Castle Biosciences, Inc.

Price story Before the numbers, the tape. A stock price moves through four repeating seasons: a flat base (stage 1), an advance (2), a top (3), a decline (4). Where the price sits in that cycle frames everything below.

Castle Biosciences, Inc. trades at $23.9, between stages. That is −17.1% against its own 200-day average. It sits at 21% of a 52-week range of $19 to $42. On relative strength it is currently behind the S&P 500 on a trailing-13-week view (26 weeks and counting).

Today the stock is between stages. At $23.9 it trades −17.1% versus its 200-day average and sits at 21% of its 52-week range ($19–$42).

Against the market, two honest reads. Cumulative: over the last 1.0 years the stock moved +22% while the S&P 500 moved +19% — ahead of the index over the full window. Recent form: on a trailing-13-week view the stock is currently behind (26 weeks and counting; last ahead the week of 2026-01-30) — the ribbon below is that same metric, week by week.

What would end the trend, mechanically: two Friday closes in a row below the 200-day line. That is the exit rule — no debates.

→ The trend is one thing; the bill is another. Are you paying up for it? Next: how the P/E reads against its own history.

Valuation P/E is the price of $1 of annual profit: how many dollars the market pays for each dollar the company earns in a year.

P/E does not price Castle Biosciences, Inc. — earnings are negative, so there is no multiple to rank against its own history. The revenue and margin lines below are where a turn, when it comes, would show first. On sales the market values Castle Biosciences, Inc. at 2.9× its FY25 revenue of $0.3 B.

With earnings negative, P/E does not price — there is no multiple to rank against its own history. The revenue and margin lines below are where the turn, when it comes, will show first.

🚨 Why the multiple sits where it does: over the past year annual EPS moved −233.9% against a +48.7% price move — the price outran earnings, pushing the multiple UP its own range.

Put together: the multiple is unremarkable against its own past, so the story rests on the earnings line underneath it, not the multiple.

→ Cheap or dear rides on the earnings. Are they actually growing? Next: the fundamental stage — where the business sits in its arc, and how growth has compounded.

Stage: No read Every business sits somewhere on a fundamental arc, and this page names the spot before anything else. The last twelve quarters of revenue, profit and EPS growth — plus the return the business earns on its capital — are read as curves: Deteriorating (the curves are falling), Turning around (a trough has just formed and the last few quarters lift off it), Improving (the climb off the trough is sustained), Consistent (steadily positive with healthy returns), Topping out (still high but decelerating from the peak). When the curves genuinely disagree the read is Mixed; too little history is No read. CAGR (compound annual growth rate) is the smooth yearly pace that turns the starting value into the latest one — the fairest way to compare growth across different time spans. Read the columns together: if the 1-year number towers over the 10-year, recent growth is running hotter than the long-run trend. A dash means that window is not held, or the base year was a loss (where a growth rate is not meaningful).

Castle Biosciences, Inc. reads as no read on its fundamental arc. Under eight usable quarters on the growth trio — not enough history for an honest trajectory read. The read is built from 12 quarters across 2 curves, on partial evidence.

Why it matters: with too little history, an honest page says so instead of guessing a trajectory.

Fewer than eight usable quarters on the growth curves — this page will not guess a trajectory from a stub of history.

→ The stage names the trajectory. Next: the revenue line that produces it, quarter by quarter.

4-Factor Sector Score

41.4/100 — rank 23 of 30 in Diagnostics & Research · 59% evidence confidence

Castle Biosciences, Inc. scores 41.4 out of 100 against the 30 companies it is compared with in Diagnostics & Research, ranking 23. Fill the missing evidence before acting; the ranking is deliberately pulled toward neutral.

The four contributions add to the total exactly: 18.7 + 10.1 + 9.3 + 3.3 = 41.4. This is the SAME number shown on the sector comparison — it is computed once, for the whole peer set, and read here.

What would change it: The read weakens if profit growth turns negative or margin improvement reverses while sector-relative strength deteriorates.

Revenue Revenue is the top line: everything the company billed its customers in the period.

Castle Biosciences, Inc. reported $0.1 B of revenue in the Mar 26 quarter, −11.1% year on year. Over 4 years it has compounded at 39.4% a year. The last full year, FY25, came in at $0.3 B. The last four reported quarters add to $0.3 B.

