It is shown that for elliptically distributed bivariate random vectors, the riskiness and dependence strength of random portfolios, in the sense of the univariate convex and bivariate concordance stochastic orders respectively, can be simply characterised in terms of the vector's...

In this article, we examine a generalized version of an identity made famous by Stein (1981) who constructed the so-called Stein's Lemma in the special case of a normal distribution. Other works later followed to extend the lemma to the larger class of elliptical distributions, e.g. Landsman...

This paper deals with the estimation of loss severity distribution arising from the historical data on univariate and multivariate losses. We present an innovative theoretical framework where the closed-form expression for the tail conditional expectation (TCE) is derived for the skewed general...

Stein's Lemma, important in statistics and also in capital asset pricing models, is generalized to the case of elliptical class of distributions. The case when the covariance matrix of the underlying distribution does not exist, is also considered. The results are illustrated by multivariate...

This paper introduces a new family of Generalized Hyper-Elliptical (GHE) distributions providing further generalization of the generalized hyperbolic (GH) family of distributions, considered in Ignatieva and Landsman. The GHE family is constructed by mixing a Generalized Inverse Gaussian (GIG)...

We study a multivariate extension of the univariate exponential dispersion Tweedie family of distributions. The class, referred to as the multi-variate Tweedie family (MTwF), on the one hand includes multivariate Poisson, gamma, inverse Gaussian, stable and compound Poisson distributions and on...

Rogers & Shi (1995) have used the technique of conditional expectations to derive approximations for the distribution of a sum of lognormals. In this paper we extend their results to more general sums of random variables. In particular we study sums of functions of dependent random variables...

Abstract One of the fundamental questions in finance is how to select an investment portfolio? The most popular model is the Mean-Variance (MV) model that was presented by Markowitz in 1952. In the MV model, the optimization problem is a constrained quadratic functional. An optimal portfolio...