The percentage of a stock’s shares outstanding that are not held by individuals and corporations closely associated with the company. Float can give you a good idea of how volatile a stock is likely to be. If a company’s float is small, say 10%-20%, that means there isn’t a big supply available for the public to buy. If demand outstrips this limited supply, the price can shoot up quickly; if that demand dries up, the price can plunge just as fast.