"The board has decided to exit Nigeria and steps will be taken to achieve this in a manner that does not erode further value."
Africa's biggest telecoms firm said the new black economic empowerment deal would be launched via a public offer next month.
Zambia's financial technology company Zoona has raised $15 million in a Series B round of financing to expand its reach and services.
Dos Santos, the sole nominee, won 2,543 votes, or 99.6 percent.
Burundi's Francine Niyonsaba finished in 1:56.49 to claim the silver, her country's second medal in any sport at the Olympics.