The Interplay between Utility and Risk in Portfolio Selection

Fuente: arXiv
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Autori principali: Baggiani, Leonardo, Herdegen, Martin, Khan, Nazem
Natura: Preprint
Pubblicazione: 2025
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author Baggiani, Leonardo
Herdegen, Martin
Khan, Nazem
author_facet Baggiani, Leonardo
Herdegen, Martin
Khan, Nazem
contents We revisit the problem of portfolio selection, where an investor maximizes utility subject to a risk constraint. Our framework is very general and accommodates a wide range of utility and risk functionals, including non-concave utilities such as S-shaped utilities from prospect theory and non-convex risk measures such as Value at Risk. Our main contribution is a novel and complete characterization of well-posedness for utility-risk portfolio selection in one period that takes the interplay between the utility and the risk objectives fully into account. We show that under mild regularity conditions the minimal necessary and sufficient condition for well-posedness is given by a very simple either-or criterion: either the utility functional or the risk functional need to satisfy the axiom of sensitivity to large losses. This allows to easily describe well-posedness or ill-posedness for many utility-risk pairs, which we illustrate by a large number of examples. In the special case of expected utility maximization without a risk constraint (but including non-concave utilities), we show that well-posedness is fully characterised by the asymptotic loss-gain ratio, a simple and interpretable quantity that describes the investor's asymptotic relative weighting of large losses versus large gains.
format Preprint
id arxiv_https___arxiv_org_abs_2509_10351
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Interplay between Utility and Risk in Portfolio Selection
Baggiani, Leonardo
Herdegen, Martin
Khan, Nazem
Mathematical Finance
Portfolio Management
Risk Management
We revisit the problem of portfolio selection, where an investor maximizes utility subject to a risk constraint. Our framework is very general and accommodates a wide range of utility and risk functionals, including non-concave utilities such as S-shaped utilities from prospect theory and non-convex risk measures such as Value at Risk. Our main contribution is a novel and complete characterization of well-posedness for utility-risk portfolio selection in one period that takes the interplay between the utility and the risk objectives fully into account. We show that under mild regularity conditions the minimal necessary and sufficient condition for well-posedness is given by a very simple either-or criterion: either the utility functional or the risk functional need to satisfy the axiom of sensitivity to large losses. This allows to easily describe well-posedness or ill-posedness for many utility-risk pairs, which we illustrate by a large number of examples. In the special case of expected utility maximization without a risk constraint (but including non-concave utilities), we show that well-posedness is fully characterised by the asymptotic loss-gain ratio, a simple and interpretable quantity that describes the investor's asymptotic relative weighting of large losses versus large gains.
title The Interplay between Utility and Risk in Portfolio Selection
topic Mathematical Finance
Portfolio Management
Risk Management
url https://arxiv.org/abs/2509.10351