Transactions in services between the residents of one country and the residents of another country. From the U.S. viewpoint, it consists of exports and imports of services between U.S. residents and foreign residents. It includes both trade within multinational companies (intra-firm trade in services) and trade between unaffiliated parties. It is one of two channels of delivery of services in international markets; the other is sales of services through foreign affiliates of multinational companies.