There are three categories of funds used for financing a project: equity, subordinated debt and senior debt. Many authors define these concepts as sources of funding or source of capital, and at the same time, they use the same term for legal entities, organizations, and institutions, which contribute to project capital. We use the definition of Ye and define, in this case, the capital categories. The analysis of such categories as equity and senior debt in the financing of PPP projects shows that the authors have the same opinion in understanding and characterizing these two categories. Describing them from the perspective of the risk degree and level of the expected income, we see that these are two diametrically opposite extreme categories of capital. Financial instruments being under the notion of subordinated debt are debt fund obligations that are paid after the senior debt and before the payment of dividends on common shares of the company. Financial instruments which are used for the accumulation of funds within the scope of each category are presented in