Castle Biosciences, Inc. reported $0.1 B of revenue in the Mar 26 quarter, −11.1% year on year. Over 4 years it has compounded at 39.4% a year. The last full year, FY25, came in at $0.3 B. The last four reported quarters add to $0.3 B.

FY25 revenue came in at $0.3 B (+3.0% on the year), capping 4 years at 39.4% compound. The latest quarter (Mar 26) printed $0.1 B, −11.1% year on year.

Pace check: the last four quarters averaged −5.5% growth against the decade's 39.4% — the current year is running slower than its own long-run rate.

Acceleration check: trailing-twelve-month revenue grew −5.6% over the last 4 quarters against +16.6%/yr over the last 8 — rolling over.

→ Revenue slipped — did margins hold as it scaled? Next: −25.0% this quarter (+8.3 pp YoY).

Operating margin Operating margin is what is left of every $100 of sales after running the business, before interest and tax. It is the cleanest read on pricing power and cost control.

Castle Biosciences, Inc.'s operating margin is −25.0% in the Mar 26 quarter, +8.3 percentage points against the same quarter a year ago. Across 5 fiscal years the operating margin has ranged −50.0% to 3.0%. The current quarter sits inside that band.

Castle Biosciences, Inc.'s operating margin is −25.0% in the Mar 26 quarter, +8.3 percentage points against the same quarter a year ago. Across 5 fiscal years the operating margin has ranged −50.0% to 3.0%. The current quarter sits inside that band.

The latest quarter's operating margin is −25.0%, +8.3 pp against the same quarter a year ago. Across 5 fiscal years the operating margin has ranged −50.0%–3.0%.

Why the margin moved: operating margin went +8.3 pp year on year while gross margin went −2.8 pp — the gain came mostly below the gross line: operating leverage, with costs spread over a bigger revenue base.

→ Margins held — did that reach the bottom line? Next: profit null in the latest quarter.

Net profit Net profit is what survives every cost, interest and tax — the number EPS, dividends and book value all grow from.

Castle Biosciences, Inc. posted a net loss of $0.01 B in the Mar 26 quarter. The full FY25 year was a loss of $0.02 B. That loss is 12.5% of the quarter's revenue. The same quarter a year earlier lost $0.03 B. 4 of the last 12 reported quarters were loss-making.

Castle Biosciences, Inc. posted a net loss of $0.01 B in the Mar 26 quarter. The full FY25 year was a loss of $0.02 B. That loss is 12.5% of the quarter's revenue. The same quarter a year earlier lost $0.03 B. 4 of the last 12 reported quarters were loss-making.

Mar 26 profit was $−0.0 B, null year on year. On the full year, FY25 printed $−0.0 B (−200.0%).

→ Profit rose — but did the cash follow?

Cash flow — the router The P&L says what was earned; the cash-flow statement says what actually arrived. Operating cash flow (CFO) against profit is the cleanest lie detector in the accounts.

Castle Biosciences, Inc.'s cash-flow history is too thin to judge how much reported profit converts into cash. In FY25 that was $0.1 B of operating cash against $−0.0 B of profit. After $0.0 B of capital spending, $0.0 B was left as free cash. Cash resolution here is annual, because quarterly cash statements are not published.

FY25: operating cash of $0.1 B against reported profit of $−0.0 B, leaving free cash of $0.0 B after $0.0 B of capital spending.

Cash-flow readings here are annual — that is the resolution our series carries, so this section moves once a year.

Router verdict: the visible cash user is investment — the next section checks what the spending is buying.

→ So follow the cash to where it goes. Next: $0.0 B of building over 3 years.

Where the cash goes Working capital is the cash tied up between paying suppliers and getting paid: debtor days (customers owe), inventory days (stock waits), and the cash conversion cycle (the whole loop, in days of sales).

Castle Biosciences, Inc. does not report the debtor, inventory and payable day-counts a cash cycle is built from, so this section reads the investment side instead. Capital spending ran $0.0 B over the last 3 years. Averaged over those years that is 0.0% of FY25 revenue a year.

Working-capital day-counts are not in our numbers for this stock, so this section reads the investment side — where the cash is being put to work.

On the investment side: capital spending of $0.0 B over the last 3 fiscal years.

