JOHANNESBURG: South Africa's rand rallied to its best in a week on Wednesday, after data showed the trade surplus widened in February on increased export activity.

At 1500 GMT the rand was 1pc firmer at 14.7675 against the U.S. dollar, and trading at levels last touched on March 23.

South Africa's trade surplus widened to 28.96 billion rand ($1.96 billion) in February from a revised surplus of 12.42 billion rand in January, data from the revenue service showed.

The rand is one of the high-yielding currencies hit by the dollar's recent strength and has been volatile this week, weakening on some days as a patchy recovery reflected in local economic data and a slow rollout of vaccines stifled demand.

"Yield seekers, coupled with thinning markets ahead of the long weekend and month-end trading, led to the rand breaking below R14.80/$," said Paul Muller, executive director at Citadel Global.

Shares on the Johannesburg Stock Exchange (JSE) closed lower on Wednesday as sustained high Treasury yields in the U.S. raised fears of rising borrowing costs for companies and inflow of funds into high-yield frontier markets.

The benchmark FTSE/JSE all-share index slipped by 1.2pc to close at 66,485 points while the bluechip FTSE/JSE top-40 companies' index ended down 1.15pc to 60,881 points.

Banks reported the biggest fall among major sector indexes on worries the local economy would suffer if interest rates go up on the back of rising U.S. Treasury yields, analysts said.

The bank index fell 2.23pc but mining companies, especially those mining precious metals such as platinum and gold firmed up.

Bonds firmed, with the yield on the benchmark 2030 issue down 6 basis points to 9.48pc.