Nigeria’s telecoms watchdog has given MTN Nigeria a deadline of 16 November to pay a $5.2 billion fine imposed for failing to register the personal details of 5.1 million subscribers, while South Africa’s stock exchange, JSE Ltd, launched an investigation into the timing of the operator’s announcement of its penalty.

A statement by MTN said its CEO (pictured) is “engaging with the Nigerian authorities” and its senior management and advisers are talking to JSE, after the announcement of the fine knocked around 20 percent off the company’s stock price.

“The outcome of the discussion may affect the date. That’s why they are having the discussion so that they can reach a solution,” a Reuters report quoted a spokesman for the Nigerian Communications Commission, the country’s telecoms watchdog, as saying.

The report also said Nigeria’s presidency and internal security agency are involved in the talks.

As for the JSE probe, the head of the regulatory division, Andre Visser, said “the investigation will follow due process to establish whether there have been any breaches of the listings requirements and can be a lengthy process.”

Under South African capital markets rules, companies are required to immediately warn shareholders of price-sensitive information.

Meanwhile, Fitch Ratings has revised MTN Group’s outlook to negative, owing “to the risk of a significant cash outflow due to a substantial fine imposed on MTN’s Nigerian operations, which could increase leverage and pressure MTN’s credit metrics.”