The aim of this paper is to provide an analysis of the Spanish progressive periphrasis <estar + gerundio> that is very often observed because of the corresponding English periphrasis, and shows the paradox that it possesses both stative and dynamic properties. The explanation of this fact is carried out inside the subeventive theory of the mode of action proposed by Pustejovsky (1991) with certain contributions by Moreno Cabrera (2003) and allows us to explain the five values that have been shown in the descriptions of the Spanish periphrasis as well: progressive, detelizer, durativizer, dynamizer and continuative.