The FTSE/JSE Africa All Share Index is up more than 7 in dollar terms in May, on track for its biggest monthly gain since June last year and its best May performance since 2013. It has outperformed emerging market peers as well as the S P 500 and the Stoxx Europe 600.
The largest contributor to the rally has been tech investor Naspers, which soared after China's Tencent Holdings in which it owns a stake, reported a faster-than-anticipated 13 rise in sales.
Naspers, which accounts for more than 12 of the index, contributed one fifth of the monthly gain in index points. That's almost three times as much as any of the next three stocks, which include two platinum miners and Prosus which holds Naspers' stake in Tencent.
Whether the rally continues will depend on the South African coalition government's commitment to push through economic reforms, metal prices and the 'sell America" trade that is driving investment to developing nations, said Peter Takaendesa, head of equities at Mergence Investment Managers .
Platinum producers Sibanye Stillwater, Northam Platinum and Impala Platinum were also among the top performers as the metal rose to a two-year high.