MTN Group, responding in detail to allegations that the wireless carrier illegally moved more than US$14bn out of Nigeria, said Central Bank approvals were obtained before any dividends were issued.

“No dividends were declared or paid until the certificates of capital importation were issued and finalised,” Ferdi Moolman, the Nigeria head of the Johannesburg-based company, said in an e-mailed statement on Friday.

A certificate of capital importation is a Central Bank document that allows for the transfer of capital from Nigeria to a foreign investor, according to Guaranty Trust Bank.

MTN shares have slumped 14% to six-year lows since Nigerian politicians raised allegations that the wireless carrier broke the law when repatriating funds from the country, its biggest market, over 10 years starting in 2006.

Moolman appeared before a senate committee on Thursday to defend the company against the claims, which came four months after MTN agreed to pay a regulatory fine of US$1,1bn (R14,4bn) related to an order to disconnect unregistered subscribers.

MTN said some certificates were issued outside a 24-hour requirement for various administrative reasons. The company said it believes its banks followed proper guidelines by notifying the central bank and getting approvals.

“The Central Bank of Nigeria has the authority, and indeed we believe, approved the banks’ applications to issue [the certificates] outside the recommended time frame,” Moolman said in the statement.