Castle Biosciences share price today

Castle Biosciences, Inc.'s share price was $35.75 at the close on 4 November 2026. That is 25.7% above its average price over the last 200 trading days. In the last 52 weeks it traded between $19 and $42, and at that close it sat 72% of the way up from that low.

A share price tends to move through four phases: moving sideways (stage 1), rising (stage 2), stalling near a high (stage 3) and falling (stage 4). The phase helps read everything below.

Over the past 13 weeks it has done better than the S&P 500, and it has stayed ahead for 15 weeks in a row.

Over the last 1 year the share price moved +82% while the S&P 500 moved +23%, so it is ahead of the index over that whole period. The chart above shows the 13-week comparison for every week.

This page treats a rise as over when the price closes below its 200-day average on two Fridays in a row.

Castle Biosciences, Inc. pays no dividend. In the last 12 reported quarters it declared no dividend per share, so there is no payout history to chart and no yield to show. Companies like this usually keep their earnings in the business, so the cash-flow sections show where that cash goes.

Castle Biosciences is not in the Nasdaq 100, the S&P 500 or the Dow Jones 30, and is not on the US tech stocks list.

Castle Biosciences, Inc. posted a net loss of $2.1 M in the Jun 2026 quarter. The full FY25 year was a loss of $24.2 M. That loss is 2.0% of the quarter's revenue. The same quarter a year earlier earned $4.5 M. 8 of the last 12 reported quarters were loss-making.

Net profit is what is left after every cost, interest and tax. Earnings per share, dividends and book value all grow from it.

Jun 2026 profit was −$2.1 M, −145.5% on a year earlier. For the full year, FY25 profit was −$24.2 M (−232.4% on the year before).

Why profit moved: revenue changed +20.1% on a year earlier and the margin moved +1.9 percentage points. Sales did the work, and the margin was about flat.

On average over the last four quarters, profit changed −130.6% and revenue +3.2%. Profit is growing slower than sales: rising costs are taking part of the growth.

Castle Biosciences, Inc. reported $104 M of revenue in the Jun 2026 quarter, +20.1% on the same quarter a year earlier. Over 4 years it has grown 38.3% a year on average. The last full year, FY25, came in at $344 M. The last four reported quarters add to $357 M.

Revenue is everything the company billed its customers in the period.

FY25 revenue was $344 M, +3.7% on the year before.

Recent pace: the last four quarters grew +3.2% on average, against 38.3% a year over the longer run, so this year is growing slower than its own long-run rate.

Is growth speeding up? Revenue over the last 12 months grew +3.2%, against +11.5% a year over the last 8 quarters (rolling over).

Castle Biosciences, Inc.'s operating margin was −3.0% in the Jun 2026 quarter, 1.9 percentage points higher than the same quarter a year ago. Across 5 years it has been between −66.5% and 2.6%. The latest quarter is within that range.

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

Why the margin moved: operating margin changed +1.9 percentage points on the year while gross margin changed −2.4 points. So the gain came mostly from the gross margin, which means input costs and prices charged.

Castle Biosciences, Inc.'s cash-flow history is too short to judge how much of its profit turns into cash. In FY25 it brought in $64.3 M of operating cash against −$24.2 M of profit. After $36.0 M of spending on assets, $28.3 M was left over as free cash.

The profit and loss account shows what was earned. The cash-flow statement shows the cash that actually came in. Comparing operating cash flow with profit is one of the best checks that a profit is real.

Cash-flow figures here are yearly, because quarterly cash statements are not published, so this section changes once a year.

What to look at next: the main use of cash is spending on assets. The next section checks what that spending is building.

Castle Biosciences, Inc. does not report the customer, stock and supplier day counts a cash cycle needs, so this section looks at its spending on assets instead. It spent $78.0 M on assets over the last 3 years. Averaged over those years that is 7.6% of FY25 revenue a year.

Working capital is the cash tied up between paying suppliers and getting paid. Debtor days: how long customers take to pay. Inventory days: how long stock sits. The cash cycle: the whole loop, in days of sales.

Nothing is estimated in place of the missing day counts, so no cash-cycle chart is drawn.

Spending on assets: $78.0 M over the last 3 years.

