South Africa’s telecom group MTN  has met with Nigeria’s Securities and Exchange Commission (SEC) to discuss a possible initial public offering and how it wanted to structure the share sale, the head of Nigeria’s SEC told Reuters.

SEC director general, Mounir Gwarzo, said MTN had discussed the possibility of issuing various classes of shares to targeted investor groups. He said the telecom firm was looking at three different classes, which would be new in Nigeria.

Gwarzo said the commission was willing to support the share sale as long as it was within local laws and advised the telecom firm to ensure retail investors were protected.

MTN is the largest mobile phone operator in Nigeria with 57 million subscribers, and the country accounts for about a third of its revenue.

Africa’s biggest mobile phone operator MTN Group has said it aims to listing its Nigerian unit during 2017, subject to market conditions, part of an agreement with the Nigerian government.

In June the telecom firm said it would list its local unit on the Nigerian Stock Exchange after agreeing to pay a reduced fine of $1.7 billion in a settlement with the Nigerian government over unregistered SIM cards.

Gwarzo said the company was yet to submit a formal application for the share sale, he told Reuters.

MTN Nigeria has appointed Stanbic IBTC Capital, Standard Bank of South Africa and Standard Advisory London, and Citigroup Global Markets, as joint transaction advisors and global coordinators, with Stanbic acting as lead issuer.