S&P 100
The S&P 100 Index is a stock market index of United States stocks maintained by Standard & Poor's.
Index options on the S&P 100 are traded with the ticker symbol "OEX". Because of the popularity of these options, investors often refer to the index by its ticker symbol.
The S&P 100, a subset of the S&P 500, includes 100 leading U.S. stocks with exchange-listed options. Constituents of the S&P 100 are selected for sector balance and represent about 57% of the market capitalization of the S&P 500 and almost 45% of the market capitalization of the U.S. equity markets. The stocks in the S&P 100 tend to be the largest and most established companies in the S&P 500.
History
The index was started at the start of 1976. [This conflicts with launch date of 6/15/1983 found on http://us.spindices.com/idsenhancedfactsheet/file.pdf?calcFrequency=M&force_download=true&hostIdentifier=48190c8c-42c4-46af-8d1a-0cd5db894797&indexId=2431]
In 1983, the CBOE created the first index options, based on its own index, the CBOE 100.