Estimation and Testing in Models Containing Both Jump and Conditional Heteroscedasticity.

In this paper, the authors develop a test for the hypothesis that a series (observed in discrete time) is generated by a diffusion process. This test is based on an overidentifying relation between variance and kurtosis parameters that holds for GARCH diffusions. The proposed test is not specific to a particular data frequency and clearly indicates the presence of jumps in dollar exchange rates. To assess the size and intensity of the jumps, the authors estimate a model containing both jumps and conditional heteroskedasticity.