Before revision:  In fact the model can be regarded as  the result of the simplest approximation of the optimal control problem and thus considers financial agents of maximum boundedness.
After revision:  In fact the model can be regarded as a general approach. In a second step we consider the case of a fully myopic agent, where we can solve the optimal investment decision of investors analytically. We select the running cost to be the result of the simplest approximation of the optimal control problem and thus considers financial agents of maximum boundedness.