The record fine, imposed on South Africa-based telecoms group MTN by the Nigerian Communications Commission (NCC) has been raised back to $5.2bn, publications in local media revealed.

The penalty was imposed on October 26 after MTN Nigeria failed to disconnect 5.1mn customers with unregistered SIM cards in time during August and September. Following top-lever bargaining and a 'small' mistake, the fine was reduced to $3.9bn at the start of December. However, MTN’s failure to pay it by the end of 2015, as stipulated by the regulator, resulted in reinstating the fine to its original size, which is equal to 21% of the budgeted government spending for 2015, to 17.3% of the planned 2016 expenditure, and to 1.2% of the country’s 2014 GDP at current prices.

MTN has not paid the fine as it challenged it in court and awaits the Federal High Court in Lagos to decide on the matter.

In another court action, Nigeria’s attorney general and justice minister Abubakar Malami asked the Federal High Court in Lagos to freeze MTN Nigeria’s accounts in 21 banks so as to prevent the company from transferring its money abroad and thus frustrating the enforcement of the fine. The request was based on the fact that MTN moved $7.7bn made in Nigeria to a foreign account during the period from October 2007 to May 2009, with $936mn transferred in a single day.

However, on January 12 judge Idris Mohammed turned down the application, stating that Malami had not shown enough facts to prove that MTN is about to empty its Nigerian bank accounts. Mohammed said he would rather urgently hear the case filed by MTN and give a judgment shortly.

MTN is the largest mobile operator in Nigeria with some 62.5mn subscribers and about 42% market share. At the same time, Nigeria is MTN’s largest single market, accounting for 27% of its total customer number in 22 countries in Africa and the Middle East. Nigeria also accounts for about a third of MTN’s sales and for nearly half of its EBITDA.

Last week, Nigerian media reported that the NCC had given the green light to MTN to buy local CDMA operator Visafone Communications with its valuable 800MHz spectrum that will allow the company to launch high-speed 4G data services.