The definition of services trade under the General Agreement on Trade in Services (GATS) is four-pronged, depending on the territorial presence of the supplier and the consumer at the time of the transaction. The four modes of supply are as follows:
Mode 1:Cross-border
Definition: services supplied from the territory of one WTOMember into the territory of any other Member
Example: A user in country A receivesservices from abroad through its telecommunications or postalinfrastructure.
Mode 2:Consumption abroad
Definition: services supplied in the territory of one WTOMember to the service consumer of any other Member
Example: Nationals of country A havemoved abroad as tourists, students, or patients to consume the respective services.
Mode 3:Commercial presence
Definition: services supplied by a service supplier of oneWTO Member, through commercial presence, in the territory of any otherMember
Example: The service is provided within countryA by a locally-established affiliate, subsidiary, or representative office of aforeign-owned and — controlled company (bank, hotel group, constructioncompany, etc.).
Mode 4:Presence of natural persons
Definition: services supplied by a service supplier of oneWTO Member, through the presence of natural persons of a Member in theterritory of any other Member
Example: A foreign nationalprovides a service within country A as an independent supplier (e.g.,consultant, health worker) or employee of a service supplier (e.g. consultancyfirm, hospital, construction company).
See also: https://www.wto.org/english/tratop_e/serv_e/cbt_course_e/c1s3p1_e.htm