In short: the cash is going into new capacity, not getting stuck in the daily cycle. The question is whether the new capacity earns.

Castle Biosciences, Inc. has no P/E right now, because its earnings are negative. The revenue and margin sections are where a turn would show first. Measured against sales instead, the market values Castle Biosciences, Inc. at 3.2× its FY25 revenue of $344 M. The P/E comes back here once profit turns positive.

P/E is the share price divided by a year's profit per share: how many dollars the market pays for each dollar of yearly profit.

Why the multiple is where it is: over the past year earnings per share moved −234.4% while the price moved +8.2%. The price did better than earnings, which pushed the multiple up within its own range.

Castle Biosciences, Inc.'s business trend cannot be read yet. There are fewer than eight usable quarters of growth figures, so there is not enough history to read the trend. This is based on 12 quarters of 2 measures, with some gaps.

Every business is somewhere on a path of getting better or worse, and this section names where. The last 12 quarters of growth in revenue, profit and earnings per share, plus the return the business earns on its capital, are read as lines. Getting worse: the lines are falling. Turning around: a low point has just formed and the last few quarters are rising from it. Getting better: the rise from the low has lasted. Growing steadily: steady growth with healthy returns. Slowing from a peak: still high, but slowing. When the lines disagree the result is mixed; too little history means no reading. CAGR (compound annual growth rate) is the steady yearly rate that would turn the starting value into the latest one. It is the fairest way to compare growth over different periods. If the 1-year figure is much bigger than the 10-year one, recent growth is running faster than the long-run trend. A dash means there is no figure for that period, or the starting year was a loss, where a growth rate means nothing.

Why it matters: with too little history, we say so rather than guess a direction.

One or more growth lines have an extreme jump caused by comparing with a near-zero or loss-making quarter. Those jumps are capped before reading and drawn at the edge of the chart, so one odd quarter does not decide the result.

There are fewer than eight usable quarters, so this page does not guess a direction from so little history.

Compound annual growth rate (%)

Compound annual growth rate over each period, %. Revenue, profit and EPS come from yearly figures; the stock price row is price growth over the same periods. A dash means no figure for that period, or the starting year was a loss.

Castle Biosciences, Inc. earned a ROE of −5% in FY25. That is up from a low of −17% in FY22. Its return on capital used (ROIC) is 14.2 percentage points below its cost of capital, so growth here does not yet pay for the capital it uses.

Return on equity (ROE) is the profit the business earns on its shareholders’ money. We do not have the full capital split, so ROE is the longest history we can draw here.

It comes from a −7.0% net margin and 0.59× asset turnover (sales divided by assets).

Why the return is what it is (FY25): a −7.0% net margin × 0.59× asset turnover × 1.23× leverage (assets divided by equity) ≈ −5.1% on equity. The margin does its share; borrowing plays a small part, so this return is earned, not borrowed.

The key test, return on capital used minus the cost of capital: −5.0% − 9.2% = −14.2 percentage points. The 9.2% is an estimate of this company's own cost of capital. Read the sign and size of the gap, not the decimals. Negative: growth at these returns loses value until returns improve.

The −5.0% ROIC above is the latest reading, as reported. The yearly chart below shows FY25 at −11.4%, and the quarterly chart works out each 12-month window from the quarterly figures, so the readings differ by date, not by method.

Castle Biosciences, Inc. has total debt of $36.6 M against shareholder equity of $470 M as of Jun 2026, so its debt is 0.08× its equity, which is very little. Year by year, that ratio went from 0.02 in FY21 to 0.08 in FY25. So the returns on this page come from the business, not from borrowed money.

Debt-to-equity shows how much of the business is paid for with borrowed money. Lower is safer, and the direction matters as much as the level.

7.4% of Castle Biosciences, Inc.'s tradable shares are in short positions, which are bets that the price will fall, so some traders are betting against it. At normal trading volumes, closing those positions would take about 5.2 days. US companies do not publish a quarter-by-quarter list of owners, so this page uses short interest instead.

There is no quarter-by-quarter list of owners here, so we look at short interest: the share of tradable shares held in short positions, which gain if the price falls.

