Nigeria's telecommunications regulator NCC said on Tuesday it has approved a request by internet provider Visafone to transfer its shares to MTN following its takeover by the South African firm.
MTN bought Visafone in January to improve its broadband services in its biggest market Nigeria.
"The NCC, in line with its procedure granted a Final-Approval to Visafone for the change in its shareholding structure," the regulator said in a statement.
Visafone had also applied to transfer its licence to MTN but this had not yet been approved, NCC said.
MTN come under public scrutiny in Nigeria and agreed in June to pay a fine of 330 billion naira ($1.09 billion) for missing a deadline to disconnect unregistered SIM cards, amid government fears that these may be used by criminals.
Last month, Nigerian lawmakers also accused MTN of illegally transferring $14 billion out of Africa's most populous nation. MTN has denied the accusation.