The article substantiates the need to improve the conceptual and categorical apparatus, which will unambiguously interpret the definition of the term «loss», which, in turn, will contribute to the correct definition of the research subject and tasks by experts. It has been established that the Russian aggression led to the development and adoption of a number of legal acts that will regulate the issue of determining the damage caused to Ukraine. The interpretation of the terms «loss», «lost profit», «economic wastage», which are disclosed in domestic law and scientific works, is analyzed. The provisions of the Law on Accounting and the National Regulation (Standard) of Accounting «General Requirements for Financial Reporting», which regulate the essence of income and profits, are disclosed. It is concluded that the excess of costs over revenues is a loss. The author’s vision of the essence of losses as an economic category is given. It was found that in the current regulations there is no interpretation of the concepts of «lost», «damaged» and «destroyed» property. Provisions of the Draft Law on Protection of Property Rights and Other Real Rights of Persons Victims of Armed Aggression registered with the Verkhovna Rada of Ukraine have been examined. It is established that the concept of «losses» is considered by scientists from two positions: legal and economic. The economic nature of the company’s loss is revealed. It is proved that the difference of approaches in the interpretation of losses and their composition significantly affects the definition of the subject of forensic economic examination. It is revealed that there is a certain debatability of scientific views on determining the subject of forensic economic examination. A matrix has been formed, which summarizes the views of scientists and practitioners on forensic economic expertise.