The synthesis: the cash is going into capacity, not disappearing into the cycle — the question becomes whether the new capacity earns.

→ Does all this activity actually earn its cost of capital? Next: ROE is −3% and the ROIC − WACC spread is −24.3 pp.

Return on equity Return on equity (ROE) is the profit the business earns on its shareholders’ money. With the full capital-employed split not in our numbers, ROE is the cleanest long ladder we can draw here.

Castle Biosciences, Inc. earns a ROE of −4% in FY25. That is up from a trough of −18% in FY22. Return on invested capital clears the cost of that capital by −24.3 percentage points, so growth here is not yet paying for the capital it uses. The wiring behind it is −5.9% net margin on 0.59× asset turns.

FY25 ROE is −4%, recovered from a FY22 trough of −18% — the full ladder below shows the fall and the climb, undoctored.

🚨 Why the return is what it is — the wiring (FY25): −5.9% net margin × 0.59× asset turns × 1.23× balance-sheet leverage ≈ −4.3% on equity. Margin does its share; leverage is modest — this is an earned return, not a borrowed one.

The capstone test — ROIC − WACC: −15.0% − 9.3% = a −24.3 pp spread. The 9.3% is an estimate of this company's own cost of capital — read the sign and the size of the spread, not the decimals. Negative — growth at these returns destroys value until the returns recover.

→ Returns like these — is the balance sheet borrowing to make them? Next: debt-to-equity is 0.08.

Dividend

Castle Biosciences, Inc. pays no dividend. Across the last 12 reported quarters it has declared no dividend per share, so there is no payout history to chart and no yield to quote. Companies at this stage typically reinvest earnings rather than distribute them, which makes the cash-flow and reinvestment sections the place that cash shows up.

Castle Biosciences, Inc. does not currently pay a dividend. Across the last 12 reported quarters the company has declared no dividend per share, so there is no payout history to chart and no yield to quote. Companies at this stage typically reinvest earnings instead of distributing them.

→ No payout to follow. The cash question becomes what the business does with what it earns instead.

Debt Debt-to-equity says how much of the business is funded by borrowings. Low is the safe corner; the trend matters as much as the level.

Castle Biosciences, Inc. carries total debt of $0.0 B against shareholder equity of $0.5 B as of Mar 26, a debt-to-equity of 0.09 — effectively unlevered. On the annual view that ratio went from 0.02 in FY21 to 0.09 in FY25. The returns elsewhere on this page are therefore earned rather than borrowed.

Mar 26: total debt of $0.0 B against shareholder equity of $0.5 B — a debt-to-equity of 0.09. On the annual view, debt-to-equity went from 0.02 (FY21) to 0.09 (FY25). The returns on this page are earned, not borrowed.

→ Who owns this, and are they adding or leaving? Next: short interest is 5.3% of the float.

Ownership There is no quarter-by-quarter holder register to read here, so we read the crowd through short interest — the slice of tradable shares currently sold short, positioned for a fall.

5.3% of Castle Biosciences, Inc.'s tradable float is currently sold short — some money is positioned against it. At typical trading volumes those positions would take about 4.0 days to buy back. There is no quarter-by-quarter holder register to read for this filer, so the crowd is read through short interest instead.

The latest reading: 5.3% of the float is sold short, and at typical trading volumes it would take about 4.0 days to buy those positions back. Some money is positioned against it. This is a single point-in-time reading — we do not yet hold its history, so we show no trend chart.

Why it sits there: who is doing the shorting, and why, does not travel with the number — the level is shown without inventing its story.

→ One last check: does the safety math agree? Next: the balance-sheet safety line.

Safety line The Z-score estimates how far a company sits from balance-sheet distress — above roughly 3 is safe, below roughly 1.8 is the danger zone. It was built for manufacturers, so it is not applied to banks and lenders.

Castle Biosciences, Inc.: the Z-score reads 5.67. A Z-score above roughly 3 reads as safe and below roughly 1.8 as the distress zone, so this sits well clear of distress. It is a distance-to-distress estimate from the balance sheet, not a forecast of failure.

Why it matters: a Z-score of 5.67 sits well clear of the distress zone — the balance sheet is not the risk here.

The safety line in one sentence: the Z-score reads 5.67.

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