Nigeria’s securities regulator has approved South African telecoms firm MTN’s listing application for its $5 billion Nigerian unit.

MTN Nigeria registered more than 20 billion shares before the planned listing in the West African country, MTN’s biggest market with 58 million users in 2018 and accounting for a third of the group’s annual core profit.

“MTN sought to come to the market by way of an introduction and they wrote to the SEC (Securities and Exchange Commission) last week requesting for approval to register its existing shares,” the regulator said in a statement on Wednesday.

“That approval has now been granted.”

MTN has faced challenges in Nigeria, ranging from a tax demand to a fine over unregistered SIM cards.

It had said in 2016 it planned to list its local unit on the Nigerian Stock Exchange after agreeing to pay a $1.7 billion fine to settle the SIM card dispute with the government.

MTN previously said it planned to list in the first half of 2019.