LAGOS (Reuters) – MTN complied with Nigerian fund transfer rules and did not send money out of the country until it obtained regulatory approvals, the South African telecoms company said on Friday, denying allegations that it illegally repatriated $14 billion.

MTN requested “certificates of capital importation (CCI)” for capital brought into Nigeria and dividends were repatriated based on those investments, Ferdi Moolman, chief executive of MTN Nigeria, said in a statement.

“MTN Nigeria only requested for CCIs for foreign capital that was imported into Nigeria, and dividends were externalised on CCIs,” he said.

Nigeria’s upper house of parliament last month agreed to investigate whether Africa’s biggest telecoms company unlawfully repatriated $13.92 billion between 2006 and 2016.

MTN’s Moolman, Nigerian trade minister Okechukwu Elenemah and four lenders appeared at a parliamentary hearing on the matter on Thursday.

Nigerian Senator Dino Melaye had proposed a motion calling for an investigation into MTN’s repatriation of funds.

The move comes as Nigeria struggles with its first recession in a generation and dollar shortages due to low oil prices.

The issue has battered MTN’s shares, which were down on Friday near a 6-1/2 year low at 106.83 rand as of 1006 GMT.

Rafiu Ibrahim, chairman of Nigeria’s senate investigative panel on alleged illegal repatriation of funds, said on Wednesday that a team of international and local accountancy experts and lawyers had been assembled to look into the matter.

Nigeria is MTN’s most lucrative but increasingly most problematic market.

Earlier this year the company agreed to pay a greatly reduced fine of 330 billion naira ($1.08 billion) to end a long running dispute over unregistered SIM cards in Nigeria.

MTN is the largest mobile network operator in Nigeria, which is the continent’s biggest economy and accounts for a third of MTN’s revenue.

(Reporting by Chijioke Ohuocha; editing by Jason Neely)