Derivatives are financial contracts whose value is derived from an underlying asset such as a stock, bond, commodity, currency, or market index. The three main types of derivatives are futures, forwards, and options. Futures and forwards are contracts to buy or sell an asset at a future date, while options provide the right but not obligation to buy or sell an asset. Derivatives allow investors to hedge risk or speculate on changes in the price of the underlying asset. Major derivatives exchanges include the Chicago Board of Trade, Chicago Mercantile Exchange, and the National Stock Exchange of India.