MFN Clauses as Bilateral Commitments to Multilateralism A Reply to Simon Batifort and J. Benton Heath

Most-favored-nation (MFN) clauses have been included in international commercial treaties for many centuries. They also figure prominently as standard provisions in almost any international investment agreement (IIA). Their longstanding and widespread use notwithstanding, investment law doctrine and arbitral practice continue to struggle with the clauses’ application and interpretation, in particular as regards their scope of application. What Stanley Hornbeck observed more than one hundred years ago in this Journal, that “there appear[s] constant disagreements and ever-recurring irritation over what is the meaning and what are the obligations attaching to this or that [MFN] clause,” still characterizes the practice of investment tribunals and the literature on MFN clauses in IIAs today.