After a remarkable $1.81-billion surge in net worth during the first 96 days of 2023, South African tycoon Johann Rupert’s fortune continues to soar, having increased by an additional $400 million in the past 12 days. The surge has pushed his net worth above $13.1 billion.

According to the Bloomberg Billionaires Index, Rupert is presently the richest man in South Africa and the second-richest billionaire on the African continent.

The recent $400-million boost in his net worth cements his status as one of the wealthiest men in Africa, with year-to-date gains totaling $2.14 billion, making him the only African billionaire to have recorded a net worth gain in excess of $2 billion since the start of the year.

Rupert’s wealth primarily stems from his 9.14 percent ownership of Richemont, a Swiss-based luxury goods group that boasts high-end brands like Cartier, Chloe, Dunhill, Alaa, and Delvaux. As a result, Rupert now ranks as the 143rd richest person in the world according to the Bloomberg Billionaires Index, with a net worth exceeding $13.1 billion.

In recent days, Richemont’s shares have risen by 6.05 percent, jumping from CHF139.75 ($155.7) on April 6 to CHF148.25 ($165.17) at the time of this report.

The modest increase has driven the market value of Rupert’s 9.14-percent stake up by $420 million, elevating its total value to $9.82 billion.

With the latest increase in the company’s shares, Richemont’s stock price has now surged by over 16 percent since the start of the year thanks to its impressive sales figures at the end of the third quarter of its 2023 fiscal year.

The luxury goods group reported sales figures of over €15 billion ($16.3 billion) during this period, surpassing the first nine months of the 2022 fiscal year which saw €12.77 billion ($13.9 billion) in sales.

Notably, the surge was largely driven by a significant sales increase in Japan, rising from just under €855 million ($929 million) in 2022 to almost €1.29 billion ($1.4 billion).