Based on the GDP data from the International Monetary Fund, the size of South Africa’s economy is $301 billion at the rand’s current exchange rate, while Nigeria’s GDP is $296 billion.
Based on the calculation, South Africa beat Nigeria by just $5 billion.
The South African rand has gained more than 16% against the dollar since 2016, while the the Nigerian naira has lost a third of its value this year.
Essentially, the change is due to the depreciation of the naira after the country's central bank removed a currency peg in June.
Despite the development, both countries risk going into recession after contracting in the first quarter of the year.