The Motembo oil site, located in the province of Matanzas, is the Cuban locality most anciently and durably associated with oil production. Natural oil seeps had been observed there as far back as the Spanish colonial era, and attempts at commercial exploitation were made from the 19th century onward. The Petrolera Nacional de Motembo S.A. carried on this tradition in 1939, issuing $5 shares to finance its extraction operations. This acción No. 000043 (bearing acción No. 1015 in the overall issue order) was issued in Havana on 9 January 1939. The small quantities of oil produced at Motembo never made Cuba an oil-producing country in the strict sense, but the site maintained a symbolically important activity for the Cuban economy for decades.