Shares outstanding are all the shares of a corporation that have been authorized, issued and purchased by investors and are held by them. They are distinguished from treasury shares, which are shares held by the corporation itself, thus representing no exercisable rights. Shares outstanding and treasury shares together amount to the number of issued shares.

Shares outstanding can be calculated as either basic or fully diluted. The basic count is the current number of shares. Dividend distributions and voting in the general meeting of shareholders are calculated according to this number. The fully diluted shares outstanding count, on the other hand, includes diluting securities, such as warrants, capital notes or convertibles. If the company has any diluting securities, this indicates the potential future increased number of shares outstanding.