BillionToOne, Inc. (BLLN) stock intrinsic value fair value estimate & owner earnings analysis

BillionToOne sells blood-based molecular tests built on its single-molecule counting sequencing technology. In 2025, 91% of its $305.1 million of revenue came from prenatal tests (UNITY, including fetal screening for recessive conditions and the 22q deletion add-on), 8% from the Northstar Select and Northstar Response cancer tests and 1% from services. Over 90% of revenue is reimbursement from US insurers and government payors, and almost all of it is earned in the United States. Revenue doubled in 2025 on a 51% rise in billable tests (to about 610,000) and a 35% rise in the average price per test, helped by new payor contracts and a proprietary billing code adopted in the second half of 2024. Its competitors are large and well-funded: Natera, Labcorp, Illumina's Verinata, Myriad and Quest in prenatal; Guardant, Exact Sciences, Grail and Natera in cancer testing. Earnings level. The company only turned cash-positive in 2025. Measured as operating cash flow excluding swings in receivables and inventory, after charging stock compensation as a real cost and after only the capital spending needed to maintain the labs, owner earnings were about -$68 million in 2023, -$38 million in 2024 and +$25 million in 2025 (about $0.46 per share on today's roughly 54.5 million diluted shares; earlier years' share counts predate the IPO and preferred conversion, so all years are shown on today's count). Lease payments were treated as an ongoing cash cost. 2025 includes about $7.8 million of interest earned on IPO cash; we exclude that interest from the business figures because the cash itself is counted separately. With only one positive year there is no median to take, so the level rests on the first half of 2026, which is two profitable quarters: operating income of $23.3 million on $217.8 million of revenue. The two quarters were not alike: revenue was flat from the first quarter ($108.4 million) to the second ($109.4 million), gross profit slipped and operating income fell from about $17.8 million to $5.5 million as spending rose. We therefore set the business's normal cash earnings before lender payments at about $40 million a year, between the second-quarter run rate and the first-half average, rather than annualizing the best quarter. Stock compensation is rising quickly (about $29 million annualized in 2026 versus $16 million in 2025), and that is already charged in this figure. Growth credited. None in the base case. The volume gains of the past two years came from sales force expansion and taking share, and the price gains from new payor contracts and a new billing code. Both are real, but they are share gains and pricing wins rather than a long, proven, self-funded repeatable process, and the business only reached profitability in 2025. The flat second quarter supports not extrapolating them. Patented technology and payor contracts are what keep earnings going; with no evidence of a durable product replacement engine yet, earnings are held flat for ten years and then faded to zero over the following ten. Debt and cash. At June 30, 2026 the company held $548.6 million of cash. It owes Oberland Capital notes: $50 million drawn in August 2024 plus a $30 million tranche it was required to draw before March 31, 2026, carrying 8% interest plus revenue participation payments, with a lump sum in August 2031 sized to give the lender a 10% return. Because that is well above a long-bond rate, we carry the debt at about $95 million, close to its $91.0 million reported fair value, plus about $3 million of finance leases. After holding back $50 million as working cash, net cash is about $400 million, or roughly $7.35 per share. The 2031 maturity is easily covered by today's cash. Base case ($14.26). Business cash earnings of about $40 million a year for ten years, then fading to zero over the next ten. Business worth about $376 million, plus about $400 million of net cash, divided by 54.5 million shares. Bear case ($10.46). Prenatal testing has a history of sharp price resets: after 2015-2016, when screening widened to average-risk pregnancies and competitors fought on price and payor coverage, per-test prices across the industry fell steeply for several years. The bear case repeats that: the higher-paying billing code and contracted rates are pressured by insurers, by claw-backs of previously paid claims (a risk the company itself flags) and by Medicare rate resets under the PAMA law that have been repeatedly delayed but not repealed. Cash earnings drop from about $30 million to $5 million a year in years three and four, below the roughly $6.4 million interest bill for two years (cash covers it), then recover to $25 million and fade out after year ten. Business worth about $169 million plus $400 million of net cash, or $10.46 per share. Even here the cash balance supports the shares; the company owes far less than it holds. Bull case ($26.87). The company's own levers keep working: cash earnings start near the first-half 2026 pace of about $55 million and grow 15% a year, slowing to zero growth by year ten as sales force expansion and cancer-test volume keep adding, reaching about $106 million, held for five years and then faded. Business worth about $1.06 billion plus $400 million of net cash. Margin-of-safety price ($10). How sure are we of the earnings level? Not very: there is one profitable year and two profitable quarters, and the second quarter showed revenue stalling and costs rising. What is the worst plausible outcome? A reimbursement reset or a payor recoupment that sends the business back to losses while it keeps spending on growth, burning the cash pile. The structure helps here: the cash is more than five times the debt, the debt does not mature until 2031, and there are no customer concentrations among individual insurers disclosed as material. What could we be most wrong about? If the price per test falls back toward pre-2024 levels the business is worth little beyond its cash, about $7 to $9 per share; if stock compensation keeps growing faster than revenue, normal earnings sit nearer $25 million and the shares are worth about $12. What does the business pay in the meantime? Nothing; there is no dividend, and shareholders are being diluted by stock awards. A price of $10 is roughly the bear case, with about $7.35 per share of that backed by net cash, and a move to the base case within two to three years, together with any growth beyond the base case, gives a credible route to a 20% annual return from that price. Above that, too much of the return depends on growth we cannot yet credit. This analysis is not comparable with our previous estimate, which credited several years of rapid revenue and margin growth that has not yet been earned; since then the business has also delivered two profitable quarters but with clear slowing in the second quarter.