“The main issue was liquidity and we are convinced that liquidity has come up to the level they desire,” Governor Godwin Emefiele said by phone from Abuja. “It’s gone to a range of about $250 million to $300 million a day.”

JPMorgan placed Africa’s largest economy and oil producer on “index watch negative’’ for its GBI-EM indexes on Jan. 16, saying central bank measures in December had reduced foreign exchange and bond trading and made it difficult for investors to replicate the gauge. The New-York based lender said it would make a decision within five months.

The central bank increased interest rates to a record 13 percent in November in a bid to stem outflows and stabilize the naira, which has weakened 17 percent against the dollar in the past six months, more than any of the 24 African currencies tracked by Bloomberg.

‘Cast in Stone’

When that failed, it cut banks’ foreign-exchange trading limits in December to zero from 1 percent of shareholders’ funds. The limit was moved to 0.5 percent on Jan. 22, shortly after JPMorgan’s announcement.

While there is enough liquidity in the currency market for investors to sell their naira assets, the central bank will keep monitoring the market and could raise the so-called net open position limit again, said Emefiele.

“The NOP isn’t cast in stone,” he said. “We could decide to make it 1 percent tomorrow or we could decide to make it 2 percent the day after tomorrow.”

Foreign investors increased their naira bond holdings almost fivefold in the year after Nigeria, which has a 1.8 percent weighting in the GBI-EM indexes, was included in October 2012, Bank of America Corp. economists Oyin Anubi and Turker Hamzaoglu in London wrote in a Jan. 21 report.