What is the difference between basic shares and fully diluted shares?

Basic shares represent the number of common shares that are outstanding today (or as of the reporting date).  Fully diluted shares equals basic shares plus the potentially dilutive effect from any outstanding stock options, warrants, convertible preferred stock or convertible debt.  In calculating a company’s market value of equity (MVE) we always want to use diluted shares.  Implicitly the market also uses diluted shares to value a company’s stock.