Starting from the definition of “probability” which provides an approach to monetary and real determinants of exchange rates, that paper tries to explain the relation-ships between the investment choices, business and exchanges rates cycles. The methodological framework is based on the Engel and Hamilton (1991) statistical investigations and an expectation modelling according to Bernanke (1983) work. The empirical results point out, on one hand, a very high option value for the investors in the real sector with respect to the monetary and financial assets. On the other hand, an option value differential according to the countries involved in the international investment process is proved.
