This paper consists of two parts, a theoretical followed by an empirical contribution. We first give a new framework for fractional differencing in discrete time and show how the definition of fractional differencing that is commonly employed in empirical financial applications arises as a...

F tests which test jointly for a unit root and a zero intercept, and so compete against Dickey-Fuller t tests, are shown not to enhance power because they are invariant to the intercept value in the absence of a unit root. Monte Carlo results in the literature that indicate otherwise are shown...

We analyze the effects of monetary policy announcements on stock market liquidity using intraday data. We show that the impairment in liquidity associated with policy announcements occurs primarily after, rather than before, the announcements, and is relatively short-lived, lasting about 1.5...