Answer

In finance, an index typically refers to a statistical measure of change in a securities market. In the case of financial markets, stock and bond market indices consist of a hypothetical portfolio of securities representing a particular market or a segment of it. Each index related to the stock and bond markets has its own calculation methodology. 

The Standard & Poor's 500 is one of the best-known indices and one of the commonly used benchmarks for the stock market.

Go to the NYU Business Library's Industry Information section for links to useful resources including the following suggested resources:  

Standard & Poor's NetAdvantage:  The home screen will provide overview information as well as data on trends and earnings.  Under the S&P 500 Index tab, you will find profile information. The S&P Outlook tab will provide reports. The Quick Screener tab will provide tabs for searching by indices that can be further refined by industry and company data. 

Factiva: The Companies/Markets tab will provide data on a company in relation to an index including S&P indices in chart format.

Datastream: A global financial database which contains current and historical data on stocks, indices, bonds, funds, futures, options, interest rates, commodities, and economic indicators.  Click here for the NYU Datastream Guide.