The benchmark Top-40 share index fell 0.47 percent to 47822 points, while the All-Share Index dropped 0.44 percent to 54309 points, with Mediclinic leading the falls after reporting lower annual earnings.
The rand traded at 12.9 to the dollar, 1.13 percent firmer than its overnight close.
The currency is trading at its firmest levels since April 24, according to Thomson Reuters' data.
In fixed income, the yield on the benchmark government bond due in 2026 dipped 6 basis points to 8.5 percent.
The yield had fallen by as much as 10.5 basis points earlier in the session, reacting to data that showed CPI slowed to 5.3 percent in April from 6.1 percent in March, below market expectations of a 5.5 percent year-on-year rise.
Markets are focused on the South African Reserve Bank’s interest rate decision today, with economists polled by Reuters expecting it to keep the repo rate unchanged at 7 percent, although the lower inflation boosted hopes for a rate cut later this year.