The South African rand slumped against a buoyant dollar on Wednesday as "Trump trades" surged, after Donald Trump won the US election.

Republican Trump recaptured the White House on Wednesday by securing more than the 270 Electoral College votes needed to win the presidency, Edison Research projected, four years after leaving office.

At 1157 GMT, the rand traded at 17.77 against the US dollar , down about 2.2% on its previous close.

The dollar hit a four-month peak and was set for its biggest one-day rise since March 2020. It was last up about 1.8% against a basket of currencies.

"The initial feeling is that Trump will give (South African) President Ramaphosa a lot to think about, which might not be good for the rand," said Danny Greeff, co-head of Africa at ETM Analytics.

Trump's win has fuelled what's known as "Trump trades" with markets anticipating a continuation of his policies, which could mean higher growth in the short term but also potentially inflationary pressures.

Complicating the rand's situation was South Africa's mid-term budget statement last week, said Zain Vawda, market analyst at MarketPulse by OANDA.

The government forecast wider budget deficits and higher debt over the next three years and ratings agency Fitch on Monday said it had doubts over the government's ability to meet some of its targets.

"This leaves the rand vulnerable to further losses against the greenback heading into the festive season," Vawda said.

South Africa's benchmark 2030 government bond also fell, with the yield up 6 basis points to 9.375%.

On the Johannesburg Stock Exchange the Top-40 index was last down about 1.4%.