Salini test: history and trends of law enforcement practice

The subjectof this article is the international law enforcement practice developing in relation to the concept of investment. The formation of this practice takes place in numerous decisions of investment arbitration. The Salini test plays an important role in this practice, which is an investment arbitration decision that has become the flagship of the development of the practice of applying international investment law and its principles.The purposeof the article is to identify trends in the decisions of investment arbitration, in which the concept of investment is interpreted, as well as in the doctrinal justification of approaches to this problem.The methodologyof the study is a comparative legal analysis of those concepts that are the basis of the Salini test, as well as competing theories with it.Main results. The reason for the appearance of the Salini test was the impossibility of a total consensus of states regarding the legal formalization of the concept of "investment". This impossibility has an objective character, since the investments of resources in one or another sphere have such significant differences that they cannot be taken into account within the framework of a single legal paradigm. In addition, the subjective factor is also important for the formulation of this concept, since states endowed with different roles – either as recipients of investments or as investors have divergent interests that cannot be realized within the framework of a single legal approach.Conclusions. Investment arbitration has to a certain extent demonstrated the ability to overcome the differences that exist between different states regarding the key concept of investment law. It was in the arbitration decisions, and above all in the Salini test, that the signs of the key concept of investment law were identified, which together constitute its content. The content of the Salini test is that the concept of investment is formulated based on the identification of the following criteria: (1) investment of assets; (2) a certain duration of the investment of assets; (3) risky nature of investments; (4) significant economic importance for the recipient state.In addition, the author of the article comes to the conclusion that, despite the fact that the Salini test accumulated the main legal ideas about the regulation of investment activity, the amorphous nature of the concept of investment determines a high degree of its uncertainty in relation to specific situations. This provokes a continuation of the discussion regarding legally significant investment criteria.