Shares outstanding are shares of a corporation that have been authorized, issued and purchased by investors and are held by them. They have rights and represent ownership in the corporation by the person that holds the shares. They are distinguished from treasury shares, which are shares held by the corporation itself, having no exercisable rights. Shares outstanding plus treasury shares together amount to the number of issued shares.

Shares outstanding can be calculated as either basic or fully diluted. The basic count means the current number of shares; any dividend distribution or voting in the general assembly is made 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 a potential future rise in the number of shares outstanding.

The number of shares outstanding can be acquired from various sources. In the United States, the number of shares outstanding may be obtained from quarterly filings with the U.S. Securities and Exchange Commission. Quarterly filings are accessible using the US EDGAR. In Germany, those figures are available using the German company register, the central platform for storage of company data. In the Netherlands, the Netherlands Authority for the Financial Markets (AFM) provides on its web site a register of issued capital. For public companies traded in Israel, the number of shares outstanding (also termed "Capital Listed for Trading") is available at the Tel Aviv Stock Exchange website.