We build a model with a wide variety of players (liquidity traders, speculators, market makers, financial intermediaries, borrowers and lenders). The paper derives the individual and aggregate behavior of participants who are involved in financial interchanges taking into consideration the capacity of some participants to choose the role they want to play and the capacity to allocate funds between financial intermediaries and markets. It is shown that the values of the parameters are crucial in determining which players will and will not exist.