A derivative is a security which 'derives' its value from another underlying (61) instrument, index, or other investment. Derivatives are available based on the performance of stocks, interest rates, currency exchange rates, as well as (62) contracts and various indexes. Derivatives give the buyer greater leverage for a (63) cost than purchasing the actual underlying instrument to achieve the same position. For this reason, when used properly, they can serve to 'hedge' a (64) of securities against losses. However, because derivatives have a date of (65) , the level of risk is greatly increased in relation to their term. One of the simplest forms of a derivative is a stock option. A stock option gives the holder the right to buy or sell the underlying stock at a fixed price for a specified period of time. (46)