The General Agreement on Trade in Services (GATS) is the first and only multilateral agreement to subject supply of services to international trading rules. The GATS is part of the World Trade Organization, including its dispute settlement structure. However, and surprisingly perhaps, there is little case law with respect to the key most-favoured-nation (MFN) and national treatment (NT) GATS obligations. After a short summary of the GATS framework for financial services, this article discusses the recent Appellate Body report in the case Argentina – Financial services that provides clarifications (but also opens new questions) regarding the “likeness analysis” to be undertaken when assessing compliance with MFN and NT GATS obligations.