South African billionaire Nicky Oppenheimer has added $1 billion to his fortune in less than four months, extending a strong run in his wealth this year and lifting his net worth to $15.5 billion, according to the Bloomberg Billionaires Index.

Oppenheimer’s wealth has risen $1.65 billion since the start of the year, pushing him to No. 207 on the Bloomberg Billionaires Index. His fortune had already climbed from $12.9 billion on March 31 to $14.5 billion by May 7, extending a strong run of gains in 2026.

Oppenheimer’s investments beyond the diamond industry

The latest increase adds to a fortune built largely from the Oppenheimer family’s long association with the diamond industry.

In 2012, Oppenheimer and his family sold their 40 percent stake in De Beers to Anglo American for $5.2 billion, ending the family’s eight-decade involvement in the business.

Since then, the family has expanded its investments beyond diamonds. Oppenheimer co-founded Oppenheimer Generations, the family office he runs with his son, Jonathan Oppenheimer, with operations in Johannesburg and Singapore.

Jonathan has also built Oppenheimer Partners into an investment business focused on companies across Africa and other emerging markets.

Oppenheimer Partners’ growing investment portfolio

Earlier this month, Ghanaian energy company Genser Energy bought back the entire stake held by Oppenheimer Partners, ending the investment firm’s five-year involvement in the company. Genser said it redeemed the full shareholding previously held by OP Energy Holdings Limited.

Oppenheimer Partners has also invested in Nigeria’s consumer sector. In 2023, the firm acquired the remaining 37.5 percent stake in GZ Industries from Affirma Capital, giving it full ownership of the beverage-can manufacturer.

GZ Industries supplies cans to major beverage companies, including The Coca-Cola Company. The investment added to the Oppenheimer family’s holdings in African businesses outside the diamond industry.