Discussion Papers 2024

CIRJE-F-1229	"Mean Field Equilibrium Asset Pricing Model with Habit Formation"
Author Name	Fujii, Masaaki and Masashi Sekine
Date	June 2024
Full Paper	PDF file
Remarks	Revised in November 2024, forthcoming in Asia-Pacific Financial Markets.

Abstract
This paper presents an asset pricing model in an incomplete market involving a large number of heterogeneous agents, based on the mean field game theory. The primary objective of this study is to derive the equilibrium risk premium process endogenously by considering the optimal consumption-investment problem and the market clearing condition. In the model, we incorporate habit formation in consumption preferences, which has been widely used to explain various phenomena in financial economics. In order to characterize the market-clearing equilibrium, we derive a quadratic-growth mean field backward stochastic differential equation (BSDE) and study its well-posedness and asymptotic behavior in the large population limit. Additionally, we introduce an exponential quadratic Gaussian reformulation of the asset pricing model, in which the solution is obtained in a semi-analytic form.
Keywords: mean field game, asset pricing, optimal consumption-investment problem, exponential utility, market clearing

Abstract

This paper presents an asset pricing model in an incomplete market involving a large number of heterogeneous agents, based on the mean field game theory. The primary objective of this study is to derive the equilibrium risk premium process endogenously by considering the optimal consumption-investment problem and the market clearing condition. In the model, we incorporate habit formation in consumption preferences, which has been widely used to explain various phenomena in financial economics. In order to characterize the market-clearing equilibrium, we derive a quadratic-growth mean field backward stochastic differential equation (BSDE) and study its well-posedness and asymptotic behavior in the large population limit. Additionally, we introduce an exponential quadratic Gaussian reformulation of the asset pricing model, in which the solution is obtained in a semi-analytic form.

Keywords: mean field game, asset pricing, optimal consumption-investment problem, exponential utility, market clearing