Benefits of international portfolio diversification: Implication of the Middle Eastern oil-producing countries

This paper aims to investigate opportunities of the short- and long-run international portfolio diversification (IPD) benefits by investing in the Middle Eastern oil-producing countries. Over the past decades, IPD has been the integral feature of global capital markets. Several potential benefits like increasing returns and/or reducing risk have made investors to internationalize their portfolios. Solnik’s theory (1974) approved that gains can be achieved through IPD if returns in the different markets are not perfectly correlated. This may attribute to low correlations of equity returns among different economies. In this regards, there would be a large potential of diversification benefits for investors that diversify into new emerging group of economies such as equity markets of the main oil-producing countries. These markets are often segmented and they may ensure a superior return rate for a given risk level.

In most of the previous studies, Pearson’s correlation test is used to analyze the short-run relationship of market prices. However, recent empirical studies indicate that correlations between equity returns vary over the time. To examine the time-varying conditional correlation, this paper used the dynamic conditional correlation (DCC) model to investigate opportunities of the short-run IPD benefits. In addition, for the long-run linkage analysis, the autoregressive distributed lag (ADRL) approach introduced by Pesaran et al. (2001) is applied.

It is found that, the market returns of the sampled countries are not definitely correlated in the short- and long-term. So, international portfolio investors may get the short- and long-term diversification benefits by diversifying their portfolios among the Middle Eastern equity markets, namely, Iran, Bahrain, Qatar, Kuwait, Oman, Saudi Arabia and UAE.

This paper departs from earlier studies by focusing on the dynamic characteristics of correlation. Two main issues are pursued in this paper. First, instead of modeling the correlation by methods like Pearson correlation coefficient that consider the constant-correlation assumption, this paper directly uses the DCC model. Second, to empirically estimate the long-run relationship among stock markets in the Middle Eastern oil-producing countries, the ARDL approach is utilized. The ARDL approach is more robust and performs well for small sample sizes than other co-integration techniques.