Float shares outstanding represent the number of issued common shares available for open trading on stock exchanges and other financial markets. It excludes closely held or insider shares owned by a company's corporate management and employees, institutional investors who have controlling stakes or seats on the board of directors, or company-owned foundations.
Float shares outstanding are part of the total common shares outstanding, therefore their quantity can not be higher than the total. If the float shares number is high to the total shares outstanding, it means a big amount of shares are unrestricted and available for trading at open markets, which shows a high level of liquidity. If the float shares number is low to the total shares outstanding, it means that there are a lot of closely-held shares and big lot trades by those holders could significantly change the price and volatility of shares.