BLLN · BillionToOne
Conviction · Medium · more likely to lead the S&P 500 over the next three months, by a modest margin
Wrong if: a daily close below $94.44
Note written ·
Price against the kill line
11.3% clear of its kill line on the 13 November 2026 close.
How to read this
The red mark is the price level of the published kill line: a close through it (a weekly close, on a weekly line) would prove the research note wrong on price. The dot is where the stock closed on 13 November 2026; a dot left of the mark has closed through its line.
The scale is stretched near the line, so close calls are easy to see. More than 8% from the line, the stock reads well clear, with a hollow dot to show the figure is off the drawn scale.
The kill line is the research note's own test. The portfolio sells on business facts, not on a price. How the portfolio decides
Three months against the kill line
Daily closes, to . Red: the kill line, a daily close below $94.44, on record since 10 November 2026. The shares are up 12.0% since the close; the S&P 500 is down 2.1% over the same sessions. Figures in the note can cover a different window.
Kill line
A daily close below $94.44, the 13 October 2026 closing low, which would erase the rebound from October. Full-year 2026 revenue below the $460 million low end of guidance, or a fourth-quarter operating loss, would also show the case failing.
Research onlyNot in the portfolio.
Key figures from the filings · Health Care
Quarter to 30 September 2026, filed 4 November 2026; valuation at the 13 November 2026 close
- Revenue, latest quarter ($M)
- 123
- Revenue, change on a year (%)
- +47.2
- Gross margin (%)
- 70.9
- Operating margin (%)
- 9.0
- Free cash flow, four quarters ($M)
- 33.9
- Net cash, cash less debt ($M)
- 473
- Price to earnings (×)
- 114.4
- Enterprise value to sales (×)
- 11.9
All filed numbers
What BillionToOne reports to the SEC in its quarterly and annual filings. Each group states its period and filing date once; a figure dated otherwise says so. Built from the filings known on .
| Quarter to | Revenue ($M) | On a year (%) | Gross margin (%) | Operating margin (%) |
|---|---|---|---|---|
| first filed | 123 | +47.2 | 70.9 | 9.0 |
| first filed | 109 | +64.4 | 70.5 | 5.0 |
| first filed | 108 | +83.8 | 73.0 | 16.5 |
| first filed | 96.1 | +113.1 | 71.4 | 10.8 |
| first filed | 83.5 | +117.4 | 69.9 | 11.5 |
| first filed | 66.6 | — | 65.3 | −2.4 |
| Pre-tax income ($M) | 17.4 |
| Net income ($M) four quarters: 49.4 | 17.4 |
| Diluted shares, change on a year (%) against the quarter to 30 September 2025 | +245.1 |
| Operating cash flow ($M) | 47.9 |
| Capital spending ($M) | 14.0 |
| Free cash flow ($M) | 33.9 |
| Cash and short-term investments ($M) | 562 |
| Debt ($M) long-term debt | 89.0 |
| Net cash, cash less debt ($M) | 473 |
| Deferred revenue ($M) −29.6% on a year | 1.9 |
| Backlog, orders not yet delivered ($M) at 30 September 2025, filed 10 December 2025 | 4.7 |
| Receivables ($M) | 88.3 |
| Inventory ($M) | 21.9 |
| Shareholders' equity ($M) | 567 |
| Market value ($M) | 5,650 |
| Enterprise value, market value plus net debt ($M) | 5,177 |
| Enterprise value to sales (×) | 11.9 |
| Enterprise value to operating income (×) | 115.8 |
| Price to earnings (×) | 114.4 |
| Price to book value (×) | 10.0 |
| Free-cash-flow yield (%) | 0.6 |
Short interest (FINRA, settled 15 October 2026, published 26 October 2026): 5.5% of shares outstanding sold short, 5.5 days of average trading to cover, +4.0% since the previous report.
| Window | Bought | Sold |
|---|---|---|
| 90 daysfrom | $0 | $26.7M |
| 12 monthsfrom | $0 | $58.5M |
The thesis
BillionToOne is more likely than not to beat the S&P 500 over the next three months. The company beat and raised in its third-quarter report of 4 November 2026, and it is profitable with $561.5 million in cash. The fourth-quarter 2026 report, expected around March 2027, tests whether growth that slowed from 64% to 47% holds above the guided path.
