Nigerian billionaire Aliko Dangote launched Africa's largest share sale yet with the initial public offering of his oil refinery, opening up ownership of the plant to retail investors and raising money for its expansion ↧ How does Aliko Dangote's oil refinery fit into his conglomerate? Nigeria's Dangote Group is selling a 3.3% stake in its 700,000 barrels-per-day oil refinery to the public, in what is expected to be the continent's biggest such transaction.