Standard & Poor's (S&P)

Standard & Poor's (S&P) is an investment services company that rates bonds, stock, commercial paper, and insurance companies.

It also compiles influential stock market indexes and publishes reports, guides, and handbooks on financial topics.

The S&P 500 Index is one of the key measures of large-company stock market performance and is also the benchmark for a large number of large-company stock index funds.