Assessing Competition in International Economic Law : A Comparison of 'Market Definition' and 'Comparability'

The extent to which market participants are in a competitive relationship constitutes a key element both in competition law and in international economic law. Competition law practice has developed refined economic instruments designed to define relevant markets on the basis of demand substitutability, supply substitutability and potential and future competition. In contrast, many fields of international economic law, such as trade and investment protection, fail to assess actual market situations. This article identifies conceptual differences and similarities between the legal instruments of the two fields of law in order to analyse whether competition law theories of defining relevant markets could also be applied in international economic law