While some investors are already well versed in financial metrics (hat tip), this article is for those who would like to learn about Return On Equity (ROE) and why it is important. By way of learning-by-doing, we'll look at ROE to gain a better understanding of SDI Limited (ASX:SDI).

SDI has a ROE of 10%, based on the last twelve months. That means that for every A$1 worth of shareholders' equity, it generated A$0.10 in profit.

Check out our latest analysis for SDI

How Do You Calculate ROE?

The formula for ROE is:

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

Or for SDI:

10% = AU$7.3m ÷ AU$73m (Based on the trailing twelve months to June 2019.)

Most readers would understand what net profit is, but it’s worth explaining the concept of shareholders’ equity. It is all earnings retained by the company, plus any capital paid in by shareholders. The easiest way to calculate shareholders' equity is to subtract the company's total liabilities from the total assets.

What Does Return On Equity Signify?

ROE looks at the amount a company earns relative to the money it has kept within the business. The 'return' is the profit over the last twelve months. A higher profit will lead to a higher ROE. So, as a general rule, a high ROE is a good thing. That means ROE can be used to compare two businesses.

Does SDI Have A Good ROE?

Arguably the easiest way to assess company's ROE is to compare it with the average in its industry. The limitation of this approach is that some companies are quite different from others, even within the same industry classification. You can see in the graphic below that SDI has an ROE that is fairly close to the average for the Medical Equipment industry (12%).

That's not overly surprising. ROE doesn't tell us if the share price is low, but it can inform us to the nature of the business. For those looking for a bargain, other factors may be more important. For those who like to find winning investments this free list of growing companies with recent insider purchasing, could be just the ticket.

The Importance Of Debt To Return On Equity

Virtually all companies need money to invest in the business, to grow profits. The cash for investment can come from prior year profits (retained earnings), issuing new shares, or borrowing. In the first two cases, the ROE will capture this use of capital to grow. In the latter case, the use of debt will improve the returns, but will not change the equity. That will make the ROE look better than if no debt was used.

Combining SDI's Debt And Its 10% Return On Equity

Shareholders will be pleased to learn that SDI has not one iota of net debt! Its respectable ROE suggests it is a business worth watching, but it's even better the company achieved this without leverage. At the end of the day, when a company has zero debt, it is in a better position to take future growth opportunities.

But It's Just One Metric

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. If two companies have the same ROE, then I would generally prefer the one with less debt.

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. It is important to consider other factors, such as future profit growth -- and how much investment is required going forward. So I think it may be worth checking this free this detailed graph of past earnings, revenue and cash flow.

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

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.