected 2026 revenue.

Risks: Over 90% of first-half revenue came from third-party reimbursement. Accounts receivable increased 80% since December, reaching $74.9 million. Accelerating oncology growth could squeeze margins, as those tests are less profitable at present.

Upcoming tests are approaching fast. Investors are set to monitor the August and September launches, as well as reimbursement collection and ASP figures without true-ups. Most importantly, they seek proof that the current guidance is cautious—not an indication of stalled growth.

TS2 TECH • EXTENDED COVERAGE

Further analysis

What caused BillionToOne's shares to fall by roughly 39% despite reporting robust results?
BLLN shares fell roughly 39% on August 6 after the company maintained its existing guidance. The projected 2026 revenue remains between $450 million and $465 million, signaling expected growth of 29%–38% for the second half, compared to 74% growth in the first half. Future true-ups are still not included due to uncertain timing and collections. Market expectations had been elevated, as the stock had climbed more than 84% since May 6.
Did second-quarter revenue actually remain unchanged from the previous quarter?
No. Reported revenue climbed just 1%, from $108.4 million to $109.4 million. True-up revenue dropped from $9.2 million to $2.8 million. Excluding true-up revenue, revenue advanced 8% sequentially. Test volume rose 35% compared to a year earlier. The top-line result did not reflect stronger performance in the current quarter.
What is the extent of collection risk underlying the stated revenue?
By June 30, accounts receivable climbed 80% to $74.9 million. BillionToOne reported more than $10 million in claims outstanding during payer-code implementation. Management is unable to provide certainty on the amount or timing of final collections. More than 90% of revenue for the first half was generated through third-party reimbursement. Operating cash flow for the first half remained positive at $24.6 million.
Is it possible for oncology to drive additional growth without impacting margins?
Oncology revenue increased 176% to $13.7 million, accounting for roughly 13% of total sales. Gross margin stood at 70.5%; operating margin declined to 5%. Management cautioned that rapid oncology growth might temporarily drag gross margin below 70%. Northstar Response contributed nearly two-thirds of oncology test volume. MolDX coverage is targeted by year-end, but approval is still not guaranteed.
Khadija Saeed

Khadija Saeed is a financial markets reporter at TS2.tech, specializing in stocks, technology and emerging industries. She studied economics and finance at the London School of Economics and previously worked in market research before moving into financial journalism. Her coverage focuses on the companies, innovations and economic trends influencing global investors. Follow Khadija Saeed on Google News.

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