The Johannesburg Stock Exchange's All Share Index hit a record high at the close Thursday, buoyed by a deal to avoid fiscal tightening in the United States.
Africa's leading index ended the day up nearly half a percent at 40 245 points.
President Barack Obama on Thursday signed into law a deal that avoids the world's largest economy being squeezed simultaneously by a sharp cut in government spending and higher taxes on consumers.
On Wednesday the JSE had already closed above 40 000 for the first time in its 17-year history.
The news was greeted with some relief in Johannesburg.
Despite a rocky year for the mineral-focused South African economy the JSE has risen around six percent over the last 12 months.
The country was plunged into crisis on August 16 when 36 striking miners were shot dead by police.
Economic growth in South Africa more than halved to 1.2 percent in the third quarter, the lowest rate in more than three years.