We present a flexible class of hierarchical copulas capable of modelling multidimensional joint distributions of asset returns with a richer rank correlation structure than existing models. We derive estimators and simulation techniques. The methods are applied to an illustrative portfolio consisting of a subset of DAX stocks.Copulas, Portfolio management, Risk management, Insurance mathematics,
Motivated by repeated spikes and crashes during previous decades we investigate whether the heavily financialized market for crude oil has been driven by speculative bubbles. In our theoretical modeling we draw on the convenience yield approach in order to approximate the fundamental value of the oil price. We separate the oil price fundamental from the bubble component by expressing a standard present-value oil price model in state-space form. We then introduce two Markov-regimes into the statespace representation in order to distinguish between two distinct phases in the bubble process, namely one in which the oil price bubble is a stable process and one in which the bubble explodes. We estimate the entire Markov-switching state-space specification using an econometrically robust Bayesian Markov-Chain-Monte-Carlo (MCMC) methodology. Based on inferential techniques designed for statistically separating both Markov-regimes in the bubble process from each other, we find robust evidence for the existence of speculative bubbles in recent oil price dynamics.
Mobility indices are popular tools designed to quantify the extent of income changes by aggregating “local” distributional change into a “global” scalar according to some rule. For some mobility measures, this aggregation rule is only implicit in their standard definition. We derive an insightful approximation to the (statistical) aggregation rule for the important class of mobility indices introduced by Shorrocks (Journal of Economic Theory 19 (1978), 376–93) and further generalized by Maasoumi and Zandvakili (Economic Letters 22 (1986), 97–102), which enables us to characterize their normative properties. We also develop methods for estimation and inference. A substantive empirical contribution emerges from the comparison of mobility between the United States and Germany. Our methods reveal why income mobility is higher in Germany than in the United States: Higher German mobility in the bottom of the distribution is combined with an implicitly higher weighting by the mobility index at the bottom.
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