South African reserves advanced 2.7 percent in August as a surge in the gold price boosted the value of the country’s bullion holdings.

Gross gold and foreign-currency reserves rose to $51.45 billion from $50.1 billion in July, the Pretoria-based Reserve Bank said on its website today. The median estimate of seven economists surveyed by Bloomberg was for gross reserves to climb to $50.9 billion. Net reserves increased to $49.1 billion from $47.9 billion, more than the $48.4 billion median estimate of six economists.

The spot price of gold jumped 13 percent last month, reaching $1,913.50 an ounce in London on Aug. 23, according to Bloomberg data. Bullion is in the 11th year of a bull market, the longest winning streak since at least 1920, as investors seek to diversify away from equities and some currencies. Gold reserves rose 13 percent to $7.3 billion, the central bank said.

“Gold reserves are likely to have benefited from the strong gain in dollar-gold price as a result of increased global risk aversion during the month,” Standard Bank Group Ltd. analysts led by Johannesburg-based Michael Keenan said in e- mailed comments before the release of today’s data. “We expect the South African Reserve Bank to have been more hesitant to accumulate reserves” in August, given the prevailing worldwide financial turmoil.

The central bank has been accumulating foreign currency to try and moderate a surge in the value of the rand, which has gained 32 percent against the dollar since the start of 2009. The rand fell 4.3 percent against the U.S. currency last month.

Building reserves has come at a cost to the bank, which posted a loss for a second consecutive year of 1.17 billion rand ($165 million) in the 12 months through March. The bank pays more in interest on local-currency debt than it earns on holding foreign-currency assets. – Bloomberg