Group Sonangol (Grupo Sonangol) is a parastatal that formerly oversaw petroleum and natural gas production in Angola. The group consisted of Sonangol E.P. (Sociedade Nacional de Combustíveis de Angola, E.P.) and its many subsidiaries. The subsidiaries generally had Sonangol E.P. as a primary client, along with other corporate, commercial, and individual clients. Angola is estimated to have over of offshore and coastal petroleum reserves, and new discoveries are outpacing consumption by a 5-to-1 ratio. In February 2019, the government transferred the industry regulation functions of Sonangol to a new government agency, the National Oil, Gas and Biofuel Agency (ANPG). The ANPG also gained from Sonangol the right to award fossil fuel exploration, development, and production contracts. On the eve of Portuguese Angola's independence from Portugal following the Carnation Revolution and the election of a democratic government in Portugal in 1976, the company ANGOL (ANGOL Sociedade de Lubrificantes e Combustíveis Sarl), founded in 1953 as a subsidiary of Portuguese company SACOR) was nationalized and split in two, forming Sonangol U.E.E. and Direcção Nacional de Petróleos. Directive 52/76 instituted Sonangol as a state-owned company with a mandate to manage the country's substantial petroleum and natural gas. Using the extant remains of Texaco, Total, Shell and Mobil's oil works, Sonangol obtained the assistance of Algerian Sonatrach and of Italian Eni. Oil giant Marathon Oil announced in September 2013 that it had agreed a deal in principle to sell a 10% stake in its offshore Angolan oilfield to Sonangol. In December 2013, Sonangol acquired the exploration rights to five onshore oil blocks in Angola, which could be tendered for development at a later date. In June 2016, president José Eduardo dos Santos removed the entire board of Sonangol, and installed Isabel dos Santos as chairwoman of the company, to "ensure transparency and apply global corporate-governance standards". This led to many accusations of corruption and nepotism.