The interest rate differential that matters for capital flows isn't the differential of the policy rate. What matters is the differential of the bond yields, and South African bond yields are still significantly higher than those is in the U.S and in real terms.
Data from the Johannesburg Stock Exchange (JSE) this week showed foreign investors have sold nearly 30 billion rand ($2.10 billion) of government bonds year-to-date.
Foreign investors' share of Russian debt has been on decline for months and its slide accelerated recently amid intensified fears of fresh US sanctions against Moscow.
"The largest exodus (of foreign investors) from the Russian market was observed on particular days with increased volatility due to geopolitical risks," the central bank said in a report on financial markets.