Financial security of companies is of the strategic importance. An effective credit risk management greatly impacts on a company security because its failure can threaten the existence of the company. These aspects are closely related to the sustainability of the SME sector, which is determined by many negative processes in the current post-crisis period. The aim of this article is to research the dependence between the entrepreneur’s ability to manage the credit risk in their company effectively and their knowledge of the corporate capital. Within the set goal, we looked at the differences in the attitudes of entrepreneurs depending on a company size, gender and education of entrepreneurs. To analyze acquired data, we used descriptive statistics, regression analyses and Z-score in our research. The originality of the article is that the whole process and result trajectory is focused on highlighting the financial security and sustainability of the searched sector. The results of our research brought an interesting finding. On the one hand, entrepreneurs declared a high capability of the effective credit risk management in their companies and, on the other hand, demonstrated a low level of knowledge in managing the corporate capital. This trend creates a potential possibility of a growth of corporate financial risks. The research results confirmed that the theoretical knowledge of the corporate capital has a significant impact on the formation of effective attitudes of the entrepreneur to manage the credit risk. Larger companies, men and entrepreneurs with higher education have much better level of knowledge of the corporate capital management. The research results enable to form a platform for a deeper insight into the financial security processes in companies and in the sustainability of the SME sector, especially in the current post-crisis period.