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. To keep the lesson grounded in practicality, we'll use ROE to better understand CarMax, Inc. (NYSE:KMX).

ROE or return on equity is a useful tool to assess how effectively a company can generate returns on the investment it received from its shareholders. In other words, it is a profitability ratio which measures the rate of return on the capital provided by the company's shareholders.

How Do You Calculate Return On Equity?

The formula for ROE is:

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

So, based on the above formula, the ROE for CarMax is:

6.8% = US$418m ÷ US$6.2b (Based on the trailing twelve months to August 2024).

The 'return' is the yearly profit. So, this means that for every $1 of its shareholder's investments, the company generates a profit of $0.07.

Does CarMax Have A Good Return On Equity?

Arguably the easiest way to assess company's ROE is to compare it with the average in its industry. Importantly, this is far from a perfect measure, because companies differ significantly within the same industry classification. As shown in the graphic below, CarMax has a lower ROE than the average (19%) in the Specialty Retail industry classification.

That certainly isn't ideal. That being said, a low ROE is not always a bad thing, especially if the company has low leverage as this still leaves room for improvement if the company were to take on more debt. When a company has low ROE but high debt levels, we would be cautious as the risk involved is too high.

The Importance Of Debt To Return On Equity

Companies usually need to invest money to grow their profits. That cash can come from issuing shares, retained earnings, 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.

CarMax's Debt And Its 6.8% ROE

It's worth noting the high use of debt by CarMax, leading to its debt to equity ratio of 2.94. With a fairly low ROE, and significant use of debt, it's hard to get excited about this business at the moment. Debt does bring extra risk, so it's only really worthwhile when a company generates some decent returns from it.

Summary

Return on equity is useful for comparing the quality of different businesses. A company that can achieve a high return on equity without debt could be considered a high quality business. All else being equal, a higher ROE is better.

Having said that, while ROE is a useful indicator of business quality, you'll have to look at a whole range of factors to determine the right price to buy a stock. Profit growth rates, versus the expectations reflected in the price of the stock, are a particularly important to consider. So you might want to take a peek at this data-rich interactive graph of forecasts for the company.

Of course, you might find a fantastic investment by looking elsewhere. So take a peek at this free list of interesting companies.

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This article by Simply Wall St is general in nature. We provide commentary based on historical data and analyst forecasts only using an unbiased methodology and our articles are not intended to be financial advice. It does not constitute a recommendation to buy or sell any stock, and does not take account of your objectives, or your financial situation. We aim to bring you long-term focused analysis driven by fundamental data. Note that our analysis may not factor in the latest price-sensitive company announcements or qualitative material. Simply Wall St has no position in any stocks mentioned.