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Is Auckland International Airport Limited's (NZSE:AIA) 11% ROE Better Than Average?

Simply Wall St

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 Auckland International Airport Limited (NZSE:AIA).

Our data shows Auckland International Airport has a return on equity of 11% for the last year. Another way to think of that is that for every NZ$1 worth of equity in the company, it was able to earn NZ$0.11.

View our latest analysis for Auckland International Airport

How Do You Calculate Return On Equity?

The formula for return on equity is:

Return on Equity = Net Profit ÷ Shareholders' Equity

Or for Auckland International Airport:

11% = NZ$631m ÷ NZ$5.7b (Based on the trailing twelve months to December 2018.)

Most know that net profit is the total earnings after all expenses, but the concept of shareholders' equity is a little more complicated. 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 ROE Signify?

ROE looks at the amount a company earns relative to the money it has kept within the business. The 'return' is the amount earned after tax 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. Clearly, then, one can use ROE to compare different companies.

Does Auckland International Airport 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. Pleasingly, Auckland International Airport has a superior ROE than the average (8.3%) company in the Infrastructure industry.

NZSE:AIA Past Revenue and Net Income, August 6th 2019

That is a good sign. We think a high ROE, alone, is usually enough to justify further research into a company. One data point to check is if insiders have bought shares recently.

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 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. Thus the use of debt can improve ROE, albeit along with extra risk in the case of stormy weather, metaphorically speaking.

Auckland International Airport's Debt And Its 11% ROE

While Auckland International Airport does have some debt, with debt to equity of just 0.38, we wouldn't say debt is excessive. The fact that it achieved a fairly good ROE with only modest debt suggests the business might be worth putting on your watchlist. Judicious use of debt to improve returns can certainly be a good thing, although it does elevate risk slightly and reduce future optionality.

The Bottom Line On ROE

Return on equity is useful for comparing the quality of different businesses. In my book the highest quality companies have high return on equity, despite low debt. 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, you might find a fantastic investment by looking elsewhere. So take a peek at this free list of interesting companies.

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.