One of the challenges of financial management is the right choice of sources of financing the activity. Challenge, because the optimal size of foreign funding sources can generate an increase in return on equity; and an inappropriate size will result in negative financial results. In this respect, the authors presented the formula for calculating the financial leverage and the effect of financial leverage as well as the influence factors on them, applying different research methods (heuristic methods, critical methods, graphic methods, etc.) so that the importance and the applicability of financial leverage to financial management.