This paper examines the formation and evolution of customary international law in the field of foreign investment (Parts II and III) and its various forms interaction with international treaties, focussing mainly on BITs (Parts IV to IX). Although a comprehensive study on the customary rules for...

This contribution to a symposium on Kiobel v. Royal Dutch Petroleum Co. examines two ways of looking at the question of corporate liability under customary international law. It argues that the Second Circuit was wrong to ask whether a “norm of corporate liability” exists in the abstract and...

Customary international law is one of the three main sources of international law; lamentably, it has historically received little attention from law and economics scholars, despite providing rich material for economic analysis. In this chapter, we provide a concise overview of recent research...

This article examines whether or not the FET standard has become a rule of customary international law. The article contains the first empirical analysis of this question based on the two conditions under which a treaty-based norm can transform into a customary rule. The article will argue that...