Asymmetric Correlations in Predicting Portfolio Returns*

Rigorous statistical tests have been designed to detect the existence of asymmetric correlations. However, these tests can hardly further facilitate future investment or risk management because asymmetric correlations are time‐varying and difficult to predict. In this paper, we construct a unified state‐space model, which not only measures in‐sample asymmetric correlations, but also exploit out‐of‐sample asymmetric correlations in the context of predicting portfolio returns. First, we regard time‐varying correlation between market returns and portfolio returns as a state variable and model it as an AR(1) process. Then, we measure future asymmetric correlations based on correlation coefficients between two unpredictable components in market returns and correlation, respectively. Third, we clarify the intuition, calculate asymmetric correlations for two portfolio sets and estimate the economic value of applying our model in asset allocation. Finally, we try to search for potential variables that can explain future asymmetric correlations. The results show that market‐wide liquidity, variance, earning price ratio, and investor sentiment can partially explain the asymmetry correlation phenomenon.     

Law,finance, and emerging market returns

This paper investigates how legal foundation influences the return distribution, the growth rate of market capitalization, the ratio of market capitalization to gross domestic product (GDP) and the correlation structure of emerging market indices with developed market indices. Using a sample of 24 emerging markets, we find that emerging markets from the French [civil] law systems earned higher returns, have higher correlations with the world market portfolio, higher average growth rates in market capitalization and lower average market capitalization to GDP than their English common law counterparts. Finally, most emerging markets returns are more highly correlated to the returns of developed markets with an English common law tradition. Our results suggest that diversification potential is highest with the English common law emerging markets but that the diversification benefits come at the cost of reduced returns.     

Returns on ADRs and arbitrage in emerging markets

In this paper we compare the distributions of ADR returns and the returns of the locally traded shares between Chile and Argentina. This comparison is interesting because both countries are emerging economies with a similar free market orientation and the trading hours in both countries virtually coincide with the trading hours in New York. Argentina and Chile differ, however, in two important aspects: During our sample period: (1) The Argentinean market was completely under a fixed-exchange rate system, while Chile maintained a flexible exchange rate regime; and (2) Argentina did not impose any restrictions on foreign investments, while Chile did. We find that the return distributions of the Chilean ADRs are significantly different from the distributions of the returns on the respective underlying Chilean shares. While the mean returns are the same, the return's S.D. are significantly different. In contrast, the hypothesis that the distributions of the returns on the Argentinean ADRs and the returns on their respective underlying shares are the same cannot be rejected. We then use a threshold model to estimate the transaction costs of trading the ADRs and the locally traded shares. We find that the transaction costs that must be added to the returns spread before arbitrage is possible were between 100 and 200 basis points for Chilean ADRs. It was between 66 and 165 basis points for the Argentinean ADRs. The daily return spread reversion caused by arbitrage activities was estimated to be approximately 30% for Chilean ADRs and 40% for Argentinean ADRs. Finally, we cannot reject the hypothesis that low liquidity was a major factor in the cost difference between the two countries.     

Volatility as an asset class: Holding VIX in a portfolio

Hedging market downturns without sacrificing upside has long been sought by investors. If VIX was directly investable, adding it as a hedge to the S&P 500 would result in significantly improved performance over the equity only portfolio. However, tradable VIX products do not provide the hedge or returns investors seek over long-term horizons. Alternatively, deconstructing VIX to find the key S&P 500 options which drive VIX movements leads to a synthetic VIX portfolio that provides a more effective hedge. Using these options captures correlations and returns similar to VIX, and combined with the S&P 500, outperforms the buy-and-hold index portfolio.     

