Malliavin Calculus and Its Application to Robust Optimal Investment for an Insider

In the theory of portfolio selection, there are few methods that effectively address the combined challenge of insider information and model uncertainty, despite numerous methods proposed for each individually. This paper studies the problem of the robust optimal investment for an insider under mode...

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Main Authors: Chao Yu, Yuhan Cheng
Format: Article
Language:English
Published: MDPI AG 2023-10-01
Series:Mathematics
Subjects:
Online Access:https://www.mdpi.com/2227-7390/11/20/4378
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author Chao Yu
Yuhan Cheng
author_facet Chao Yu
Yuhan Cheng
author_sort Chao Yu
collection DOAJ
description In the theory of portfolio selection, there are few methods that effectively address the combined challenge of insider information and model uncertainty, despite numerous methods proposed for each individually. This paper studies the problem of the robust optimal investment for an insider under model uncertainty. To address this, we extend the Itô formula for forward integrals by Malliavin calculus, and use it to establish an implicit anticipating stochastic differential game model for the robust optimal investment. Since traditional stochastic control theory proves inadequate for solving anticipating control problems, we introduce a new approach. First, we employ the variational method to convert the original problem into a nonanticipative stochastic differential game problem. Then we use the stochastic maximum principle to derive the Hamiltonian system governing the robust optimal investment. In cases where the insider information filtration is of the initial enlargement type, we derive the closed-form expression for the investment by using the white noise theory when the insider is ’small’. When the insider is ’large’, we articulate a quadratic backward stochastic differential equation characterization of the investment. We present the numerical result and conduct an economic analysis of the optimal strategy across various scenarios.
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spelling doaj.art-795d39f015fe4addae9b3e34fb019d592023-11-19T17:15:11ZengMDPI AGMathematics2227-73902023-10-011120437810.3390/math11204378Malliavin Calculus and Its Application to Robust Optimal Investment for an InsiderChao Yu0Yuhan Cheng1Department of Mathematical Sciences, Tsinghua University, Beijing 100084, ChinaSchool of Management, Shandong University, Jinan 250100, ChinaIn the theory of portfolio selection, there are few methods that effectively address the combined challenge of insider information and model uncertainty, despite numerous methods proposed for each individually. This paper studies the problem of the robust optimal investment for an insider under model uncertainty. To address this, we extend the Itô formula for forward integrals by Malliavin calculus, and use it to establish an implicit anticipating stochastic differential game model for the robust optimal investment. Since traditional stochastic control theory proves inadequate for solving anticipating control problems, we introduce a new approach. First, we employ the variational method to convert the original problem into a nonanticipative stochastic differential game problem. Then we use the stochastic maximum principle to derive the Hamiltonian system governing the robust optimal investment. In cases where the insider information filtration is of the initial enlargement type, we derive the closed-form expression for the investment by using the white noise theory when the insider is ’small’. When the insider is ’large’, we articulate a quadratic backward stochastic differential equation characterization of the investment. We present the numerical result and conduct an economic analysis of the optimal strategy across various scenarios.https://www.mdpi.com/2227-7390/11/20/4378Malliavin calculusforward integralrobust optimal investmentinsider informationmodel uncertaintystochastic maximum principle
spellingShingle Chao Yu
Yuhan Cheng
Malliavin Calculus and Its Application to Robust Optimal Investment for an Insider
Mathematics
Malliavin calculus
forward integral
robust optimal investment
insider information
model uncertainty
stochastic maximum principle
title Malliavin Calculus and Its Application to Robust Optimal Investment for an Insider
title_full Malliavin Calculus and Its Application to Robust Optimal Investment for an Insider
title_fullStr Malliavin Calculus and Its Application to Robust Optimal Investment for an Insider
title_full_unstemmed Malliavin Calculus and Its Application to Robust Optimal Investment for an Insider
title_short Malliavin Calculus and Its Application to Robust Optimal Investment for an Insider
title_sort malliavin calculus and its application to robust optimal investment for an insider
topic Malliavin calculus
forward integral
robust optimal investment
insider information
model uncertainty
stochastic maximum principle
url https://www.mdpi.com/2227-7390/11/20/4378
work_keys_str_mv AT chaoyu malliavincalculusanditsapplicationtorobustoptimalinvestmentforaninsider
AT yuhancheng malliavincalculusanditsapplicationtorobustoptimalinvestmentforaninsider