A company’s “beta” coefficient is a measure of a stock’s volatility in relation to the rest of the market. The Beta is calculated for individual companies using regression analysis.
The beta coefficient is a key parameter in the capital asset pricing model (or CAPM). It measures the part of the asset’s statistical variance that cannot be mitigated by the diversification provided by the portfolio of many risky assets, because it is correlated with the return of the other assets that are in the portfolio.
The Beta coefficient for a publicly traded company can be found in the stock reports of S & P’s NetAdvantage here:
http://www.netadvantage.sandp.com/NASApp/NetAdvantage/index.do
