A model for intraday stock price movements is considered. The jumpintensity of the logreturn process is a function of the whole history of a hidden marked point process. The aim is to find the conditional law of such intensity given the history of the logreturn process. Under a Markovianity assumption, related with the weak form of market efficiency, classical filtering techniques are used. The law of the jumpintensity, given the history of the logreturn price, is evaluated and a discussion on a particular case is performed.
Mathematics Subject Classifications (2000)91B28 · 91B70 · 93E11 · 60J75 · 60G55.