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 Financial support from SOC 06/01-2 Grant (Research Division of the University of Chile) and from an institutional grant of the Hewlett Foundation to CEA is greatly acknowledged. All remaining errors are the author's.
INTRODUCTIONThe determination of the optimal hedge ratio is an issue of both practical and theoretical interests as it impacts hedging effectiveness. Recent contributions to the literature on heterogeneous investors and the selection of an optimal hedge ratio have focused on a single commodity in isolation (e.g., In & Kim, 2006a, 2006bLien & Shrestha, 2007). This study presents a generalization of such an approach, in which the selection of optimal hedge ratios is considered for a portfolio composed of several net positions in commodities (i.e., cash position minus a proportion of a futures contract). In particular, an analytical expression is obtained for an optimal vector of hedge ratios and a measure of the degree hedge effectiveness (HE) for such a portfolio. Toward that end, wavelet and copula analysis is used to accommodate for the existence of heterogeneous investors and asset returns dependency, respectively. The empirical application used in this study considers a portfolio composed of cash and futures positions on London Metal Exchange (LME) metals for the sample period July 1993-December 2005. The portfolio choice is based on the grounds of data availability on cash and futures prices at a high frequency. Indeed, wavelet analysis is a computationally intensive statistical tool, which requires long time series (e.g., Gençay, Whitcher, & Selçuk, 2002;Percival & Walden, 2000). In contrast, given that the LME data have been analyzed earlier (e.g., McMillan, 2005), our conclusions can be contrasted with those of previous studies.The simulations we carry out to characterize the distribution functions of the hedge ratios and the degree of HE are performed under two scenarios: with and without accounting for the cross correlations of returns on cash and futures contracts. As mentioned above, dependency is handled by copula analysis, a statistical tool that has recently gained ground in the finance field to extract the dependence structure from the joint probability distribution function of a set of random variables (e.g., Cherubini, Luciano, & Vecchiato, 2004).Indeed, earlier at...