EPS is a carefully scrutinized metric that is often used as a barometer to gauge a company's profitability per unit of shareholder ownership. As such, earnings per share are a key driver of share prices. It is also used as the denominator in the frequently cited P/E ratio. EPS can be calculated via two different methods: basic and fully While the math may be simple, there are many varieties of EPS being used these days and investors must understand what each one represents, if they're to make informed investment decisions. For example, the EPS announced by a company may differ significantly from what is reported in the financial statements and in the headlines. As a result, a stock may appear over or under-valued depending on the EPS being used. This report will define some of the varieties of EPS and discuss their pros and cons. There are five types of EPS to be defined in the context of the type of "earnings" being used: