At 1512 GMT, the rand traded at 18.4025 against the dollar, around 0.2% weaker than its previous close.
In March, S&P downgraded its outlook to stable from positive, citing infrastructure constraints and a severe power crisis. In May it had held off from changing the country's sovereign credit rating or outlook.
"We expect either a drop to a negative outlook or for the agency to wait until the February budget to decide if it needs to make a change," Investec analyst Lara Hodes said in a research note.
Next week, the South African Reserve Bank will announce its interest rates decision. A Reuters poll found that the central bank will keep its repo rate unchanged and wait until May 2024 before cutting it.
On the stock market, the Top-40 and the broader all-share indexes closed around 0.2% higher.
South Africa's benchmark 2030 government bond was weaker in late deals, with the yield up 2.5 basis point to 10.075%.
(Reporting by Tannur Anders and Anait Miridzhanian; Editing by Nellie Peyton and Stephen Coates)
