Billionaire Dangote launches oil refinery 'people's IPO', Africa's biggest ↧ ↧ Billionaire Dangote launches oil refinery 'people's IPO', Africa's ... Nigerian billionaire Aliko Dangote on Monday launched Africa's largest share sale yet with the initial public offering of ‌his oil refinery, targeting the general public to raise as much as $2.1 billion for its expansion.