In this paper, we propose two parametric alternatives to the standard GARCH model. They allow the conditional variance to have a smooth time-varying structure of either additive or multiplicative type. The suggested parameterizations describe both nonlinearity and structural change in the...

In this paper we propose a new multivariate GARCH model with time-varying conditional correlation structure. The approach adopted here is based on the decomposition of the covariances into correlations and standard deviations. The time-varying conditional correlations change smoothly between two...

Most standard hypothesis tests have high power only against a limited space of alternative hypotheses. With the advent of new tests for the same hypothesis, claimed to have higher power for some alternatives, but lower for other, the practitioner has to make a choice between alternative tests....