Subject and purpose of work: The subject of the article is an analysis of the state aid rules by state authorities in the context of calculating the amount of state aid. This problem was discussed on the basis of a relatively new form of assistance repayable instruments. The aim of this article is to identify the noncompliance of the rules generally applicable to the rules for repayable support. Materials and methods: In order to achieve the objectives set, the analysis of the identified problems was based on non-reactive research involving the assessment of available information. It included studies of normative acts, literature of the subject and reports and analyzes. Results: It has been identified that the current form of act on State aid cases does not take into account the specific nature of aid calculation under return instruments, which is that the final value of the state aid is known only after the repayment of the financial instrument. Conclusions: The legislator should adjust the law on proceedings in state aid cases, the more frequently used form of State intervention is repayable finance. The current practice differs from the literal wording of the provisions in question and should therefore be amended to adapt the provisions to this form of aid.