保险资金投资管理中的风险分散问题研究

组合投资是利用投资组合内各个风险资产之间的相关性来分散风险的,而均值—方差投资组合模型采用的相关性度量—相关系数无法准确地度量风险资产之间的相关性,这必将对组合投资的风险分散效果产生不利影响。本文提出,用理论性质更好的相关性度量来度量风险资产之间的相关性,并建立基于Kendallτ的投资组合模型。通过实证研究发现,在保险资金投资管理中,采用基于Kendallτ的投资组合模型能够取得比均值—方差投资组合模型更好的风险分散效果。     

The conditional relationship between beta and returns: recent evidence from international stock markets

The risk–return relationship is one of the fundamental concepts in finance that is most important to investors and portfolio managers. Finance theory argues that the beta or systematic risk is the only relevant risk measure for investors. However, many studies have showed that betas and returns are not related empirically, no matter in domestic markets or in international stock markets. This paper examines the conditional relationship between beta and returns in international stock markets for the period from January 1991 to December 2000. After recognizing the fact that while expected returns are always positive, realized returns could be positive or negative, we find a significant positive relationship between beta and returns in up market periods (positive market excess returns) but a significant negative relationship in down market periods (negative market excess returns). The results are robust for both monthly and weekly returns and for two different proxies of the world market portfolio. Our findings indicate that beta is still a useful risk measure for portfolio managers in making optimal investment decisions.     

Technology-investing countries and stock return predictability

For 77 technology-investing countries we test whether their stock market returns are predictable. We find that exchange rate returns and U.S. stock excess returns predict stock market returns for most countries in our sample, while crude oil and inflation predict returns of less than 40% of countries. While in out-of-sample tests the evidence of predictability declines, U.S. returns still beat the constant returns model for three-quarters of countries in our sample. A portfolio of all 77 countries offers a mean-variance investor annualized profits of between 5.7% and 8.0%, and profits are maximized when return forecasts are based on U.S. returns.     

Simple technical trading rules of stock returns: evidence from 1987 to 1998 in Chile

This paper tests two of the simplest and most popular trading rules — moving average and trading range break-out — in the Chilean stock market. Overall, our results are similar to the ones of Brock et al. (1992), providing strong support for the technical strategies. In fact, buy signals consistently generate higher returns than sell signals. Moreover, returns following sell signals are negative, which is not easily explained by any of the currently existing equilibrium models. However, we do not observe any difference regarding the risk for the signs of buys and sells, a result explained by the fact that the Chilean stock market is highly concentrated and illiquid.     

Cross‐market correlations and transmission of information

We investigate characteristics of cross‐market correlations using daily data from U.S. stock, bond, money, and currency futures markets using a new multivariate GARCH model that permits direct hypothesis testing on conditional correlations. We find evidence that arrival of information in a market affects subsequent cross‐market conditional correlations in the sample period following the stock market crash of 1987, but there is little evidence of such a relationship in the precrash period. In the postcrash period, we also find evidence that the prime rate of interest affects daily correlations between futures returns. Furthermore, we find that conditional correlations between currency futures and other markets decline steeply a few months before the crash and revert to normal dynamics after the crash. © 2002 Wiley Periodicals, Inc. Jrl Fut Mark 22:1059–1082, 2002     

Volatility and shock interactions and risk management implications: Evidence from the U.S. and frontier markets

The study affords comprehensive evidence of shock and volatility interactions between stock markets of each of the twenty four frontier markets and the U.S. for the period 2006:01 to 2015:07. The results from the recent EDCC-GARCH model of Nakatani and Teräsvirta (2009), which permits for concurrent estimation of shock and volatility interactions as well as dynamic conditional correlations (DCC) across assets, shows unidirectional shock and volatility transmissions from the U.S. to the frontier markets. The conditional correlation between the U.S. and each frontier market is very low or negative, offering diversification benefits to U.S. investors. The DCC exhibits slow decay and is insignificantly impacted by previous period's shocks. The results are very intuitive for optimal portfolio allocations using the traditional capital-based as well as the risk-based allocations. The risk parity approach to portfolio management increases (reduces) allocations to lower (higher) risk assets to improve portfolio diversification while increasing the risk-adjusted returns.     

