A recent addition to the ARCH family of econometric models was introduced by Ding, Granger and Engle (1993) wherein the power term by which the data is transformed was estimated within the model rather than being imposed by the researcher. This paper considers the ability of the Power GARCH...

This paper extends the existing literature into the relationship between beta stability and the length of the estimation period. Specifically of our analysis in the use of powerful new econometrics tests and their application to non-US data, namely, Australian monthly stock returns.