S&P 100 Index (OEX), Definition
The Standard & Poor's 100 is an index of stocks whose options trade on the Chicago Board Options Exchange. OEX is the symbol for options on the S&P 100 Index. The S&P 100 Index is a market-capitalization weighted index consisting of 100 large blue chip stocks covering a broad-range of industries. The index is used as a benchmark to measure the performance of large cap stocks. OEX options are American Style, meaning they can be exercised on any business day prior to expiration date. OEX options, available in each of the four nearby months, expire on a monthly basis.