Third-quarter revenue was $123.0 million, up 47% from $83.5 million a year earlier. Full-year 2026 revenue guidance rose to $460–470 million from $450–465 million. Prenatal testing revenue was $104.3 million (up 41%), oncology revenue was $17.1 million (up 96%), tests delivered were 206,000 (up 25%), gross margin was 71% and income from operations was $11.0 million, all per the 8-K filed 4 November 2026.
The shares closed at $110.79 on 12 November 2026, up 18.7% over three months and 26.4% below the 52-week intraday high of $150.44 set on 5 August 2026. They have drifted down from $114.95 on 9 November 2026 and sit above the 50-day average of $106.88 and the 200-day average of $97.54. The market is paying for continued profitable growth after a 36% drop that followed the second-quarter report in August, as one outlet reported.
Bullish and bearish views on BillionToOne, Inc.
The bull case on BillionToOne, Inc. (BLLN), in brief: the quarter beat and guidance rose. The bear case: growth is slowing.
Bull case
- The quarter beat and guidance rose. Revenue of $123.0 million compares with $109.4 million in the second quarter. The company describes the raised 2026 guide as 51% to 54% growth over 2025.
- Profit is larger and the company says it will last. Income from operations was $11.0 million in the third quarter, against $5.5 million in the second quarter and $9.6 million a year earlier. Net income was $17.4 million, or $0.32 per diluted share. The company said it expects profitability "similar to current levels, even with significant continued investments."
- Oncology is still nearly doubling. Oncology revenue was $17.1 million, up 96% from $8.7 million, per the 8-K. A peer-reviewed study reported on 7 October 2026 found the tissue-free Northstar Response test matched a tumor-informed assay on tumor-burden direction in 67 of 71 sequential pairs (94%).
- Sell-side targets sit above the price after the report. JPMorgan raised its target to $135 with an Overweight rating on 5 November 2026. BTIG reiterated Buy with a $130 target the same day. Piper Sandler kept Overweight on 10 November 2026 with a $130 target.
- Cash funds the growth. Cash and equivalents were $561.5 million at 30 September 2026, per the company's results release.
Bear case
- Growth is slowing. Revenue growth fell to 47% from 64% in the second quarter. Tests delivered rose 25% against 35%, and oncology growth eased to 96% from 176%.
- Part of the beat was one-time. An independent earnings review (finsee.ai) reported a $7.6 million revenue true-up from one payer in the third quarter. The same review calculates that the guidance midpoint implies fourth-quarter growth of about 29%. The company says guidance includes true-ups already booked this year and excludes any in the fourth quarter.
- Insiders keep selling. Chairman and CEO Oguzhan Atay sold 30,335 shares at an average of $109.93 on 2 November 2026, and CTO David Tsao sold 20,000 shares at an average of $109.24 the same day, both under Rule 10b5-1 plans (SEC Form 4, filed 4 November 2026). Atay also sold 11,000 shares at $118.00 on 28 October 2026. A director's Form 4 filed 12 November 2026 reports an other acquisition or disposition of 614,358 shares on 9 November 2026.
- One analyst lowered a target after the report. Piper Sandler lowered its price target to $130 on 10 November 2026 while keeping Overweight.
- The shares are fading from the post-report high. The close slid from $114.95 on 9 November 2026 to $110.23 on 11 November 2026 before $110.79 on 12 November 2026.
- The August drop is not fully explained. The shares fell sharply after the second-quarter report of 5 August 2026, which one outlet attributed to a beat with no guidance raise. The raise in November addressed that complaint, but the market has not yet rated the slower growth.
Price setup
The last close is $110.79 (12 November 2026). The 50-day average is $106.88 and the 200-day average is $97.54, both on adjusted closes as of that date. The 52-week intraday high is $150.44 (5 August 2026), and the 52-week closing low is $64.03 (12 March 2026).
