South Africa's Nicky Oppenheimer (pictured) was second on the list, Johann Rupert third.
Christo Wiese was sixth, and Patrice Motsepe eighth.
Desmond Sacco and Stephen Saad are in the top 20, while Cyril Ramaphosa, Lauritz Dippenaar and Raymond Ackerman are in the top 30.
Gerrit Thomas Ferreira, Koos Bekker and Jannie Mouton also feature on the list.
The combined net worth of those listed in the top 40 is R652.6 billion, up 12 percent over last year.
Thirty-two fortunes were self-made, and 19 people are worth more now than they were this time last year.
The average age was 63, Forbes said.