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 Ozner Water International Holding Limited (HKG:2014), by way of a worked example.

Over the last twelve months Ozner Water International Holding has recorded a ROE of 4.3%. Another way to think of that is that for every HK$1 worth of equity in the company, it was able to earn HK$0.04.

See our latest analysis for Ozner Water International Holding

How Do I Calculate ROE?

The formula for ROE is:

Return on Equity = Net Profit ÷ Shareholders' Equity

Or for Ozner Water International Holding:

4.3% = CN¥129m ÷ CN¥3.4b (Based on the trailing twelve months to June 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. 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 measures a company's profitability against the profit it retains, and any outside investments. The 'return' is the yearly profit. The higher the ROE, the more profit the company is making. So, as a general rule, a high ROE is a good thing. Clearly, then, one can use ROE to compare different companies.

Does Ozner Water International Holding Have A Good ROE?

By comparing a company's ROE with its industry average, we can get a quick measure of how good it is. The limitation of this approach is that some companies are quite different from others, even within the same industry classification. If you look at the image below, you can see Ozner Water International Holding has a lower ROE than the average (10.0%) in the Consumer Durables industry classification.

That certainly isn't ideal. We prefer it when the ROE of a company is above the industry average, but it's not the be-all and end-all if it is lower. Still, shareholders might want to check if insiders have been selling.

How Does Debt Impact Return On Equity?

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 case of the first and second options, the ROE will reflect this use of cash, for growth. In the latter case, the use of debt will improve the returns, but will not change the equity. In this manner the use of debt will boost ROE, even though the core economics of the business stay the same.

Ozner Water International Holding's Debt And Its 4.3% ROE

While Ozner Water International Holding does have some debt, with debt to equity of just 0.60, 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. Careful use of debt to boost returns is often very good for shareholders. However, it could reduce the company's ability to take advantage of future opportunities.

The Bottom Line On ROE

Return on equity is useful for comparing the quality of different businesses. Companies that can achieve high returns on equity without too much debt are generally of good quality. 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. It is important to consider other factors, such as future profit growth -- and how much investment is required going forward. So you might want to check this FREE visualization of analyst forecasts for the company.

Of course Ozner Water International Holding 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.

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.

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. Thank you for reading.