The Angolan president, José Eduardo dos Santos, has appointed his billionaire businesswoman daughter Isabel as head of the state energy firm in a shakeup that cements his grip on power. Isabel would become chief executive after Sonangol’s board was sacked, a presidential decree carried on Angolan state media said.Angola, Africa’s top oil producer because of supply outages caused by militant attacks in Nigeria’s Niger Delta, said in April it would restructure to increase efficiency and profitability. Putting the 43-year-old, ranked by Forbes as Africa’s richest woman, in charge could mean Dos Santos is serious about reforms, but it could also be seen as Angola’s leader of the last 36 years laying the ground for his family to control the central pillar of the economy when he leaves office.Angola’s president says he’s giving up 37-year rule. Should we believe him? Read more Oil sales account for more than 90% of Angola’s foreign exchange earnings, making Sonangol by far the biggest source of dollars and state funding. The president’s son, José Filomeno, is chief executive of Angola’s sovereign wealth fund.Antony Goldman, an independent, Africa-focused energy analyst, said: “Sonangol was always regarded as one of the more effective African national oil companies, but governance has slipped quite considerably over the past decade through issues where political factors played no small part.”Of Isabel dos Santos, he said: “She’s not an engineer or necessarily an energy expert but she is someone with a track record of getting deals done.” London-educated Isabel, who denies any political ambitions and says she started her business career as a six-year-old selling eggs, has been a major investor in the domestic and Portuguese telecoms, banking and petroleum sectors.Cobus de Hart, an Angola analyst at NKC African Economics in Cape Town, said: “The case can certainly be made that this is a political move whereby the president is strengthening his grip. But the news that global consulting firms will be assisting with the reform strategy is at least a step in the right direction.” One senior Johannesburg-based banker said the appointment could make it more difficult for international banks to do business with Sonangol, given the perception of nepotism it creates. “From a compliance point of view, it’s going to make it harder,” the banker said. Sonangol said in February that debt owed to foreign oil companies had soared and it expected a very difficult year. The Opec member imports about 6m cubic metres of refined products a year, according to national statistics.José Eduardo dos Santos, 73, one of Africa’s longest-serving rulers after coming to power in 1979, said in March he intended to step down as president in 2018 but gave no reason for his decision and did not name a preferred successor.Forty years on from independence, Angola still lacks freedom Read more His mild, inscrutable public demeanour belies his tight control of the former Portuguese colony, where he has overseen an oil-backed economic and construction boom to rebuild a country devastated by a 27-year civil war that ended in 2002. Critics accuse him of mismanaging Angola’s oil wealth and making an elite, mainly his family and political allies, vastly rich in a country with widespread poverty.