In a crisis state of the economy, there is an obvious trend towards reduction of activities of small and midsize businesses mainly because of the lack of financial resources for their development. Therefore, the search for the effective and precise mechanisms for management of small and midsize businesses is of great current interest nowadays.We believe that systematic analysis of principles and methods of economic and mathematical modeling, considering their huge potential, will enable us to understand the reasons of the stated problems better and to examine the performance of the economic system in general as well as the development of complicated processes occurring in it.The purpose of the paper is to present a stochastic model of optimal credit strategy for an enterprise considering credit payments and income limitations. The model allows identifying the optimal loan amount aimed at maximizing the average income. The structure of the optimal process for the given model is also described. The methods discussed in the study are appropriate to any decision-making context; still, the principal focus of the research is upon their application in business.