Mikhail Tselishchev | Searcharxiv

arXiv2022

On a Stochastic Model of Diversification

We propose a definition of diversification as a binary relationship between financial portfolios. According to it, a convex linear combination of several risk positions with some weights is considered to be less risky than the probabilistic mixture of the same risk positions with the same weights. It turns out to be that the proposed partial ordering coincides with the well-known second order stochastic dominance, but allows to take a look at it from another perspective.

q-fin.RM↗

arXiv2019

On the Concavity of Expected Shortfall

It is well known that Expected Shortfall (also called Average Value-at-Risk) is a convex risk measure, i. e. Expected Shortfall of a convex linear combination of arbitrary risk positions is not greater than a convex linear combination with the same weights of Expected Shortfalls of the same risk positions. In this short paper we prove that Expected Shortfall is a concave risk measure with respect to probability distributions, i. e. Expected Shortfall of a finite mixture of arbitrary risk positions is not lower than the linear combination of Expected Shortfalls of the same risk positions (with the same weights as in the mixture).

q-fin.RM↗