At 1540 GMT the rand was 0.41% firmer at 15.1800 per dollar, after hitting a two-week peak of 15.0750 earlier in the immediate aftermath of Powell's speech.

In his speech, Powell said the US economy is in a "favourable place" and the Fed will "act as appropriate" to keep the economic expansion on track.

Markets had been divided on what they thought Powell would say at the Jackson Hole, Wyoming, symposium, with some expecting him to announce a major stimulus measure while others believed he would downplay the chances of a September rate cut.

"It has been a positive trading week for the local currency thanks to global stimulus hopes and a slowdown in domestic inflation, which boost expectations of a (South African Reserve Bank) rate cut," Lukman Otunuga, a senior research analyst at FXTM, said in a note.

Headline consumer price inflation slowed to 4.0% year-on-year in July, data from Statistics South Africa showed on Wednesday, the lowest since January and below a consensus forecast of 4.2%.

Lower inflation against relatively high interest rates marginally supports the rand's carry-yield attraction, but gains based on such data tend to be quickly overtaken by other factors such as high levels of local credit risk and diminishing chances of lower US benchmark rates.

In equities, Johannesburg's broader All-share index fell 0.35% to 53,996 points, while the benchmark Top-40 index declined 0.39% to 48,248 points.

Retailers were among the biggest decliners, with Massmart shedding 7.81% to 40.26 rand, while Shoprite fell 3.61% to 116.29 rand.

"The whole retail index was not looking all that healthy," said Bright Khumalo, portfolio manager at Vestact. "It's a story of volumes; lower volumes as a result of consumers that are wary of what they spend their hard-earned money on."

In fixed income, the yield on the benchmark bond due in 2026 added 0.5 basis points to 8.275%.