What are the Standard & Poor s indexes?
As closely followed benchmarks, the S&P 500 and S&P MidCap 400 indexes are used to describe the U.S. market for large and medium-sized stocks, respectively. Standard & Poor s developed the indexes to perfect a measure of U.S. stock market performance. The S&P 500 was introduced in 1957 and has become a leading indicator of the U.S. equity market. The S&P MidCap 400 was introduced in 1991 and has fast become a leading measure of the mid-sized segment of the market.
