Beta measures the sensitivity of a stock relative to market movements. By definition, the market has a Beta of 1.0. To be consistent with our other indicators, the number we use to express Beta is 100, which is equivalent to the number 1.0. Stocks with a Beta greater than 100 tend to amplify the overall movements of the market. Stocks with a Beta between 0 and 100 tend to move in the same direction as the market, but not as far. The market can be considered as the portfolio of all stocks, so the "average stock" has a Beta of 100.