Stock market index option is a type of option, a financial

derivative In mathematics, the derivative of a function of a real variable measures the sensitivity to change of the function value (output value) with respect to a change in its argument (input value). Derivatives are a fundamental tool of calculus. ...

, that is based on stock indices like the

S&P 500 The Standard and Poor's 500, or simply the S&P 500, is a stock market index tracking the stock performance of 500 large companies listed on stock exchanges in the United States. It is one of the most commonly followed equity indices. As of ...

or the

Dow Jones Industrial Average The Dow Jones Industrial Average (DJIA), Dow Jones, or simply the Dow (), is a stock market index of 30 prominent companies listed on stock exchanges in the United States. The DJIA is one of the oldest and most commonly followed equity inde ...

. They give an investor the right to buy or sell the underlying stock index for a defined time period. Because index options are based on a large basket of stocks, investors are able to gain exposure to the market as a whole and take advantage of

diversification Diversification may refer to: Biology and agriculture * Genetic divergence, emergence of subpopulations that have accumulated independent genetic changes * Agricultural diversification involves the re-allocation of some of a farm's resources to ...

. Index options may be tied to the price of either "broad-based indexes" like the

or the

Russell 3000 The Russell 3000 Index is a capitalization-weighted stock market index that seeks to be a benchmark of the entire U.S stock market. It measures the performance of the 3,000 largest publicly held companies incorporated in America as measured by ...

or to "narrow-based indexes", which are limited to a particular industry. The global market for exchange-traded stock market index options is notionally valued by the

Bank for International Settlements The Bank for International Settlements (BIS) is an international financial institution owned by central banks that "fosters international monetary and financial cooperation and serves as a bank for central banks". The BIS carries out its work thr ...

(BIS) at $368,900 million in 2005. A stock index option provides the right to trade a specific stock index at a specified price by a specified expiration date. A call option on a

stock index In finance, a stock index, or stock market index, is an index that measures a stock market, or a subset of the stock market, that helps investors compare current stock price levels with past prices to calculate market performance. Two of the pr ...

gives you the right to buy the index, and a put option on a stock index gives you the right to sell the index. Options on stock indexes are similar to exchange-traded funds (ETFs), the difference being that ETF values change throughout the day whereas the value on stock index options change at the end of each trading day. Therefore, profit/loss on an index option is based on the market's closing price for the day, not on any price during the market's open hours. If an index option is exercised before the close of the market, the buyer of the option will in- or out-of-the-money for an additional amount equal to the difference between the closing price and the exercise price. If the market closes above the intra-day exercise price, then the option will accrue an additional loss, and if the market closes below the intra-day exercise price, the option will accrue an additional gain. For this reason, index options are typically closed out after the market has closed.

References

{{econ-stub Derivatives (finance)

See also

References