The number of shares a security has in the marketplace. In terms of stocks, the number of outstanding shares can help to determine its liquidity. A stock with a large number of outstanding shares may be deemed to be highly liquid, whereas a stock with a relatively few number of outstanding shares may be viewed as being illiquid.
The portion of a company's authorized shares that have been sold to the public and/or that are held by the company's founders or any of the company's shareholders. Stock that is outstanding can be either free-trading or restricted.