The basic sources of financing a company's wealth are the capitals. The capitals are basically defined as the source of financing the assets, namely permanent and circulating ones. If a company wishes to undertake any operation involving possessing certain goods, it has to use its own or foreign capital. The main rule that allows a company to function and develop is the capital's value. Therefore, it is very important to set the factor the company's capital is gained from, which might be own or foreign capitals. Own capitals are the contributions of shareholders, which, depending of the form of the activity of a company or ways the capitals are gained are differently called. Foreign capitals are created from: -credits -loans -other obligations (taxes, leasing, merchant's credits) -dotations, subventions. Foreign capitals can be divided on long and short-term ones. The most obvious way to possess foreign capital are the bank credits, loans from financial institutions or debentures' loans. Long-term credit can finance ventures of investments and beside-investments. Short-term credit can finance present needs of a company caused by the involvement of the capital in calculations, petty investments or by shortage of circulating capital in the firm. Similar form of enlarging foreign capital are loans. The next source or how to fund a company are commitments to the suppliers and receivers. Another way to possess capitals are subventions and dotations. Depending on the form and kind of the business running, a company can attempt to obtain different sort of no-return financial help to gain particular aims (investments, innovations etc.). Emission and sell of the debentures equals getting a credit on the capital's market. By undertaking a decision concerning financing the investment projects a company had to take into consideration not only potential possibilities how to possess the capital, but also the costs of such an action. These costs can heavily influence the effectiveness of the development of a firm. The cost of the capital is calculated by: medium-weighted capital cost, taxation shield and the financial leverage effect.