The contemporaneous call options volume have a significant strong positive feedback effect on the implied volatility, but the contemporaneous feedback effect of volume on the TARCH volatility is insignificant. The contemporaneous feedback effects from the implied volatility and the TARCH...

This paper documents new results that the ability of structural breaks to explain away non-stationary long memory in the forward premium weakens considerably with higher-frequency data. For daily data, removing structural breaks does not make non-stationary long memory stationary, contrary to...