The General Agreement on Trade Services is a World Trade Organization agreement that is the first multilateral agreement provide legally enforceable rules covering all international trade services and investment in the service sector. Attached to the framework agreement are annexes dealing with rules for specific sectors (movement of natural persons, air transport, financial services, telecommunications, etc.). The agreement also provides for exceptions to the principles of national treatment and most-favoured nation treatment. See GATT General Agreement on Tariffs and Trade. Website.