Competitive optimal portfolio selection under mean-variance criterion

Fuente: arXiv
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Main Authors: Shao, Guojiang, Xu, Zuo Quan, Zhang, Qi
Format: Preprint
Published: 2025
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author Shao, Guojiang
Xu, Zuo Quan
Zhang, Qi
author_facet Shao, Guojiang
Xu, Zuo Quan
Zhang, Qi
contents We investigate a portfolio selection problem involving multi competitive agents, each exhibiting mean-variance preferences. Unlike classical models, each agent's utility is determined by their relative wealth compared to the average wealth of all agents, introducing a competitive dynamic into the optimization framework. To address this game-theoretic problem, we first reformulate the mean-variance criterion as a constrained, non-homogeneous stochastic linear-quadratic control problem and derive the corresponding optimal feedback strategies. The existence of Nash equilibria is shown to depend on the well-posedness of a complex, coupled system of equations. Employing decoupling techniques, we reduce the well-posedness analysis to the solvability of a novel class of multi-dimensional linear backward stochastic differential equations (BSDEs). We solve a new type of nonlinear BSDEs (including the above linear one as a special case) using fixed-point theory. Depending on the interplay between market and competition parameters, three distinct scenarios arise: (i) the existence of a unique Nash equilibrium, (ii) the absence of any Nash equilibrium, and (iii) the existence of infinitely many Nash equilibria. These scenarios are rigorously characterized and discussed in detail.
format Preprint
id arxiv_https___arxiv_org_abs_2511_05270
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Competitive optimal portfolio selection under mean-variance criterion
Shao, Guojiang
Xu, Zuo Quan
Zhang, Qi
Optimization and Control
Mathematical Finance
Portfolio Management
We investigate a portfolio selection problem involving multi competitive agents, each exhibiting mean-variance preferences. Unlike classical models, each agent's utility is determined by their relative wealth compared to the average wealth of all agents, introducing a competitive dynamic into the optimization framework. To address this game-theoretic problem, we first reformulate the mean-variance criterion as a constrained, non-homogeneous stochastic linear-quadratic control problem and derive the corresponding optimal feedback strategies. The existence of Nash equilibria is shown to depend on the well-posedness of a complex, coupled system of equations. Employing decoupling techniques, we reduce the well-posedness analysis to the solvability of a novel class of multi-dimensional linear backward stochastic differential equations (BSDEs). We solve a new type of nonlinear BSDEs (including the above linear one as a special case) using fixed-point theory. Depending on the interplay between market and competition parameters, three distinct scenarios arise: (i) the existence of a unique Nash equilibrium, (ii) the absence of any Nash equilibrium, and (iii) the existence of infinitely many Nash equilibria. These scenarios are rigorously characterized and discussed in detail.
title Competitive optimal portfolio selection under mean-variance criterion
topic Optimization and Control
Mathematical Finance
Portfolio Management
url https://arxiv.org/abs/2511.05270