Nonlinear GARCH Models and Volatility Spillover

Abstract

We extend the class of GARCH models to comprise asymmetric and nonlinear effects on volatility. In particular, we do not only explain future volatility of a time series on its own past, but allow for external influences and spillovers between capital markets. For this generalized class of models, the asymptotic behavior of the Quasi-Maximum-Likelihood estimator of model parameters is derived. The models are applied to time series of fx-rates. It is found that in particular the simple asymmetric models lead to improved performance.