The index is designed to measure the total rate of return of a hypothetical “buy-write”, or “covered call”, strategy on the S&P 500 Index. This strategy consists of a hypothetical portfolio consisting of a “long” position indexed to the S&P 500 Index and the sale of a succession of one-month, at- or slightly out-of-the-money S&P 500 Index call options that are listed on the Chicago Board Options Exchange.