what is beta? what is alpha? investopedia
What is 'Beta'. Beta is a measure of the volatility, or systematic risk, of a security or a portfolio in comparison to the market as a whole. Beta is used in the capital asset pricing model (CAPM), which calculates the expected return of an asset based on its beta and expected market returns. Beta is also known as the beta coefficient.
Alpha is a measure of the active return on an investment, the performance of that investment compared to a suitable market index. An alpha of 1% means the investment's return on investment over a selected period of time was 1% better than the market during that same period, an alpha of -1 means the investment underperformed the market. Alpha is one of the five key measures in modern portfolio theory: alpha, beta, standard deviation, R-squared and the Sharpe ratio.