Portfolio Optimization and Diversification in China: Policy Implications for Vietnam and other Emerging Markets

This article is conducted to examine risk, return, and portfolio optimization at the industry level in China over the period 2007–2016. On the ground of the classical Markowitz framework for portfolio optimization, the mean-semivariance optimization framework is established for China’s stock market at the industry level. Findings from this study indicate that healthcare sector plays a significant role among 10 industries in China on a stand-alone basis. In addition, a significant change of rankings among the sectors in term of risk is found when the mean-semivariance optimization framework is used. We also find that utilizing this new framework helps improve the optimal portfolios in relation to performance, measured by Sortino ratio, and diversification. A simulation technique, generally known as resampling method, is also utilized to check the robustness of the estimates. While the use of this resampling method appears not to improve the performance of optimal portfolios compared with the mean-semivariance framework for China, there is a remarkable advance in diversification of the optimal portfolios. Implications for investors and the governments in Vietnam and other emerging markets have emerged from the study.