The Bus Bloc, or Bloc de la Busira-Momboyo, was a huge concession in the Congo Free State, later the Belgian Congo, operated by the Société anonyme belge pour le commerce du Haut-Congo (SAB). It covered land along and between the Busira River and Momboyo River. In the early days the SAB exploited the local people ruthlessly in their demands for rubber, and many died.