  Enlargement of filtrations is a classical topic in the general theory of
stochastic processes. This theory has been applied to stochastic finance in
order to analyze models with insider information. In this paper we study
initial enlargement in a Markov chain market model, introduced by R. Norberg.
In the enlargened filtration several things can happen: some of the jumps times
can be accessible or predictable, but in the orginal filtration all the jumps
times are totally inaccessible. But even if the jumps times change to
accessible or predictable, the insider does not necessarily have arbitrage
possibilities.
