Autoregressive conditional heteroskedasticity models are found in consequence of heteroskedasticity problem in financial time series. In our study, we find that returns of the Istanbul Stock Exchange Food And Beverage Index have an ARCH effect but they have not a unit root problem according to...

It is a stylized fact that trade indicator models (e.g. Madhavan, Richardson, and Roomans (1997) and Huang and Stoll (1997)) underestimate the bid-ask spread. We argue that this negative bias is due to an endogeneity problem which is caused by a negative correlation between the arrival of public...