Asymmetric pricing of implied systematic volatility in the cross‐section of expected returns

Assuming a symmetric relation between returns and innovations in implied market volatility, Ang, A., Hodrick, R., Xing, Y., and Zhang, X. (2006) find that sensitivities to changes in implied market volatility have a cross‐sectional effect on firm returns. Dennis, P., Mayhew, S., and Stivers, C. (2006), however, find an asymmetric relation between firm‐level returns and implied market volatility innovations. We incorporate this asymmetry into the cross‐sectional relation between sensitivity to volatility innovations and returns. Using both portfolio sorting and firm‐level regressions, we find that sensitivity to VIX innovations is negatively related to returns when volatility is rising, but is unrelated when it is falling. The negative relation is robust to controls for other variables, suggesting only the increase in implied market volatility is a priced risk factor. © 2010 Wiley Periodicals, Inc. Jrl Fut Mark 31:34–54, 2011     

Robust estimation of the optimal hedge ratio

When using derivative instruments such as futures to hedge a portfolio of risky assets, the primary objective is to estimate the optimal hedge ratio (OHR). When agents have mean‐variance utility and the futures price follows a martingale, the OHR is equivalent to the minimum variance hedge ratio,which can be estimated by regressing the spot market return on the futures market return using ordinary least squares. To accommodate time‐varying volatility in asset returns, estimators based on rolling windows, GARCH, or EWMA models are commonly employed. However, all of these approaches are based on the sample variance and covariance estimators of returns, which, while consistent irrespective of the underlying distribution of the data, are not in general efficient. In particular, when the distribution of the data is leptokurtic, as is commonly found for short horizon asset returns, these estimators will attach too much weight to extreme observations. This article proposes an alternative to the standard approach to the estimation of the OHR that is robust to the leptokurtosis of returns. We use the robust OHR to construct a dynamic hedging strategy for daily returns on the FTSE100 index using index futures. We estimate the robust OHR using both the rolling window approach and the EWMA approach, and compare our results to those based on the standard rolling window and EWMA estimators. It is shown that the robust OHR yields a hedged portfolio variance that is marginally lower than that based on the standard estimator. Moreover, the variance of the robust OHR is as much as 70% lower than the variance of the standard OHR, substantially reducing the transaction costs that are associated with dynamic hedging strategies. © 2003 Wiley Periodicals, Inc. Jrl Fut Mark 23:799–816, 2003     

An alternative perspective on the relationship between downside beta and CAPM beta

In this paper we derive relationships between the CAPM beta and three measures of downside risk discussed in the literature. The relationships are derived assuming data generating processes in the mean-variance and mean-semivariance frameworks. In a sample of emerging market index returns we highlight that the association between the CAPM beta and downside beta depends on the standard deviation, skewness and kurtosis of the market portfolio return distribution. Therefore choice of risk measure may depend on the market being investigated. We argue that the derived relationships may also help explain anomalous results in empirical investigations.     

Dependence of stock and commodity futures markets in China: Implications for portfolio investment

We examine the recent trends in dependence structure between the fast-growing commodity markets and the stock markets in China. We address this issue by using copula functions that allow for measuring both average and tail dependence. Our results provide evidence of low and positive correlations between these markets, suggesting that commodity futures are a desirable asset class for portfolio diversification. By comparing the market risks of alternative portfolio strategies, we show that Chinese investors can take advantage of commodity futures during different times to realize risk diversification and downside risk reduction benefits.     

