For companies operating in the global economy, functioning on the basis of existing economic assumptions on equities becomes increasingly difficult. The main source of financing of business assets is shareholders (external sources) and profit remaining in the company (internal sources). Changing market conditions may lead to increased production costs. This imposes on financial managers the need for optimisation of the capital structure of a company. On one hand, they must seek to maximize the profitability of their equity, on the other hand should maintain the level of financial risk within the limits considered to be reasonable, that is not jeopardizing the functioning of the company in the future.