BillionToOne [BLLN]
⚠️ SUPERSEDED IN PART — 2026-07-29
The position verdict in this document is retired. Under the current framework (
references/criteria.md, 2026-07-29) the memo outputs an analysis, not a position. Whether an analysis justifies a position is a question about a particular book, and two books answer it differently.The Gate block and the Gate 4 expected-return arithmetic below are also superseded, by the named Criteria (each with a type: BINDING or MEASURED, returning PASS / FAIL / INDETERMINATE), the reverse-DCF implied-path test, and a separate 12-month target.
→ Current analysis:
BLLN_Criteria_and_Valuation_2026-07-29.mdEverything else here — the research, the evidence, the mechanism work — stands. Residual references to "Watchlist" in the prose below are the historical record of the 2026-07-28 assessment and are left intact deliberately.
RESOLVED IDENTITY — verified before any analysis. BLLN is BillionToOne, Inc., CIK 0002070849, Nasdaq Global Select, SIC 8071 (Medical Laboratories), HQ Menlo Park CA. A molecular diagnostics company (cell-free DNA prenatal and oncology testing). IPO'd 2025-11-06 at $60.00. Currently listed and filing (10-K 2026-03-11; 10-Q 2026-05-06). Resolved against SEC EDGAR's official ticker file by exact match, cross-checked against 180 sessions of Alpaca SIP price bars and corroborated by web search. This is not Ballard Power [BLDP] and not Bloom Energy [BE] — both were explicitly checked and rejected.
POSITION VERDICT: RETIRED 2026-07-29 — the memo outputs an analysis, not a position.
See BLLN_Criteria_and_Valuation_2026-07-29.md for the current Criteria block.
The gate lines below are the 2026-07-28 record and are superseded.
GATES: 1 (Mechanism) PASS
2 (Variant vs Consensus) FAIL <-- BINDING GATE
3 (Catalyst) PASS
4 (Expected Return) FAIL (+0.64% vs 4.7% hurdle — but see the range)
5 (Feasibility) PASS equity / FAIL options
6 (Momentum / Tape) PASS (with the tape — at an all-time high)
SPOT $133.64 ENTRY $105.00 BASE TARGET $136.01 BEAR $74.63 BULL $203.62
E[R] AT SPOT: +0.64% | RANGE ACROSS WEIGHTINGS: -9.01% to +7.76%
>> THE 4.7% CASH HURDLE SITS *INSIDE* THAT RANGE <<
Flip point: E[R] drops below the hurdle at a 22% bear weight (house uses 30%)
Flip point on price: clears the hurdle at ~$127 and below
E[R] AT THE $105 ENTRY: +28.1%
SIZING: Conviction LOW (0.52 composite) | Volatility HIGH (85.3% realised)
0% today. 1.0% of book on conversion, 1.5% ceiling.
VEHICLE: Outright equity only — options excluded on spreads (16-32% of mid), not on direction.
One-line thesis: An genuinely excellent business — revenue tripled in two years, gross margin 24% → 73%, newly profitable, $447m net cash — trading 8.6% above the Street's average price target on a price that requires it to build a multi-billion-dollar oncology franchise from $42.9m of annualised revenue, one peer-reviewed publication and no registered MRD trial.
This memo does not claim an edge on the near-term numbers, and says so up front. The house Base case for FY2026 revenue is $462m against consensus of $454m — a variant of +1.8%; FY2027 is +4.2%. Company guidance is $450–465m. I agree with the Street to within two percent. Gate 2A therefore fails on magnitude, and no amount of valuation work can substitute for that.
What follows is consequently framed as why this is not yet ownable, not as why the market is wrong.
| $m | FY2023A | FY2024A | FY2025A | Q1-2026A |
|---|---|---|---|---|
| Revenue | 71.7 | 152.6 | 305.1 | 108.4 |
| Gross margin | 24.1% | 53.0% | 68.3% | 73.0% |
| Operating income | (69.5) | (47.1) | 16.0 | 17.8 |
| Cash from operations | (53.7) | (41.4) | 24.6 | 15.4 |
Every line tied back to the filed FY2025 10-K and Q1-2026 10-Q. The Excel model reproduces all six FY2025 lines with a difference of exactly 0.00 — revenue, gross profit, R&D, SG&A, operating income and net income. The balance sheet balances to 0.00 in all three periods. Per the standing rule, a zero balance check proves internal consistency only, which is why the separate tie-out block exists.
