Asymmetric GARCH processes featuring both threshold effect and bilinear structure

A class of asymmetric GARCH models is proposed by combining threshold effect and bilinear structure. The class is referred to as threshold-bilinear GARCH processes. A simulation study demonstrates that the class exhibits diverse asymmetries in volatilities, accommodating existing asymmetric models. Stationarity and existence of moments are discussed. Applications to Korean stock prices are illustrated.