Out-of-sample testing on portfolio performance in the Asian equity market: Can optimized portfolio outperformed simpler strategy?

Objectives The main objectives of this study were to examine the performance of different asset allocation strategy in the Asian market by using out-of-sample testing method. The secondary objective is to determine whether optimized portfolios outperformed other portfolios with simpler strategy such as equally-weighted portfolio (EWP) and value-weighted market portfolio (VWMP). Summary This study collected market return, return of assets formed on size, book-to-market and momentum from 1991 to 2018. Optimized portfolios will be formed based on these return, and will be test against the EWP in the period from 2011 to 2018 and few more sub periods. The findings were analyzed by using t-test, f-test, Jobson and Korkie test, and capital accumulation. Conclusions Overall, there is no statistical evidence to conclude that optimized portfolios performed better than the EWP, and the other around, there is no statistical evidence to conclude that the EWP outperformed optimized portfolio. This result is mostly due to the estimation error when constructing optimized portfolio. However, the minimum variance portfolio that shrinks the covariance matrix and allows short, in general, delivers better performance in terms of risk-adjusted return. From a practitioner viewpoint, therefore, one should choose this strategy for asset allocation

Portfolio choice and estimation risk : a comparison of Bayesian approaches to resampled efficiency

Estimation risk is known to have a huge impact on mean/variance (MV) optimized portfolios, which is one of the primary reasons to make standard Markowitz optimization unfeasible in practice. Several approaches to incorporate estimation risk into portfolio selection are suggested in the earlier literature. These papers regularly discuss heuristic approaches (e.g., placing restrictions on portfolio weights) and Bayesian estimators. Among the Bayesian class of estimators, we will focus in this paper on the Bayes/Stein estimator developed by Jorion (1985, 1986), which is probably the most popular estimator. We will show that optimal portfolios based on the Bayes/Stein estimator correspond to portfolios on the original mean-variance efficient frontier with a higher risk aversion. We quantify this increase in risk aversion. Furthermore, we review a relatively new approach introduced by Michaud (1998), resampling efficiency. Michaud argues that the limitations of MV efficiency in practice generally derive from a lack of statistical understanding of MV optimization. He advocates a statistical view of MV optimization that leads to new procedures that can reduce estimation risk. Resampling efficiency has been contrasted to standard Markowitz portfolios until now, but not to other approaches which explicitly incorporate estimation risk. This paper attempts to fill this gap. Optimal portfolios based on the Bayes/Stein estimator and resampling efficiency are compared in an empirical out-of-sample study in terms of their Sharpe ratio and in terms of stochastic dominance

How much foreign stocks? : Bayesian approaches to asset allocation can explain the home bias of US investors

US investors hold much less foreign stocks than mean/variance analysis applied to historical data predicts. In this article, we investigate whether this home bias can be explained by Bayesian approaches to international asset allocation. In contrast to mean/variance analysis, Bayesian approaches employ different techniques for obtaining the set of expected returns. They shrink sample means towards a reference point that is inferred from economic theory. We also show that one of the Bayesian approaches leads to the same implications for asset allocation as mean-variance/tracking error criterion. In both cases, the optimal portfolio is a combination the market portfolio and the mean/variance efficient portfolio with the highest Sharpe ratio. Applying the Bayesian approaches to the subject of international diversification, we find that substantial home bias can be explained when a US investor has a strong belief in the global mean/variance efficiency of the US market portfolio and when he has a high regret aversion falling behind the US market portfolio. We also find that the current level of home bias can justified whenever regret aversion is significantly higher than risk aversion. Finally, we compare the Bayesian approaches to mean/variance analysis in an empirical out-ofsample study. The Bayesian approaches prove to be superior to mean/variance optimized portfolios in terms of higher risk-adjusted performance and lower turnover. However, they not systematically outperform the US market portfolio or the minimum-variance portfolio

Large-scale portfolios using realized covariance matrix: evidence from the Japanese stock market

The objective of this paper is to examine effects of realized covariance matrix estimators based on intraday returns on large-scale minimum-variance equity portfolio optimization. We empirically assess out-of-sample performance of portfolios with different covariance matrix estimators: the realized covariance matrix estimators and Bayesian shrinkage estimators based on the past monthly and daily returns. The main results are: (1) the realized covariance matrix estimators using the past intraday returns yield a lower standard deviation of the large-scale portfolio returns than the Bayesian shrinkage estimators based on the monthly and daily historical returns; (2) gains to switching to strategies using the realized covariance matrix estimators are higher for an investor with higher relative risk aversion; and (3) the better portfolio performance of the realized covariance approach implied by ex-post returns in excess of the risk-free rate, the standard deviations of the excess returns, the return per unit of risk (Sharpe ratio) and the switching fees seems to be robust to the level of transaction costs.Large-scale portfolio selection; Realized covariance matrix; Intraday data

Improving Portfolio Optimization by DCC And DECO GARCH: Evidence from Istanbul Stock Exchange

In this paper, the performance of global minimum variance (GMV) portfolios constructed by DCC and DECO-GARCH are compared to that of GMV portfolios constructed by sample covariance and constant correlation methods in terms of reduced volatility. Also, the performance of GMV portfolios are tested against that of equally weighted and cap weighted portfolios. Portfolios are constructed from the stocks listed in Istanbul Stock Exchange 30 index (hereafter, ISE-30). The results show that GMV portfolios constructed by DCC-GARCH outperformed the other portfolios. In addition, the performance of GMV portfolios estimated by DCC and DECO-GARCH methods are improved by extending calibration period from three years to four years and lowering rolling window term from one week to one day, while the performances of other GMV portfolios decrease. It shows the effect of time varying variance and dynamic correlations on portfolio optimization at Turkish stock market.DCC-GARCH; DECO-GARCH; GMV portfolio