(IDEX Online) - Billionaire Johann Rupert remains the second wealthiest man in Africa, and Nicky Oppenheimer is still number three, according to Forbes' newly-published rich list for 2023.But both men saw their personal and family fortunes dip slightly in a year when the S&P All Africa index plunged by 20 per cent, only to stage a dramatic final-quarter recovery.Rupert, 72, chairman of the Swiss luxury goods firm Compagnie Financiere Richemont, which owns Cartier and Montblanc, is worth $10.7bn, down from $11bn a year ago.Nicky Oppenheimer, 77, (pictured) heir to the De Beers diamond fortune, sold his 40 per cent stake to Anglo American in 2012 for for $5.1bn. His fortune slipped from $8.7m to $8.4m. Both men live in South Africa.The Forbes list Our list billionaires who live or have their primary business in Africa. Net worths are calculated using stock prices and currency exchange rates from mid-January.The richest person in Africa is Aliko Dangote, 65, from Nigeria, with a $13.5bn fortune from cement and sugar.