The three-month reference close was $93.33 on 14 August 2026, so the 18.7% gain covers the period after the August drop. The October low, a closing low on 13 October 2026, is the level below which that rebound would be erased.
The company listed on Nasdaq on 6 November 2025, so ranges and averages cover about a year of trading.
Catalysts ahead
- ~1 March 2027 (est.): Fourth-quarter and full-year 2026 results report (date not yet announced). Shows whether revenue lands inside the $460–470 million guided range, whether growth holds above the roughly 29% fourth-quarter rate an independent review calculates, and whether operating income stays positive.
What would change the view
A daily close below $94.44, the 13 October 2026 closing low, which would erase the rebound from October. Full-year 2026 revenue below the $460 million low end of guidance, or a fourth-quarter operating loss, would also show the case failing.
The risks this note tracks, each with what would confirm it:
- Revenue growth keeps slowing toward the roughly 29% fourth-quarter rate that an independent review calculates from the guidance midpoint. Confirmed by: a fourth-quarter report with revenue growth below 30% or full-year revenue below the $460 million low end of guidance.
- The third-quarter beat leaned on a one-time payer true-up, so underlying revenue is weaker than the headline. Confirmed by: management saying on the fourth-quarter call that the $7.6 million true-up explains most of the third quarter's upside.
- Operating expenses rise faster than revenue and erase the $11.0 million quarterly operating income. Confirmed by: an operating loss or sharply lower income from operations in the fourth-quarter report.
- Continued insider selling under Rule 10b5-1 plans caps the rebound. Confirmed by: further Form 4 sales by executives following those filed 4 November 2026 for sales on 2 November 2026.
- Final CMS 2027 lab fee rates reverse the favourable preliminary changes. Confirmed by: a final CMS clinical laboratory fee schedule that cuts rates for BillionToOne tests.
What it trades with
BillionToOne trades with prenatal and cancer diagnostics peers and with growth-oriented healthcare shares more than with the broad market. CareDx was named alongside it in the 23 September 2026 Benzinga report on Medicare lab fee changes, and Centers for Medicare & Medicaid Services (CMS) rate decisions move both. Earnings reactions have been large in both directions: the shares fell sharply after the second-quarter report on 5 August 2026 and rose after the third-quarter report on 4 November 2026.
The evidence, claim by claim (8)
- Third-quarter 2026 revenue was $123.0 million, up 47% from $83.5 million; prenatal revenue $104.3 million (up 41%), oncology $17.1 million (up 96%), 206,000 tests delivered (up 25%). BillionToOne third-quarter 2026 results, Form 8-K · as of
- Income from operations was $11.0 million versus $9.6 million a year earlier; net income $17.4 million, $0.32 per diluted share; gross margin 71%. BillionToOne third-quarter 2026 results, Form 8-K · as of
- Full-year 2026 revenue guidance raised to $460–470 million (51% to 54% growth) from $450–465 million. BillionToOne third-quarter 2026 results, Form 8-K · as of
- Cash and cash equivalents were $561.5 million. BillionToOne third-quarter 2026 results release · as of
- Second-quarter revenue was $109.4 million, up 64%, with operating income of $5.5 million. BillionToOne second-quarter 2026 results release · as of
- JPMorgan raised its price target to $135 with an Overweight rating; BTIG reiterated Buy with a $130 target. JPMorgan and BTIG analyst notes, company news · as of
- Piper Sandler maintained Overweight on BillionToOne and lowered its price target to $130. Analyst-action news, Piper Sandler · as of
- CEO Oguzhan Atay sold 30,335 shares at an average of $109.93 and CTO David Tsao sold 20,000 shares at an average of $109.24 on 2 November 2026 under Rule 10b5-1 plans. SEC Form 4 filings filed 4 November 2026 · as of
Sources
- BillionToOne, Inc. - Form 8-K - FY2026 · sec.gov ·
- BillionToOne (BLLN) Q3 2026 earnings review · finsee.ai
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