South Africa has also been evicted from the benchmark World Government Bond Index of local currency debt, which could trigger billions of dollars of passive outflows.
The South African government has been forced into repeated bailouts of state companies such as struggling power firm Eskom, which is due to receive more than R100-bn ($6.65-bn) of state money over the next two fiscal years.
Moody’s dropped SA’s rating to Ba1, with the outlook remaining negative - bringing it in line with the subinvestment-grade ratings from peer agencies Fitch and S&P Global.