An option whose underlying entity is an index. Most index options are cash-based. Index options allow investors to trade in a specific industry group or market without having to buy all the stocks individually.
See Also:
Index: A compilation of the prices of several common entities (stocks) into a single number. An index is a group of stocks which can be traded as one portfolio, such as the S&P 500. Broad-based indexes cover a wide range of industries and companies and narrow-based indexes cover stocks in one industry or economic sector.
Option: A contract that gives the owner the right, but not the obligation, to buy or sell a particular asset (the underlying stock) at a fixed price (the strike price) for a specific period of time (until expiration) . The contract also obligates the writer to meet the terms of delivery if the contract right is exercised by the owner.