# Is Castle Biosciences, Inc.’s (NASDAQ:CSTL) ROE Of 8.6% Concerning?

One of the best investments we can make is in our own knowledge and skill set. With that in mind, this article will work through how we can use Return On Equity (ROE) to better understand a business. We’ll use ROE to examine Castle Biosciences, Inc. (NASDAQ:CSTL), by way of a worked example.

Our data shows Castle Biosciences has a return on equity of 8.6% for the last year. That means that for every \$1 worth of shareholders’ equity, it generated \$0.09 in profit.

Check out our latest analysis for Castle Biosciences

### How Do You Calculate ROE?

The formula for ROE is:

Return on Equity = Net Profit (from continuing operations) ÷ Shareholders’ Equity

Or for Castle Biosciences:

8.6% = US\$7.1m ÷ US\$82m (Based on the trailing twelve months to September 2019.)

It’s easy to understand the ‘net profit’ part of that equation, but ‘shareholders’ equity’ requires further explanation. It is all the money paid into the company from shareholders, plus any earnings retained. Shareholders’ equity can be calculated by subtracting the total liabilities of the company from the total assets of the company.

### What Does ROE Mean?

Return on Equity measures a company’s profitability against the profit it has kept for the business (plus any capital injections). The ‘return’ is the amount earned after tax over the last twelve months. The higher the ROE, the more profit the company is making. So, all else equal, investors should like a high ROE. That means ROE can be used to compare two businesses.

### Does Castle Biosciences Have A Good Return On Equity?

By comparing a company’s ROE with its industry average, we can get a quick measure of how good it is. However, this method is only useful as a rough check, because companies do differ quite a bit within the same industry classification. As shown in the graphic below, Castle Biosciences has a lower ROE than the average (20%) in the Biotechs industry classification.

Unfortunately, that’s sub-optimal. It is better when the ROE is above industry average, but a low one doesn’t necessarily mean the business is overpriced. Still, shareholders might want to check if insiders have been selling.

### How Does Debt Impact ROE?

Virtually all companies need money to invest in the business, to grow profits. That cash can come from retained earnings, issuing new shares (equity), or debt. In the first and second cases, the ROE will reflect this use of cash for investment in the business. In the latter case, the debt used for growth will improve returns, but won’t affect the total equity. That will make the ROE look better than if no debt was used.

### Combining Castle Biosciences’s Debt And Its 8.6% Return On Equity

While Castle Biosciences does have some debt, with debt to equity of just 0.30, we wouldn’t say debt is excessive. Its ROE isn’t particularly impressive, but the debt levels are quite modest, so the business probably has some real potential. Conservative use of debt to boost returns is usually a good move for shareholders, though it does leave the company more exposed to interest rate rises.

### The Bottom Line On ROE

Return on equity is one way we can compare the business quality of different companies. In my book the highest quality companies have high return on equity, despite low debt. If two companies have the same ROE, then I would generally prefer the one with less debt.

But when a business is high quality, the market often bids it up to a price that reflects this. The rate at which profits are likely to grow, relative to the expectations of profit growth reflected in the current price, must be considered, too. So you might want to check this FREE visualization of analyst forecasts for the company.

Of course Castle Biosciences may not be the best stock to buy. So you may wish to see this free collection of other companies that have high ROE and low debt.

If you spot an error that warrants correction, please contact the editor at editorial-team@simplywallst.com. This article by Simply Wall St is general in nature. It does not constitute a recommendation to buy or sell any stock, and does not take account of your objectives, or your financial situation. Simply Wall St has no position in the stocks mentioned.

We aim to bring you long-term focused research analysis driven by fundamental data. Note that our analysis may not factor in the latest price-sensitive company announcements or qualitative material. Thank you for reading.