It is a single reading at one point in time; we do not have its history.

Why it is at this level: the figure does not say who has the short positions or why, so we show the level without guessing the story.

For Castle Biosciences, Inc., the Z-score is 5.77. A Z-score above about 3 is safe and below about 1.8 signals danger, so this is well clear of danger. It estimates how far the balance sheet is from trouble; it is not a forecast of failure.

The Z-score estimates how far a company is from balance-sheet trouble. Above about 3 is safe; below about 1.8 is the danger zone. It was built for manufacturers, so it is not used for banks and lenders.

Why it matters: a Z-score of 5.77 is well clear of the danger zone, so the balance sheet is not the risk here.

35.4 out of 100, rank 28 of 30 in Diagnostics & Research, with 64% of the evidence available.

Castle Biosciences, Inc. scores 35.4 out of 100 against the 30 companies it is compared with in Diagnostics & Research, ranking 28. The evidence is balanced: no factor stands out, so another reported quarter is needed before the picture is clearer.

The four parts add up to the total exactly: 12.7 + 6.6 + 11.2 + 4.9 = 35.4. This is the same number shown on the industry page; it is worked out once for the whole group and read here.

What would change it: The score would fall if profit growth turns negative or margins stop improving while the share price lags its sector.

Castle Biosciences ranks 28 of 30 Diagnostics & Research companies on the 4-Factor Sector Score, with 35.4 out of 100.

Missing figures are not scored as bad. They lower the confidence and pull the final score toward the middle. Relative strength counts only when the company has a reading for this week; with no reading, that factor is left out and its 20 points are shared across the other three in proportion. PEG is not shown when the ratio cannot mean anything: the company must be making a profit, its price-to-earnings must be positive, and its three-year earnings growth must fall between 5% and 60%. Dividing a price multiple by a loss, or by growth measured off a tiny base, produces a number that looks precise and tells you nothing. Under relative strength, one mark per week shows the last 12 weeks: a mark is filled where the company led S&P 500 by 5% or more over the 13 weeks ending that week, which is the same test used everywhere on this site. Price stage places the company on the same six-step path the industry is placed on (basing, turning, breaking out, leader, fading, asleep), read from how many weeks running it has led S&P 500 and whether that lead is growing or shrinking. It describes where the share price stands, not the direction of earnings, and it is not a recommendation; it is left blank for a company whose weekly history is too short or too stale to read.

The figures in this ranking come from the industry comparison: results through the Sep 2026 quarter, and the P/E at that quarter's end. The sections above use the latest weekly price, so a P/E or return there can differ a little from the one here. The stage words in this ranking (such as losing its lead or breaking out) describe the lead over the index, not the price phase in the price section.

Related companies: Diagnostics & Research, all 30 compared on one page.

Castle Biosciences is the 30th largest of 34 Diagnostics & Research companies on Sector Alpha by market value (scores of 4 November 2026). Just above it: GeneDx Holdings Corp., Personalis, Inc. and OPKO Health, Inc. Just below it: Myriad Genetics, Inc., Fulgent Genetics, Inc. and Biodesix, Inc.

Diagnostics & Research companies close in size

27. GeneDx Holdings Corp. $2.1 billion
28. Personalis, Inc. $1.7 billion
29. OPKO Health, Inc. $1.3 billion
30. Castle Biosciences, Inc. $1.1 billion
31. Myriad Genetics, Inc. $576 million
32. Fulgent Genetics, Inc. $542 million
33. Biodesix, Inc. $227 million

All 34 Diagnostics & Research companies, largest first

Companies close in size in other industries

2377. IRSA Inversiones y Representaciones Sociedad Anónima $1.1 billion · Real Estate Services
2378. Horizon Bancorp, Inc. $1.1 billion · Banks - Regional
2379. Castle Biosciences, Inc. $1.1 billion
2380. Ecovyst Inc. $1.1 billion · Specialty Chemicals
2381. EverQuote, Inc. $1.1 billion · Internet Content & Information

Sector Alpha, written by code from the published numbers. Data as of 4 November 2026.

Every chart on this page is drawn by code from the published figures, with no forecasts and no price opinions.

See the plain-text version of this page.