Standard & Poor's (S&P)

US financial information publishing and securities rating firm which also maintains the CUSIP number system. A part of McGraw-Hill group of companies, it publishes bond Guide, earnings Guide, stock Guide, stock reports, S&P register, and other such material, but is best known for Standard & Poor's 500 composite index. It also maintains indices such as S&P MidCap 400, S&P SmallCap 600, and the S&P 1500 Super composite index that represents 82 percent of the market capitalization of all US stocks traded in the equities market.