A foreign investor rarely contracts with the state itself in the context of international economic connections, but rather with one of the state's instrumentalities "that possesses a legal identity separate and autonomous from the State." State enterprises, regulatory bodies, infrastructure agencies, development agencies, and municipal governments are all examples of state instrumentalities. Those instruments must be separated from state institutions, and the existence of legal personhood is central to that separation. An organ is an entity that is not independent of the state and has that status under that state's domestic legislation. The fact that it is closely linked to the state has always fueled debate about the identity of such an enterprise. Whether it is a truly independent entity or merely a state organ hiding behind its legal personality to carry out the state's policies? In response to this question, some argued that the classic distinction between organ and enterprise should be maintained, while others argued that the latter should be a state organ. In this paper, we will focus on the answer provided by investment arbitration jurisprudence (II) to this question, and then we will look at how some recent and important free trade agreements have approached the issue in order to create their own lex specialis set of rules on the subject (III).