<Li> S&P 1500 S&P Global 1200 S&P 100 </Li> <Tr> <Th> Website </Th> <Td> us.spindices.com/indices/equity/sp-500 </Td> </Tr> <P> The Standard & Poor's 500, often abbreviated as the S&P 500, or just "the S&P", is an American stock market index based on the market capitalizations of 500 large companies having common stock listed on the NYSE or NASDAQ . The S&P 500 index components and their weightings are determined by S&P Dow Jones Indices . It differs from other U.S. stock market indices, such as the Dow Jones Industrial Average or the Nasdaq Composite index, because of its diverse constituency and weighting methodology . It is one of the most commonly followed equity indices, and many consider it one of the best representations of the U.S. stock market, and a bellwether for the U.S. economy . The National Bureau of Economic Research has classified common stocks as a leading indicator of business cycles . </P> <P> The S&P 500 was developed and continues to be maintained by S&P Dow Jones Indices, a joint venture majority - owned by S&P Global . S&P Dow Jones Indices publishes many stock market indices such as the Dow Jones Industrial Average, S&P MidCap 400, the S&P SmallCap 600, and the S&P Composite 1500 . It is a free - float capitalization - weighted index, and has many ticker symbols, such as: ^ GSPC, INX, and $SPX . </P>

What is the standard and poor's 500 index