UCLA

Modern portfolio theory says that unsystematic risk can always be diversified away. Although it is unrealistic to achieve perfect diversification, people developed different strategies trying to find an optimal portfolio. In this paper, issues of how to make a diversified portfolio are discussed. Six models of tactical portfolio construction strategies are used to make the optimal portfolios using the historical data from Jan. 2007 to Dec. 2009. From the out-of-sample test by market data from Jan. 2010 to Dec. 2011, the classic Markowitz portfolio has the highest wealth added. By comparing the portfolio evaluation parameters, Sharpe ratio suits an individual investor most. And Bayesian portfolio with informative prior scores highest by Sharpe ratio regardless its sensitivity to the accurate market prediction. The paper also demonstrates the application of statistical software R and the "stockPortfolio" package in the stock investment field.