South Africa's rand snapped a four-day winning streak against the dollar on Wednesday and traders said a weaker than expected retail sales report could drag the currency lower.
The sales data, due out at 1100 GMT, could help restrain the South African Reserve Bank from raising interest rates next week, further undermining the rand's high-yield advantage as investors brace for policy tightening in the United States.
By 0700 GMT the local currency was down 0.23 per cent at 12.3505 against the dollar compared with where it ended the New York session on Tuesday.
Government bonds were slightly firmer, with the yield on the 2026 benchmark dipping 2 basis points to 8.145 percent.
The rand had been on a firmer footing in the previous four trading sessions, helped by optimism over a bailout package for debt stricken Greece and a nuclear deal between Iran and major world powers.
Traders and analysts however expected renewed pressure as some of the euphoria wore off, with investors turning to Federal Reserve chair Janet Yellen's testimony before Congress for fresh pointers on the timing of U.S. rate hikes.
Expectations that rates will soon go up in the world's biggest economy this year have whittled appetite for riskier emerging currencies like the rand, helping push it nearly seven per cent weaker against the dollar this year.
"Risks are high given Yellen’s key testimony this afternoon, the need for Greece to pass measures in parliament by midnight, and the renewed fall in Chinese equities," Rand Merchant Bank currency analyst John Cairns said in a note.