The goal of portfolio optimization is to nd the portfolio with highest re-
turns. In this case the selection of the optimal portfolio depends on the underly-
ing assumption on behavior of the assets and the choice on a measure of risk. In
Markowitz (1952), the dependence between nancial returns is totally explained by
the linear correlation coecient and ecient portfolios are the conventional mean
variance optimization model. Generally, correlation is used to explain dependence
between random variables in the linear regression, but it may be inappropriate
for the nancial analysis