MTN Group executives may have expected investors to cut them a little slack after they got potential liabilities of US$8.1-billion in Nigeria reduced to $53-million last month. Not so.

MTN stock has risen just 2.8% since the settlement on 24 December, still 20% below its price in late August. That’s when Nigeria’s central bank first alleged that the Johannesburg-based wireless carrier had illegally repatriated funds from its biggest market.

The group faces a Nigerian court hearing on 7 February over a separate claim that it owes $2-billion in back taxes, which it disputes. There’s also the memory of an earlier, $1-billion Nigerian fine levied on the company for failing to disconnect subscribers without proper registration.

“The market is wondering when or if the Nigerian government will want to raid the MTN piggy bank again,” said Nicholas Kunze, a money manager at Sanlam Private Wealth. “The market is asking when will this stop. It’s only two years since the last falling-out.”

MTN is the mobile market leader in Nigeria with about 66 million customers, so it’s also vulnerable to broader risks facing Africa’s biggest oil producing nation, such as a tumbling oil price and next month’s presidential election.

The company is now uninvestable, according to Karin Richards, an independent trader based in Cape Town. “Apart from anything else, the constant claims, all for massive amounts, must be absorbing an extraordinary amount of management time,” she said.