On the Separability of Vector-Valued Risk Measures

Fuente: arXiv
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Main Authors: Ararat, Çağın, Feinstein, Zachary
Format: Preprint
Published: 2024
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author Ararat, Çağın
Feinstein, Zachary
author_facet Ararat, Çağın
Feinstein, Zachary
contents Risk measures for random vectors have been considered in multi-asset markets with transaction costs and financial networks in the literature. While the theory of set-valued risk measures provide an axiomatic framework for assigning to a random vector its set of all capital requirements or allocation vectors, the actual decision-making process requires an additional rule to select from this set. In this paper, we define vector-valued risk measures by an analogous list of axioms and show that, in the convex and lower semicontinuous case, such functionals always ignore the dependence structures of the input random vectors. We also show that set-valued risk measures do not have this issue as long as they do not reduce to a vector-valued functional. Finally, we demonstrate that our results also generalize to the conditional setting. These results imply that convex vector-valued risk measures are not suitable for defining capital allocation rules for a wide range of financial applications including systemic risk measures.
format Preprint
id arxiv_https___arxiv_org_abs_2407_16878
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the Separability of Vector-Valued Risk Measures
Ararat, Çağın
Feinstein, Zachary
Risk Management
26E25, 46A20, 46N10, 91G45, 91G70
Risk measures for random vectors have been considered in multi-asset markets with transaction costs and financial networks in the literature. While the theory of set-valued risk measures provide an axiomatic framework for assigning to a random vector its set of all capital requirements or allocation vectors, the actual decision-making process requires an additional rule to select from this set. In this paper, we define vector-valued risk measures by an analogous list of axioms and show that, in the convex and lower semicontinuous case, such functionals always ignore the dependence structures of the input random vectors. We also show that set-valued risk measures do not have this issue as long as they do not reduce to a vector-valued functional. Finally, we demonstrate that our results also generalize to the conditional setting. These results imply that convex vector-valued risk measures are not suitable for defining capital allocation rules for a wide range of financial applications including systemic risk measures.
title On the Separability of Vector-Valued Risk Measures
topic Risk Management
26E25, 46A20, 46N10, 91G45, 91G70
url https://arxiv.org/abs/2407.16878