A Calibration Procedure for Analyzing Stock Price Dynamics in an Agent-Based Framework
41 Pages Posted: 28 Sep 2013 Last revised: 7 Jul 2014
Date Written: July 3, 2014
In this paper we introduce a calibration procedure suitable for the validation of agent based models. Starting from the well-known financial model of Brock and Hommes 1998, we show how an appropriate calibration technique makes the model able to describe price time series. In particular, we formulate the calibration problem as a nonlinear constrained optimization that can be solved numerically via a gradient-based method. The calibration results show that the simplest version of the Brock and Hommes model, with two trader types, fundamentalists and trend-followers, well replicates the price series of four different markets indices: the S&P 500, the Euro Stoxx 50, the Nikkei 225 and the CSI 300. Moreover, we show how the parameter values of the calibrated model are important to interpret the trader behavior on the different investigated markets. These parameters are then used for price forecasting. To further improve the forecasting, we modify our calibration approach by increasing the trader information set and we show how this new method improves the model’s ability in the prediction of market prices.
Keywords: Calibration, Validation, Forecasting, Agent-based models, Asset pricing, Heterogeneous beliefs
JEL Classification: C53, C63, G17
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