Joburg leads Africa's ultra-wealthy list
Johannesburg's wealth has been estimated at US$245-billion (R3.1-trillion).
The city of gold, according to research by AfrAsia Bank and New World Wealth, is home to 18,200 millionaires, 970 multi-millionaires and two billionaires - all in US dollar terms.
Egypt's Cairo follows at US$140-billion total wealth.
Cape Town is Africa's third-richest city with 8200 millionaires, 480 multi-millionaires and five billionaires - with collective wealth totalling US$135-billion.
Others on the rich-city list include Nigeria's Lagos, Kenya's Nairobi, the Angolan capital Luanda, Morocco's Casablanca and Ghana's Accra.
Wealth analyst Andrew Amoils said Johannesburg and Cape Town are both large economic centres "with a lot of high-end jobs. They have both well-developed luxury areas like Bishopscourt, Camps Bay, Bantry Bay, Clifton, Westcliff, Sandhurst, Hyde Park and Houghton."