This paper develops a framework to nonparametrically test whether discretevalued irregularly-spaced financial transactions data follow a Markov process. For that purpose, we consider a specific optional sampling in which a continuous-time Markov process is observed only when it crosses some...

This paper presents an endogeneous model for the stochastic dynamics of the bid-ask spread of prices of nancial assets. The model is derived introducing an intermediary and inventory costs in the setting of equilibrium financial markets as described by Platen and Rebolledo (1996)