Definitions for "S & P 500"
Standard & Poor's Index of 500 market value weighted securities, which trade on the NYSE, AMEX, or NASDAQ. It is not the 500 largest stocks but includes the companies perceived to be industry leaders. The initial index of 233 companies was first introduced in 1923.
The Standard & Poor's 500 Stock Index. An index made up of 500 stock prices to provide a broad indicator of stock price movements.
An index of 500 stocks widely traded on the New York Stock This index is used as a measure of performance of the overall market. Considered by many to be a much more accurate picture of the market in general.