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, NASDAQ, or the Cboe BZX Exchange.
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. David M. Blitzer has overall responsibility for index security selection. The S&P 500 is a capitalization-weighted index, and is associated with many ticker symbols, such as: ^GSPC, INX, and $SPX, depending on market or website. The S&P 500 differs from the Dow Jones Industrial Average and 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.