In the conditions of post-crisis recovery of the national economy, the existing development models do not meet the priorities of economic security. The main reason for this is the lack of growth in the real sector of the economy, due to the low level of investment activity of economic entities. The result is a lack of sustainable economic growth, increased dependence on imports of high-tech products and reduced competitiveness of domestic enterprises in global markets. The article proposes a model for assessing financial flows taking into account probabilistic internal and external factors affecting the implementation of investment projects selected according to the criteria of economic, budgetary and social efficiency. The results of economic and mathematical modeling demonstrate that with almost identical volumes of loans and budget guarantees, taking into account refinancing, it is possible to increase the number of financed business entities by 37 % more than in the case of absence of guarantee schemes. Thus, combining the resources of the state and business will significantly improve the financial and credit support of business entities by reducing the price and increasing the size of the parameters of borrowed capital, diversifying the timing of its intended use and facilitating the conditions for obtaining to achieve a socially and economically significant effect. The main criteria for the competitive selection of investment projects for the provision of state guarantees should be the following: economic and budgetary efficiency of the project; availability of production base and qualified personnel necessary for its implementation; share of own funds in the total volume of attracted resources; number of newly created jobs; ratio of wages of employees to the corresponding industry average in the region.