The mechanism is specific and disclosed: payor in-network conversion. Contracted lives went from >250m (FY2025 10-K) to ~300m — over 90% of the US population — after the Anthem contract. That drove ASP +28% YoY to $571 while COGS per test fell to $153. Volume grew 44%. UNITY now touches roughly 1 in 11 US pregnancies.
The factor scorecard agrees: negative accruals (−1.14% TTM), top-decile gross profitability (GP/TA 0.356), F-score 7/8, estimate revisions +12% since March, and a close at the all-time high. Six of eight computable factors are tailwinds for the long side. Not one of them supports a short.
The revenue note discloses revenue recognised for performance obligations satisfied in prior periods — retroactive re-pricing of old claims when new payor deals are signed:
FY2023 $2.7m · FY2024 $11.0m · FY2025 $8.7m · Q1-2026 alone $9.2m
One quarter exceeded the entire prior year, and equalled 8.5% of the quarter's revenue. Stripping it:
| Reported | Organic | |
|---|---|---|
| Q1-26 sequential | +12.8% | +5.4% |
| Q1-26 YoY | +83.8% | +76.9% |
Against organic sequential growth of +15% to +26% through 2025, this is a sharp deceleration — and the FY2026 guide requires organic sequential growth of roughly 8–10% for the balance of the year. The quarterly allocation of FY2025's true-up is an assumption; under every plausible allocation the sequential figure lands between +3.3% and +9.9%, so the deceleration is robust even though the precise number is not.
This is not an accounting abuse — the disclosure is clear and voluntary at note level, the cash is genuinely owed, and management confirmed no further true-up is embedded in guidance. But it flattered the optics of the quarter that took the stock to its high.
A reverse DCF at $133.64 (WACC 11.45%, terminal margin 27%, 4.5x exit) requires FY2035 revenue of ~$3,515m — 11.5x FY2025. In units: at a ~$600 mature ASP that is roughly 5.9m billable tests a year against 610,000 delivered in FY2025, a 9.6x volume increase.
Bottom-up, the US prenatal SAM tops out near $735–850m even granting 25% share of an 80%-penetrated market. So the current price requires oncology to become roughly three-quarters of the company.
Oncology today: $10.7m in Q1-2026 ($42.9m annualised). One PubMed publication for Northstar Select against 151 for Natera's Signatera. Three registered clinical trials, of which zero are MRD studies (the two oncology trials enrol 50 and 20 patients). No Medicare coverage for Northstar Response. The tumour-naive MRD test is guided to launch by end-2026 with validation data "published concurrently at launch rather than beforehand."
I opened the ClinicalTrials.gov and PubMed records and read the fields rather than citing them second-hand. The one piece of hard, filed, independent evidence pointing the other way is genuine and belongs in the record: the 2026-06-23 8-K lease for 62,659 sq ft in Union City on a 12-year term, more than tripling oncology-dedicated laboratory space. That is a real capital commitment. It is not enough to substitute for a clinical evidence base.
The FY2025 10-K discloses material weaknesses that remain unremediated: an under-resourced control environment with inadequate segregation of duties; controls over certain financial instruments; and IT general controls over journal entries. They do not name revenue recognition — which limits how much weight this can carry, and I would rather say that than overstate it. But revenue here is unusually estimate-dependent (variable consideration, expected-value method, hindsight adjustment) and the true-up line is accelerating. A real yellow flag that does not currently reach the load-bearing number.
DCF says expensive. Base case $53.35 (Gordon) to $79.90 (4.5x exit sales) versus $133.64. The sensitivity grid reaches spot only at roughly a 6.0x terminal sales multiple with a sub-10% WACC.
Comps say the opposite. At 10.8x EV/FY2027E sales, BLLN is cheaper than NTRA (~11.9x) and GH (~14.4x) while growing about three times as fast with better margins, and it sits below the peer growth-adjusted regression line.
