Phase Space Research

BillionToOne

BLLN · Investment summary · as of 4 August 2026

Priced below what the business already delivers

Portfolio decision
No position
Price · 4 August 2026
$137.32
12-month target
$161.00 +17%
Expected return
+17.3%
Next decision point
to August 2026Thesis resolution horizon

Business type: Inflection · scaling but economically observable

The operating path required by today's price is not achievable on the evidence.

Investment view

At $137.32, BLLN requires a 52% five-year revenue growth rate to justify its enterprise value — less than the business already delivers, at 98%.

The growth axis carries the larger slack (+46.14pp vs +16.92pp) and the disagreement with the market is about whether ~98% growth persists, not about the terminal margin.

The conditions that would settle the disagreement are dated to August 2026.

The value rests on an exit multiple of 13.1x, a terminal operating margin of 22% and a 9.0% cost of capital. Move any one of them materially and the conclusion moves with it, which is why the required-versus-demonstrated test above carries more weight here than the point value.

The strongest argument against this view: On 7 May 2026 Illumina, Inc. sued BillionToOne in the U.S.

Underwriting bridge

QuestionEvidence-based conclusion
What drives the business?The growth axis carries the larger slack (+46.14pp vs +16.92pp) and the disagreement with the market is about whether ~98% growth persists, not about the terminal margin.
What do we forecast?Revenue growth of 98% demonstrated; a terminal operating margin of 22%; an exit multiple of 13.1x.
What does Street forecast?Not determined — no consensus estimates are joined to this record
Where do we differ?On revenue growth, the difference between what the price requires and what the business has demonstrated is +45.6 percentage points.
What is it worth?Twelve-month target $161.00, +17% from the struck price. Scenario-weighted expected return net of costs +17.3%.
Why now?The first dated test of the thesis falls on 5 August 2026.

What must go right

  1. By 5 August 2026Q2-2026 revenue at or above $109.1m (consensus), and revenue growth ex prior-period true-ups below +60% YoY (it was +76.9% in Q1-2026 against an +84% headline)Where it stands: quarterly revenue and the disclosed prior-period figure in the revenue note
  2. By Q2-2026 and Q3-2026Revenue recognised for performance obligations satisfied in prior periods no more than 5% of quarterly revenue for a second consecutive quarter (it was 8.5% in Q1-2026)Where it stands: the prior-period revenue disclosure in the revenue note
  3. By Q2-2026 and Q3-2026Days sales outstanding at or below 55 days for two consecutive quarters, or accounts receivable growing more than twice as fast as revenue for two consecutive quarters (AR rose 47.3% QoQ against revenue +12.8% in Q1-2026; DSO went 39.8 -> 50.9 days)Where it stands: accounts receivable and revenue from the balance sheet and income statement

Catalysts and falsifiers

Date or windowEventThesis confirmed ifThesis weakened or refuted if
5 August 2026Quarterly revenue and the disclosed prior-period figure in the…Neither leg of the condition opposite is met at this dateQ2-2026 revenue below $109.1m (consensus), OR revenue growth ex prior-period true-ups below +60% YoY (it was +76.9% in…
Q2-2026 and Q3-2026The prior-period revenue disclosure in the revenue noteRevenue recognised for performance obligations satisfied in prior periods no more than 5% of quarterly revenue for a…Revenue recognised for performance obligations satisfied in prior periods exceeds 5% of quarterly revenue for a second…
Q2-2026 and Q3-2026Accounts receivable and revenue from the balance sheet and income…Days sales outstanding at or below 55 days for two consecutive quarters, or accounts receivable growing more than twice…Days sales outstanding above 55 days for two consecutive quarters, or accounts receivable growing more than twice as…
any quarter through the FY2026 10-K (~March 2027)Item 1 Legal Proceedings and the contingencies note; Item 9ANeither leg of the condition opposite is met at this dateAn adverse preliminary-injunction ruling in Illumina v. BillionToOne, OR a settlement carrying a royalty above 5% of…

Risk and sell discipline

Impairment case

On 7 May 2026 Illumina, Inc. sued BillionToOne in the U.S. District Court for the District of Delaware (No. 1:26-cv-00531), asserting US 10,612,096, US 12,139,760 and US 12,435,373 - patents on determining fetal fraction in maternal blood and identifying genetic variation in DNA mixtures - against the ENTIRE UNITY line: Fetal Risk Screen, Aneuploidy Screen, Fetal RhD and Fetal Antigen NIPT, and the newly launched UNITY Confirm. Reporting indicates the Quantitative Counting Template technology is the target. Relief sought includes an injunction. UNITY was 91% of FY2025 revenue and 89.1% of Q1-2026 revenue, so an adverse outcome sits on essentially the whole company, and Illumina is a direct prenatal competitor (via Verinata, named as such in BLLN's own 10-K) rather than a non-practising entity, which makes a licence-and-walk-away outcome less certain than it would otherwise be.

Estimated probability 22%, against the 18% level at which the position would be resized. It sits above that level, so this case could not be carried at full size.

Fundamental invalidation

Falsifiable and fundamental — not one of them is a price condition.

Price-based risk trigger

A daily close below $114.92 triggers an immediate review of the thesis and pauses additional buying. It is not an automatic sell unless a separate fundamental invalidation condition has been breached.

Upside sell discipline

Trim or exit for valuation and opportunity cost when the forward 12-month expected return falls below 0 net of costs, i.e. when price reaches the target. On approach to the $161.00 target the case is reviewed rather than added to; a target reached is a reason to re-examine the position, not to hold it by default. The position is trimmed once forward expected return falls below 0% net of costs, because the capital has a better use elsewhere in the book.

Investment criteria

CriteriaStatusInvestment meaning
QualityMetIs the business worth owning under its declared economic type?
ValuationNot metIs the operating path required by today's price achievable?
LiquidityMetCan the intended position be built and exited in the right vehicle?
DownsideMetOn 7 May 2026 Illumina, Inc. sued BillionToOne in the U.S.
MomentumNot determinedDoes price action support or complicate entry timing? Not established on the evidence on file.
CatalystMetIs there a dated event that resolves the disagreement?
ConsensusNot determinedIs the house-versus-Street disagreement identified and quantified? Not established on the evidence on file.

Quality, valuation and liquidity can prevent a position on their own. The remaining four inform timing, sizing and monitoring, and never reject an investment by themselves.

Bottom line

The strongest case for mispricing is that the business already delivers +45.6 percentage points more growth than the price requires. The most important unresolved uncertainty is the permanent-loss mechanism: on 7 May 2026 Illumina, Inc. sued BillionToOne in the U.S. The next evidence that should change the portfolio decision is the test dated 5 August 2026, or a daily close below $114.92, which forces an immediate review.