基于VaR和两基金分离的投资组合模型

本文使用VaR来度量投资组合的市场风险,构造了一个在可接受期末财富约束条件下,使VaR达到最小的投资组合模型,同时,发现该模型发生了两基金分离现象,因此存在多风险资产情形下的投资组合模型可以退化成为单风险资产情形下的投资组合模型。最后,本文使用简化的单风险模型对我国上海股票市场进行了实证分析,探讨投资者如何在股票和银行借贷中进行最优资产分配。     

Intraday return predictability,portfolio maximisation,and hedging

We examine whether intraday Chinese return predictability is linked to optimal portfolio holding and hedging. We find that: (1) S&P500 futures returns only predict Chinese spot market returns in up to 5-minute of trading with predictability disappearing at higher frequencies of trade; (2) the portfolio weight is maximised at the 5-minute trading frequency, when predictability is the strongest; and (3) when predictability is the strongest, significantly less shorting of the futures is required to minimise risk when a long position is taken in the Chinese market.     

FIRE SALES FORENSICS: MEASURING ENDOGENOUS RISK

We propose a tractable framework for quantifying the impact of loss‐triggered fire sales on portfolio risk, in a multi‐asset setting. We derive analytical expressions for the impact of fire sales on the realized volatility and correlations of asset returns in a fire sales scenario and show that our results provide a quantitative explanation for the spikes in volatility and correlations observed during such deleveraging episodes. These results are then used to develop an econometric framework for the forensic analysis of fire sales episodes, using observations of market prices. We give conditions for the identifiability of model parameters from time series of asset prices, propose a statistical test for the presence of fire sales, and an estimator for the magnitude of fire sales in each asset class. Pathwise consistency and large sample properties of the estimator are studied in the high‐frequency asymptotic regime. We illustrate our methodology by applying it to the forensic analysis of two recent deleveraging episodes: the Quant Crash of August 2007 and the Great Deleveraging following the default of Lehman Brothers in Fall 2008.     

Fama–French in China: Size and Value Factors in Chinese Stock Returns

We investigate the size and value factors in the cross‐section of returns for the Chinese stock market. We find a significant size effect but no robust value effect. A zero‐cost small‐minus‐big (SMB) portfolio earns an average premium of 0.61% per month, which is statistically significant with a t‐value of 2.89 and economically important. In contrast, neither the market portfolio nor the zero‐cost high‐minus‐low (HML) portfolio has average premiums that are statistically different from zero. In both time‐series regressions and Fama–MacBeth cross‐sectional tests, SMB represents the strongest factor in explaining the cross‐section of Chinese stock returns. Our results contradict several existing studies which document a value effect. We show that this difference comes from the extreme values in a few months in the early years of the market with a small number of stocks and high volatility. Their impact becomes insignificant with a longer sample and proper volatility adjustment.     

The demand for risky assets under uncertain inflation : An examination of some widely used assumptions

This paper examines the effect of the following commonly used methods of incorporating random inflation into discrete-time models of the demand for risky assets: 1) the use of a multivariate normal probability distribution for nominal asset returns and the random inflation rate, and 2) the approximation of real asset returns by the difference between nominal returns and the rate of inflation. The combination of these assumptions results in a deceptively simple version of the inflationary capital asset pricing model (CAPM). However, in an approximation-free version of this model the expected value of real wealth does not exist. While it is obvious that mean-variance analysis is not applicable in such models, we also find that the model does not satisfy Ohlson's weakened conditions for a quadratic approximation to the portfolio selection problem. Furthermore, this model is neither a member of the generalized Pareto-Levy nor log-stable class of portfolio models analyzed by Fama, Samuelson, Ohlson, and Struck.     

Multi‐period hedge ratios for a multi‐asset portfolio when accounting for returns co‐movement

This study presents a model to select the optimal hedge ratios of a portfolio composed of an arbitrary number of commodities. In particular, returns dependency and heterogeneous investment horizons are accounted for by copulas and wavelets, respectively. A portfolio of London Metal Exchange metals is analyzed for the period July 1993–December 2005, and it is concluded that neglecting cross correlations leads to biased estimates of the optimal hedge ratios and the degree of hedge effectiveness. Furthermore, when compared with a multivariate‐GARCH specification, our methodology yields higher hedge effectiveness for the raw returns and their short‐term components. © 2008 Wiley Periodicals, Inc. Jrl Fut Mark 28:182–207, 2008