Risk Sharing with Lambda Value at Risk

Abstract

In this paper, we study the risk-sharing problem among multiple agents using lambda value at risk ([Formula: see text]) as their preferences via the tool of inf-convolution, where [Formula: see text] is an extension of value at risk ([Formula: see text]). We obtain explicit formulas of the inf-convolution of multiple [Formula: see text] with monotone Λ and explicit forms of the corresponding optimal allocations, extending the results of the inf-convolution of [Formula: see text]. It turns out that the inf-convolution of several [Formula: see text] is still a [Formula: see text] under some mild condition. Moreover, we investigate the inf-convolution of one [Formula: see text] and a general monotone risk measure without cash additivity, including [Formula: see text], expected utility, and rank-dependent expected utility as special cases. The expression of the inf-convolution and the explicit forms of the optimal allocation are derived, leading to some partial solution of the risk-sharing problem with multiple [Formula: see text] for general Λ functions. Finally, we discuss the risk-sharing problem with [Formula: see text], another definition of lambda value at risk. We focus on the inf-convolution of [Formula: see text] and a risk measure that is consistent with the second-order stochastic dominance, deriving very different expression of the inf-convolution and the forms of the optimal allocations.