These two conflict, and the memo does not resolve the conflict by choosing the convenient one. The DCF's terminal assumptions do heavy lifting: 4.5x exit sales on a 75%-gross-margin franchise is roughly 16.7x terminal EBIT, which is arguably harsh for high-quality diagnostics. Equally, the comp set may simply be expensive together — a sector-regime question, not a stock-specific edge. The honest statement is that reasonable analysts land between "40% overvalued" and "fairly valued," and that the decision therefore turns on the terminal multiple rather than on any insight about the business.
A correction made during the build, recorded because it changed the answer. The measured beta over 180 post-IPO sessions is 1.75 — but decomposed, β = ρ × (σ_BLLN/σ_SPY) = 0.272 × (85.3/13.3). The entire figure is BLLN's own idiosyncratic volatility scaled by a market correlation of just 0.27. CAPM does not compensate diversifiable risk, and 180 sessions is far too short. The house uses a peer-informed β of 1.35 (WACC 11.45%). Had the measured beta been used uncritically, fair value would have printed ~$42 and the memo would have looked far more confident than the evidence permits.
references/trade-construction.md requires this to be stated whenever it applies. It applies here.
The entire bear case is the multiple. Against that: the house forecast is above consensus; the factor scorecard is clean in every dimension a short thesis would need to be dirty (negative accruals, top-decile gross profitability, F-score 7/8); the balance sheet carries $447m of net cash and no refinancing risk; and the stock closed at its all-time high on the day of this memo. Shorting would mean fighting the tape at its most extreme with no catalyst capable of breaking it inside the horizon, while arguing directly against the name's own quantitative evidence. Expensive is not a short.
Gate 2 fails on evidence. There is no near-term variant (+1.8%), and the duration variant fails leg 1 — one publication, zero registered MRD trials. The stock trades 8.6% above the Street's $122.14 average target. E[R] at spot is +0.64% against a 4.7% cash hurdle. Paying up for optionality that is not yet underwritable is the mistake this framework exists to prevent.
E[R] = +0.64%; range across plausible weightings −9.01% to +7.76%; the 4.7% hurdle sits INSIDE the range.
Per framework item C4, the honest statement is that this decision is not determined by the analysis — it is determined by a judgement input. The flip point is a 22% bear weight against the 30% used; an analyst using 20% would pass this gate. On price it clears at ~$127, only 5% below spot.
This is a far closer call than the recent healthcare comparables — TXG and TWST failed by roughly 50pp even at a zero bear weight. That distinction matters for calibration and is logged.
Convert to Long at $105.00 (E[R] +28.1% — real margin over the hurdle, not the ~5% sliver at $127).
Or, price-independent, if all three complete: (i) tumour-naive MRD launches on time with peer-reviewed validation data, (ii) Northstar Response secures MolDX/Medicare coverage, (iii) a health-system contract is quantified in guidance. That would satisfy Gate 2B leg 1 and convert narrative into evidence.
Move to Avoid if: organic sequential growth prints below +4% for two consecutive quarters; or FY2026 guidance is cut; or ICFR weaknesses remain unremediated at the FY2026 10-K; or MRD slips beyond H1-2027.
Book is 100% cash, zero positions, 13 watchlist names. BLLN's maximum correlation to any coverage name is +0.356 (TWST); it correlates only +0.338 with Natera despite being a direct prenatal competitor and +0.261 with Guardant. No pair approaches the 0.60 disclosure threshold. BLLN would open a genuinely idiosyncratic sleeve rather than double an existing bet — it is the least correlated healthcare name in coverage.
Capital-competition test: E[R] +0.64% at spot loses to cash at 4.7%. Cash wins. No position today.
Sources: SEC EDGAR (CIK 0002070849) — FY2025 10-K, Q1-2026 10-Q, 8-K EX-99.1 earnings releases, 39 Form 4 XML filings; Alpaca Markets SIP equity and options data; ClinicalTrials.gov API; NCBI PubMed E-utilities; stockanalysis.com and MarketBeat for consensus and short interest. Alpha Vantage was exhausted for the day and was not used. Every estimate and assumption is flagged inline.