Dynamic Equilibrium with Insider Information and General Uninformed Agent Utility

Fuente: arXiv
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Main Authors: Detemple, Jerome, Robertson, Scott
Format: Preprint
Published: 2022
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author Detemple, Jerome
Robertson, Scott
author_facet Detemple, Jerome
Robertson, Scott
contents We study a continuous time economy where agents have asymmetric information. The informed agent (``$I$''), at time zero, receives a private signal about the risky assets' terminal payoff $Ψ(X_T)$, while the uninformed agent (``$U$'') has no private signal. $Ψ$ is an arbitrary payoff function, and $X$ follows a time-homogeneous diffusion. Crucially, we allow $U$ to have von Neumann-Morgenstern preferences with a general utility function on $(0,\infty)$ satisfying the standard conditions. This extends previous constructions of equilibria with asymmetric information used when all agents have exponential utilities and enables us to study the impact of $U$'s initial share endowment on equilibrium. To allow for $U$ to have general preferences, we introduce a new method to prove existence of a partial communication equilibrium (PCE), where at time $0$, $U$ receives a less-informative signal than $I$. In the single asset case, this signal is recoverable by viewing the equilibrium price process over an arbitrarily short period of time, and hence the PCE is a dynamic noisy rational expectations equilibrium. Lastly, when $U$ has power (constant relative risk aversion) utility, we identify the equilibrium price in the small and large risk aversion limits.
format Preprint
id arxiv_https___arxiv_org_abs_2211_15573
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Dynamic Equilibrium with Insider Information and General Uninformed Agent Utility
Detemple, Jerome
Robertson, Scott
Mathematical Finance
91G30, 91B69
We study a continuous time economy where agents have asymmetric information. The informed agent (``$I$''), at time zero, receives a private signal about the risky assets' terminal payoff $Ψ(X_T)$, while the uninformed agent (``$U$'') has no private signal. $Ψ$ is an arbitrary payoff function, and $X$ follows a time-homogeneous diffusion. Crucially, we allow $U$ to have von Neumann-Morgenstern preferences with a general utility function on $(0,\infty)$ satisfying the standard conditions. This extends previous constructions of equilibria with asymmetric information used when all agents have exponential utilities and enables us to study the impact of $U$'s initial share endowment on equilibrium. To allow for $U$ to have general preferences, we introduce a new method to prove existence of a partial communication equilibrium (PCE), where at time $0$, $U$ receives a less-informative signal than $I$. In the single asset case, this signal is recoverable by viewing the equilibrium price process over an arbitrarily short period of time, and hence the PCE is a dynamic noisy rational expectations equilibrium. Lastly, when $U$ has power (constant relative risk aversion) utility, we identify the equilibrium price in the small and large risk aversion limits.
title Dynamic Equilibrium with Insider Information and General Uninformed Agent Utility
topic Mathematical Finance
91G30, 91B69
url https://arxiv.org/abs/2211.15573