what does a company's beta mean?
Beta is a measure of how a particular stock's price moves relative to the market as a whole. It is usually described as a measure of volatility. There are individual stock betas and industry betas. A beta of one indicates that the stock's price moves exactly with the overall market. For example, if the market goes up 20%, the stock price goes up 20%. Market down 10%, stock down 10%. This is, of course, calculated over a period of months and does not necessarily hold true on a daily basis.