PE Ratio

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The P/E ratio is the most widely used ratio in the valuation of stocks. It is calculated as: P/E Ratio = Share Price / {Earnings per Share} It can also be calculated from the numbers for the whole company: P/E Ratio = {Market Cap} / {Net Income} There are at least three kinds of P/E ratios used by different investors. They are Trailing Twelve Month P/E Ratio or P/E (ttm), forward P/E, or P/E (NRI). A new P/E ratio based on inflation-adjusted normalized P/E ratio is called {Shiller P/E}, after Yale professor Robert Shiller. In the calculation of P/E (ttm), the earnings per share used are the earnings per share over the past 12 months. For Forward P/E, the earnings are the expected earnings for the next twelve months. In the case of P/E (NRI), the reported earnings less the non-recurring items are used. For the Shiller P/E, the earnings of the past 10 years are inflation-adjusted and averaged. The result is used for P/E calculation. Since it looks at the average over the last 10 years, Shiller P/E is also called PE10.