Despite forming an integral part of literature and practitioner knowledge, Markowitz - based optimization has been shown to suffer severe drawback s of estimation errors and sensitivity to input parameters when implemented in practice. The best diversification methods from the perspective of a private investor in real-life situations still remain largely unsolved. Most of the potential diversification benefits so far have primarily been analyzed for internationally diversified stock portfolios, with a focus on the special viewpoint of U.S investors. Studies have suggested that the Mean-Variance optimization can be robustified by the use of robust covariance estimators other than the sample covariance that relies on the classical Maximum Likelihood Estimator. Using a portfolio formed from 2 Emerging Market and 5 Frontier Market indices in Africa, this study sought to compare the performance of the traditional Mean-Variance model against the performance of the Mean-Variance optimization model robustified with the Orthogonalized Gnanadesikan-Kettenring, Minimum Covariance Determinant, Minimum Volume Ellipsoid and shrink estimators, with an aim of recommending the best model applicable to the African emerging and frontier markets investors. The robustified models were found to indeed have better characteristics in terms of gross returns, annualized returns and net portfolio returns over time compared to the traditional Mean-Variance optimization model.
Beaulieu, E. A. (2015). What Dependency Issues? Re-Examining Assumptions about Canada’s Reliance on the US Export Market. School of Public Policy Research Papers, University of Calgary.
Bekaert, G. A., & Urias, M. S. (1996). Diversification, Integration and Emerging Market Closed-End Funds. The Journal of Finance, 51, 835-869. https://doi.org/10.1111/j.1540-6261.1996.tb02709.x
Brinson, G. P., Randolph Hood, L., & Beebower, G. L. (1986). Determinants of Portfolio Performance. Financial Analysts Journal, 42, 39-44. https://doi.org/10.2469/faj.v42.n4.39
Coggeshall, S. A., & Wu, G. (2005). Asset Allocation and Long-Term Returns: An Empirical Approach. SSRN, Article ID: 873184. https://doi.org/10.2139/ssrn.873184
De Roon, F. A., Nijman, T. E., & Werker, B. J. M. (2001). Testing for Mean-Variance Spanning with Short Sales Constraints and Transaction Costs: The Case of Emerging Markets. The Journal of Finance, 56, 721-742. https://doi.org/10.1111/0022-1082.00343
De Santis, G. A., & Gerard, B. (1997). International Asset Pricing and Portfolio Diversification with Time-Varying Risk. The Journal of Finance, 52, 1881-1912. https://doi.org/10.1111/j.1540-6261.1997.tb02745.x
DeMiguel, V. A., & Nogales, F. J. (2009b). Portfolio Selection with Robust Estimation. Operations Research, 57, 560-577. https://doi.org/10.1287/opre.1080.0566
DeMiguel, V. A., Garlappi, L., & Uppal, R. (2009a). Optimal versus Naive Diversification: How Inefficient Is the 1/N Portfolio Strategy? The Review of Financial Studies, 22, 1915-1953. https://doi.org/10.1093/rfs/hhm075
Driessen, J. A., & Laeven, L. (2007). International Portfolio Diversification Benefits: Cross-Country Evidence from a Local Perspective. Journal of Banking & Finance, 31, 1693-1712. https://doi.org/10.1016/j.jbankfin.2006.11.006
Erb, C. B., Harvey, C. R., & Viskanta, T. E. (1994). Forecasting International Equity Correlations. Financial Analysts Journal, 20, 32-45. https://doi.org/10.2469/faj.v50.n6.32
Errunza, V., Hogan, K., & Hung, M.-W. (1999). Can the Gains from International Diversification Be Achieved without Trading Abroad. The Journal of Finance, 54, 2075-2107. https://doi.org/10.1111/0022-1082.00182
Farrelly, T. (2006). Asset Allocation for Robust Portfolios. The Journal of Investing, 15, 53-63. https://doi.org/10.3905/joi.2006.669100
Goetzmann, W. N. (2005). Why Do Individual Investors Hold Under-Diversified Portfolios? Yale School of Management.
