This article is written for those who want to get better at using price to earnings ratios (P/E ratios). We'll apply a basic P/E ratio analysis to Aéroports de Paris SA's (EPA:ADP), to help you decide if the stock is worth further research. Aéroports de Paris has a P/E ratio of 26.48, based on the last twelve months. In other words, at today's prices, investors are paying €26.48 for every €1 in prior year profit.

Check out our latest analysis for Aéroports de Paris

How Do You Calculate Aéroports de Paris's P/E Ratio?

The formula for P/E is:

Price to Earnings Ratio = Share Price ÷ Earnings per Share (EPS)

Or for Aéroports de Paris:

P/E of 26.48 = €176.90 ÷ €6.68 (Based on the trailing twelve months to June 2019.)

Is A High Price-to-Earnings Ratio Good?

A higher P/E ratio means that investors are paying a higher price for each €1 of company earnings. That isn't a good or a bad thing on its own, but a high P/E means that buyers have a higher opinion of the business's prospects, relative to stocks with a lower P/E.

How Does Aéroports de Paris's P/E Ratio Compare To Its Peers?

The P/E ratio indicates whether the market has higher or lower expectations of a company. As you can see below, Aéroports de Paris has a higher P/E than the average company (17.5) in the infrastructure industry.

Its relatively high P/E ratio indicates that Aéroports de Paris shareholders think it will perform better than other companies in its industry classification. The market is optimistic about the future, but that doesn't guarantee future growth. So further research is always essential. I often monitor director buying and selling.

How Growth Rates Impact P/E Ratios

P/E ratios primarily reflect market expectations around earnings growth rates. Earnings growth means that in the future the 'E' will be higher. That means unless the share price increases, the P/E will reduce in a few years. A lower P/E should indicate the stock is cheap relative to others -- and that may attract buyers.

It's great to see that Aéroports de Paris grew EPS by 13% in the last year. And earnings per share have improved by 14% annually, over the last five years. This could arguably justify a relatively high P/E ratio.

Don't Forget: The P/E Does Not Account For Debt or Bank Deposits

It's important to note that the P/E ratio considers the market capitalization, not the enterprise value. So it won't reflect the advantage of cash, or disadvantage of debt. The exact same company would hypothetically deserve a higher P/E ratio if it had a strong balance sheet, than if it had a weak one with lots of debt, because a cashed up company can spend on growth.

Spending on growth might be good or bad a few years later, but the point is that the P/E ratio does not account for the option (or lack thereof).

Is Debt Impacting Aéroports de Paris's P/E?

Net debt is 31% of Aéroports de Paris's market cap. While that's enough to warrant consideration, it doesn't really concern us.

The Verdict On Aéroports de Paris's P/E Ratio

Aéroports de Paris's P/E is 26.5 which is above average (18.0) in its market. Its debt levels do not imperil its balance sheet and it is growing EPS strongly. Therefore, it's not particularly surprising that it has a above average P/E ratio.

When the market is wrong about a stock, it gives savvy investors an opportunity. If the reality for a company is better than it expects, you can make money by buying and holding for the long term. So this free visual report on analyst forecasts could hold the key to an excellent investment decision.

Of course, you might find a fantastic investment by looking at a few good candidates. So take a peek at this free list of companies with modest (or no) debt, trading on a P/E below 20.

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.