Select the account you'd like to open
Trade CFDs on over 10,000+ shares, FX pairs, commodities, indices and treasuries
Invest in Australian shares, a range of ETFs, warrants, mFunds
The price-to-earnings ratio, or PE ratio, is one of the most widely used methods of valuing a company’s stock. It is used by analysts, investors and traders to help determine whether a company is being fairly valued by the market, relative to its peers. However, it is by no means a fool-proof measure and should be used in conjunction with other measures of valuation and broader research.
The PE ratio is determined by dividing the company’s stock price by its earnings per share, with the resulting figure being the number of years it will take for the business to earn its current price. Here’s an example:
Company X’s stock price is currently $40. The company has 100 million shares on issue and last year had earnings before interest and tax (EBIT) of $200 million, or $2 per share. Dividing 40 by 2 gives us a price-to earnings ratio (also called a “multiple) of 20, meaning it would take 20 years for the company to earn back its valuation at current levels. A trader or investor can then compare company X’s PE ratio with that of other companies to see whether it is fairly valued at present or not. The ratio can also be used across an entire index, such as the S&P 500.
There are two ways of calculating the ratio:
Trailing PE Ratio
This number uses the businesses most recent earnings, taken from company reports.
Forward PE ratio
The forward PE ratio is based on analyst’s projections of a company’s earnings for the year ahead. For instance, if the consensus estimate among analysts was for company X to grow its earnings per share 10% this year to $2.20, its PE ratio falls to 18.18.
Arguably the strongest feature of the PE ratio is that it provides a relatively simple way to compare the valuations of different stocks: you don’t need to be an expert trader to know that a lower PE ratio is preferably to a higher one, all things being equal.
Its major shortcoming, however, is that it’s too simple to be used in isolation. A PE ratio will not tell you how fast a company’s earnings are rising or falling, nor does it tell us anything about a company’s revenue, how much debt it is carrying or whether it is winning or losing market share. This is all-important information that a canny investor would want to know before making a decision to buy or short the stock.
Price to earnings ratios are really only useful for apples-to-apples comparisons, for instance, if General Motors has a ratio of 14 and Ford has a ratio of 18, that’s an indication GM’s stock may be undervalued, or that Ford’s is overvalued. Armed with that information, a trader and investor may form a view about where each stock is heading: is GM due for a rally? Or is Ford’s stock likely to tank?
However, it is also perfectly possible that the divergence in the two company’s ratios is justifiable, which is why more research is needed before making a decision to invest or trade. For instance, Ford’s earnings may be growing, while GM’s may be stagnating or going backwards.
In a word, no: it’s all relative. A company that is growing its earnings quickly deserves a higher multiple than one that is stagnating or growing slowly. That’s why it makes little sense to compare the PE ratio of a tech company with that of a banking stock.
The PE ratio is a good place to start when comparing the valuations of different companies, but there are numerous other methods investors should be aware of. Here are a few other ways to value stocks:
Price/earnings-to-growth (PEG) ratio
The PEG ratio measures a company’s existing PE ratio against the expected growth in its earnings. To calculate this, divide the PE ratio by the rate of growth.
Using the Company X example (a PE ratio of 20, divided by 10% earnings growth) gives us a PEG ratio of 2. As a rule of thumb, analysts usually consider a stock with a PEG ratio of less than 1 to be undervalued.
To determine a stock’s price to sales ratio, investors and traders divide a company’s market value (its share price multiplied by the number of shares on issue) by the value of its revenue or sales over the past year. This is a popular way to value “growth” stocks, especially in the tech space, where sales often grow faster than earnings in the early years. It is also useful in valuing companies that have negative earnings.
Price-to-book (P/B) ratio
The P/B ratio is calculated by dividing a company’s market valuation by its book value – which can be worked out by dividing a company’s market value per share by the value of its assets per share (minus debt). This can be useful when comparing the value of similar companies with similar growth profiles. A P/B ratio of less than one means a company is worth less than the value of its assets, which can be a sign that it is undervalued, but also that the company is in trouble. This metric is especially popular among so-called value investors like Warren Buffett.
The PE ratio is an extremely useful tool for valuing companies, but it shouldn’t be the only item in a trader or investors tool kit. It should be considered alongside other means of valuation, as well as broader research into the company’s performance and prospects.
Investing in CMC Markets derivative products carries significant risks and is not suitable for all investors. You could lose more than your deposits. You do not own, or have any interest in, the underlying assets. We recommend that you seek independent advice and ensure you fully understand the risks involved before trading. Spreads may widen dependent on liquidity and market volatility. The information on this website is prepared without considering your objectives, financial situation or needs. Consequently, you should consider the information in light of your objectives, financial situation and needs. CMC Markets Asia Pacific Pty Ltd ABN 11 100 058 213, AFSL No. 238054 (the derivative product issuer), CMC Markets Stockbroking Limited, Participant of the ASX Group (Australian Securities Exchange) and SSX (Sydney Stock Exchange) and Chi-X (Chi-X Australia), ABN 69 081 002 851, AFSL No. 246381 (the stockbroking services provider) provides the financial products and/or services. It's important for you to consider the relevant Product Disclosure Statement ('PDS') and any other relevant CMC Markets Documents before you decide whether or not to acquire any of the financial products. Our Financial Services Guide contains details of our fees and charges. All of these documents are available at cmcmarkets.com.au or you can call us on 1300 303 888.
Apple, iPad, and iPhone are trademarks of Apple Inc., registered in the U.S. and other countries. App Store is a service mark of Apple Inc. Android is a trademark of Google Inc.