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 PS Business Parks, Inc. (NYSE:PSB).

PS Business Parks has a ROE of 9.8%, based on the last twelve months. That means that for every $1 worth of shareholders' equity, it generated $0.10 in profit.

See our latest analysis for PS Business Parks

How Do You Calculate ROE?

The formula for return on equity is:

Return on Equity = Net Profit ÷ Shareholders' Equity

Or for PS Business Parks:

9.8% = US$112m ÷ US$2.0b (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 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 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. That means that the higher the ROE, the more profitable the company is. So, all else being equal, a high ROE is better than a low one. That means it can be interesting to compare the ROE of different companies.

Does PS Business Parks 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. Pleasingly, PS Business Parks has a superior ROE than the average (6.1%) company in the REITs industry.

That is a good sign. We think a high ROE, alone, is usually enough to justify further research into a company. For example, I often check if insiders have been buying shares.

How Does Debt Impact ROE?

Most companies need money -- from somewhere -- to grow their profits. The cash for investment can come from prior year profits (retained earnings), issuing new shares, or borrowing. In the case of the first and second options, the ROE will reflect this use of cash, for growth. In the latter case, the debt required for growth will boost returns, but will not impact the shareholders' equity. In this manner the use of debt will boost ROE, even though the core economics of the business stay the same.

Combining PS Business Parks's Debt And Its 9.8% Return On Equity

Shareholders will be pleased to learn that PS Business Parks has not one iota of net debt! Even though I don't think its ROE is that great, I think it's very respectable when you consider it has no debt. At the end of the day, when a company has zero debt, it is in a better position to take future growth opportunities.

In Summary

Return on equity is a useful indicator of the ability of a business to generate profits and return them to shareholders. 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 ROE is just one piece of a bigger puzzle, since high quality businesses often trade on high multiples of earnings. 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 I think it may be worth checking this free report on analyst 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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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.