Earnings per share (EPS) serves as an indicator of a company’s profitability. It is often considered to be one of the most important variables in determining a stock’s value, and it comprises the “E” part of the P/E (priceearnings) valuation ratio. EPS is calculated as:
EPS = net income / average outstanding common shares
There are three basic types of EPS numbers based on where the data comes from:
 Trailing EPS – based on the previous year’s number
 Current EPS – based on this year’s numbers, which are still projections
 Forward EPS – based on future numbers, which are projections
A trailing EPS uses the previous four quarters of earnings in its calculation, and has the benefit of using actual numbers instead of projections. Most price to earnings ratios (P/Es) are calculated using the trailing EPS because it represents what actually happened, and not what might happen. Although the figure is accurate, the trailing EPS is “old news” and many investors will also look at current and forward EPS figures.
The current EPS typically includes the four quarters of the current fiscal year, some of which may have already elapsed, and some of which are yet to come. As a result, some of the data will be based on actual figures and some will be based on projections.
A forward EPS is based purely on projections for some period of time in the future, typically the coming four quarters. Forward EPS estimates can be made by analysts or by the company itself. While this number is based on estimates and not facts, investors are often interested in forward EPS since they want to know about the future earning potential of a company.
Investors often compare the different EPS calculations. Investors, for example, may compare the forward EPS (projections) with the company’s actual earnings per share for the current quarter. If the actual EPS falls short of forward EPS projections, the stock price may fall. If the actual EPS beats estimates, however, the stock may experience a short rally.

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What is the formula for calculating earnings per share (EPS)?
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What is the formula for calculating earnings per share (EPS) in Excel?
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Trailing EPS
The sum of a company's earnings per share for the previous four ... 
Rolling EPS
A measure of a company's earnings per share based on the previous ... 
Forward Price To Earnings  Forward P/E
A measure of the pricetoearnings ratio (P/E) using forecasted ... 
Primary Earnings Per Share (EPS)
One of two methods for categorizing shares outstanding. The other ... 
Earnings Per Share  EPS
The portion of a company's profit allocated to each outstanding ... 
Interim Earnings Per Share
A measure of earnings calculated at a specified time, shorter ...