Foreign currency sale by Addax Petroleum and increased patronage of Federal Government of Nigeria bonds by foreign investors, yesterday, accounted for an improvement in the value of the naira in the interbank foreign exchange market.

The naira closed at 157.15 to the dollar on the interbank, stronger than the 157.30 it closed on Friday.

Dealers said Addax, part of China's Sinopec Group, sold about $11.5 million to some lenders, while flows from offshore investors buying treasury bills buoyed dollar liquidity.

The naira however, remain unchanged at the twice-weekly auction, as the Central Bank of Nigeria, CBN, sold $150 million at 155.73 to the dollar, the same amount and rate at the previous auction, last week.

"We see the naira strengthening further around the 157 to the dollar mark this week because of anticipated dollar flows from oil companies selling dollars to meet domestic obligations," one dealer said.

Oil firms operating in Nigeria sell dollars periodically to banks to obtain naira to fund their domestic needs.