What Is a Stock Option?

A stock option gives an investor the right, but not the obligation, to buy or sell a stock at an agreed-upon price and date. There are two types of options: puts, which is a bet that a stock will fall, or calls, which is a bet that a stock will rise. Because it has shares of stock (or a stock index) as its underlying asset, stock options are a form of equity derivative and may be called equity options.