Derivatives are financial instruments whose value is based on an underlying asset. There are several types of derivatives including options, futures, swaps, and warrants. Options give the holder the right but not obligation to buy or sell the underlying asset. Warrants are similar to options and allow holders to purchase stock from the issuing company at a specified price. Derivatives can be used for hedging risk, speculation, and gaining leverage. They are valued using models like Black-Scholes or by their market price on exchanges.