Alpha is a measure of the so-called
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 etter 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.