Polzehl, Jörg; Spokoiny, Vladimir - Sonderforschungsbereich Ökonomisches Risiko <Berlin>
GARCH models are widely used in financial econometrics. However, we show by mean of a simple simulation example that the GARCH approach may lead to a serious model misspecification if the assumption of stationarity is violated. In particular, the well known integrated GARCH effect can be...