We calculate betas of 3,813 companies using 60 monthly returns each day of December 2001 and January 2002. lt;brgt;lt;brgt;The median of [maximum beta/minimum beta] was 3.07. lt;brgt;lt;brgt;Industry betas are also very unstable. The median (average) of the percentage daily change (in absolute...

The efficient-market hypothesis (EMH) is one of the most important economic and financial hypotheses that have been tested over the past century. Due to many abnormal phenomena and conflicting evidence, otherwise known as anomalies against EMH, some academics have questioned whether EMH is...

In this paper, we document that realized variation measures constructed from high-frequency returns reveal a large degree of volatility risk in stock and index returns, where we characterize volatility risk by the extent to which forecasting errors in realized volatility are substantive. Even...

Several methods have recently been proposed in the ultra high frequency financial literature to remove the effects of microstructure noise and to obtain consistent estimates of the integrated volatility (IV) as a measure of ex-post daily volatility. Even bias-corrected and consistent realized...