In this paper we present a rather general phenomenological theory of tick-by-tick dynamics in financial markets. Many well-known aspects, such as the Lévy scaling form, follow as particular cases of the theory. The theory fully takes into account the non-Markovian and non-local character of...

We study the volatility of the MIB30-stock-index high-frequency data from November 28, 1994 through September 15, 1995. Our aim is to empirically characterize the volatility random walk in the framework of continuous-time finance. To this end, we compute the index volatility by means of the...

We analyse the time series of overnight returns for the BUND and BTP futures exchanged at LIFFE (London). The overnight returns of both assets are mapped onto a one-dimensional symbolic-dynamics random walk: The “bond walk”. During the considered period (October 1991–January 1994) the...

We analyze the time series of overnight returns for the bund and btp futures exchanged at liffe (London). The overnight returns of both assets are mapped onto a one–dimensional symbolic–dynamics random walk: The “bond walk”. During the considered period (October 1991—January 1994) the...