Jan 23, 2015/Bloomberg

The naira retreated for a second straight week as measures taken by Nigeria’s central bank failed to stop the decline of a currency battered by falling oil prices.

It depreciated 3.3 percent in the past five days, bringing its two-week decline to 6.5 percent, the most among the 24 African currencies tracked by Bloomberg. It swung between gains and losses on Friday, advancing as much as 4.4 percent and weakening 0.7 percent.

“There’s still a lot of front-loading and a number of investors continue to be jittery,” Adedayo Idowu, an economist at Vetiva Capital Management Ltd., said by phone from Lagos. “It’s about the underlying fundamentals — the crude oil price. Confidence has been jolted by the downtrend.”

The central bank held interest rates at a record high of 13 percent on Jan. 20, less than a month before Nigerians vote in a presidential election where Goodluck Jonathan is seeking another term amid a widening Islamist insurgency. A day later, the regulator issued a circular stopping money changers from buying dollars on the interbank market or at auctions. It also increased lenders’ foreign-currency trading limits in a bid to boost liquidity in the market.

“In terms of the circular, we are yet to see it calm the nerves of the market,” Idowu said.

The central bank may be able to strengthen the interbank rate to 179 or 180 if it “can manage liquidity successfully until the election” and “bridge the supply gap,” Kenneth Asenime and Kunle Ezun, analysts at Ecobank Transnational Inc. in Lagos, said in an e-mailed note Friday.

The Nigerian Stock Exchange All Share Index rose 0.4 percent to 29,812.05, ending two days of losses. Palm-oil processor Presco Plc (PRESCO) led gainers, advancing 5 percent to 29.63 naira by the close. Guaranty Trust Bank Plc (GUARANTY), the biggest lender by market value, was the main contributor, climbing 2 percent to 21 naira.

The gauge is down 14 percent this year, the most among 93 primary global indexes tracked by Bloomberg.