Goetzmann, W. N., Li, L., & Geert Rouwenhorst, K. (2001). Long-Term Global Market Correlations (Working Paper No. 8612). National Bureau of Economic Research. https://doi.org/10.3386/w8612
Gupta, R. (2006). Benefits of Diversification into Emerging Equity Markets with Changing Correlations: An Australian Perspective. International Review of Business Research Papers, 2, 22-38.
Harvey, C. R. (1995). Predictable Risk and Returns in Emerging Markets. The Review of Financial Studies, 8, 773-816. https://doi.org/10.1093/rfs/8.3.773
Hicks, J. R. (1962). Liquidity. The Economic Journal, 72, 787-802. https://doi.org/10.2307/2228351
Huber, P. J. (2009). Robust Statistics (2nd ed.). John Wiley & Sons. https://doi.org/10.1002/9780470434697
Ibbotson, R. G. (2010). The Importance of Asset Allocation. Financial Analysts Journal, 66, 18-20. https://doi.org/10.2469/faj.v66.n2.4
Ibbotson, R. G., & Kaplan, P. D. (2000). Does Asset Allocation Policy Explain 40, 90, or 100 Percent of Performance? Financial Analysts Journal, 56, 26-33. https://doi.org/10.2469/faj.v56.n1.2327
Idzorek, T. M. (2006). Developing Robust Asset Allocations. Citeseer.
Jacobs, H. A., Müller, S., & Weber, M. (2009). How Should Private Investors Diversify? An Empirical Evaluation of Alternative Asset Allocation Policies. Journal of Financial Markets, 19, 62-85. https://doi.org/10.2139/ssrn.1471955
Lauprete, G. A. (2003). Robust Portfolio Optimization. In R. Dutter, P. Filzmoser, U. Gather, & P. J. Rousseeuw (Eds.), Developments in Robust Statistics (pp. 235-245). Springer. https://doi.org/10.1007/978-3-642-57338-5_20
Leavens, D. H. (1945). Diversification of Investments. Trusts and Estates, 80, 469-473.
Longin, F. A., & Solnik, B. (2001). Extreme Correlation of International Equity Markets. The Journal of Finance, 56, 649-676. https://doi.org/10.1111/0022-1082.00340
Mao, J. C. (1970). Essentials of Portfolio Diversification Strategy. Journal of Finance, 25, 1109-1121. https://doi.org/10.1111/j.1540-6261.1970.tb00871.x
Marakbi, Z. (2016). Mean-Variance Portfolio Optimization: Challenging the Role of Traditional Covariance Estimation. Master’s Thesis, KTH Royal Institute of Technology Stockholm, Stockholm.
Markowitz, H. M. (1999). The Early History of Portfolio Theory: 1600-1960. Financial Analysts Journal, 55, 5-16. https://doi.org/10.2469/faj.v55.n4.2281
Markowitz, H. M. (2002). The Theory and Practice of Investment Management. John Wiley & Sons.
Marshall, B. R., Nguyen, N. H., & Visaltanachoti, N. (2013). Liquidity Commonality in Commodities. Journal of Banking & Finance, 37, 11-20. https://doi.org/10.1016/j.jbankfin.2012.08.013
Perold, A. F., & Sharpe, W. F. (1995). Dynamic Strategies for Asset Allocation. Financial Analyst Journal, 51, 149-160. https://doi.org/10.2469/faj.v51.n1.1871
Rosadi, D. A., Putranda Setiawan, E., Templ, M., & Filzmoser, P. (2020). Robust Covariance Estimators for Mean-Variance Portfolio Optimization with Transaction Lots. Operations Research Perspectives, 7, Article ID: 100154. https://doi.org/10.1016/j.orp.2020.100154
Solnik, B. H. (1977). Testing International Asset Pricing: Some Pessimistic Views. The Journal of Finance, 32, 503-512. https://doi.org/10.1111/j.1540-6261.1977.tb03288.x
Welsch, R. E., & Zhou, X. (2007). Application of Robust Statistics to Asset Allocation Models. REVSTAT-Statistical Journal, 5, 97-114.