Most of Colombia's general cargotrade has been handled by four public ports: Barranquilla,Cartagena, and Santa Marta on the Atlantic coast andBuenaventura on the Pacific coast. These four ports wereconcessioned in 1993 to regional port "societies"established under company law. These societies areresponsible for contracting with port operators for the useof facilities and supervising the facilities' use -they do not provide services directly. New laws abolishedrestrictive labor practices and have allowed stevedoringservices to compete freely at each port. The liberalizationof labor practices along with the privatization of portservices has resulted in large and rapid improvements inproductivity, lower fees for port users, and very attractivereturns for the concessionaires. Productivity levels arehigher than in most newly privatized ports in other LatinAmerican countries - where in many cases the ports have beenprivatized with limited competition. The improvements havebeen realized with low initial investments, though recentlythe port societies have gone beyond investing in shoresideequipment and are starting to invest in infrastructure expansion.