Stamps issued by maritime shipping companies have existed since 1847, when a 5-cent stamp was printed for use by the steamer "Lady McLeod" of Trinidad. Many stamps were printed for use by the different shipping companies serving the Finnish archipelago (above).
S:t Lucia Conveyance Co Gauthier Freres (forgery)
Numerous ship lines in the 19th century had their own stamps to be used for their transportations overseas. This was especially so until the World Post Union was formed in 1874.
T.B. Morton (Danube River)
Among the best-known stamps of this kind are those representing the different West Indian companies (often departing from St Thomas in the Danish West Indies), as well as those issued by the companies trafficking the Danube River (above). Other examples are the stamps representing the HAPAG line between Europe and USA and the stamps issued for the traffic on the Suez Canal in 1868.