Optimization of utility-based shortfall risk: A non-asymptotic viewpoint

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Main Authors: Gupte, Sumedh, A., Prashanth L., Bhat, Sanjay P.
Format: Preprint
Published: 2023
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author Gupte, Sumedh
A., Prashanth L.
Bhat, Sanjay P.
author_facet Gupte, Sumedh
A., Prashanth L.
Bhat, Sanjay P.
contents We consider the problems of estimation and optimization of utility-based shortfall risk (UBSR), which is a popular risk measure in finance. In the context of UBSR estimation, we derive a non-asymptotic bound on the mean-squared error of the classical sample average approximation (SAA) of UBSR. Next, in the context of UBSR optimization, we derive an expression for the UBSR gradient under a smooth parameterization. This expression is a ratio of expectations, both of which involve the UBSR. We use SAA for the numerator as well as denominator in the UBSR gradient expression to arrive at a biased gradient estimator. We derive non-asymptotic bounds on the estimation error, which show that our gradient estimator is asymptotically unbiased. We incorporate the aforementioned gradient estimator into a stochastic gradient (SG) algorithm for UBSR optimization. Finally, we derive non-asymptotic bounds that quantify the rate of convergence of our SG algorithm for UBSR optimization.
format Preprint
id arxiv_https___arxiv_org_abs_2310_18743
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Optimization of utility-based shortfall risk: A non-asymptotic viewpoint
Gupte, Sumedh
A., Prashanth L.
Bhat, Sanjay P.
Machine Learning
We consider the problems of estimation and optimization of utility-based shortfall risk (UBSR), which is a popular risk measure in finance. In the context of UBSR estimation, we derive a non-asymptotic bound on the mean-squared error of the classical sample average approximation (SAA) of UBSR. Next, in the context of UBSR optimization, we derive an expression for the UBSR gradient under a smooth parameterization. This expression is a ratio of expectations, both of which involve the UBSR. We use SAA for the numerator as well as denominator in the UBSR gradient expression to arrive at a biased gradient estimator. We derive non-asymptotic bounds on the estimation error, which show that our gradient estimator is asymptotically unbiased. We incorporate the aforementioned gradient estimator into a stochastic gradient (SG) algorithm for UBSR optimization. Finally, we derive non-asymptotic bounds that quantify the rate of convergence of our SG algorithm for UBSR optimization.
title Optimization of utility-based shortfall risk: A non-asymptotic viewpoint
topic Machine Learning
url https://arxiv.org/abs/2310.18743