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The public stock portfolio of South African billionaire Nicky Oppenheimer's family returned close to 25% in dollar terms in 2025, according to the latest accounts of Stockdale Street Ltd., the London firm that invests the family's money.
Stockdale Street manages the global investments of two branches of the Oppenheimer dynasty, which controlled diamond producer De Beers for most of the 20th century. One is Nicky Oppenheimer and his son Jonathan, who run their interests through Oppenheimer Generations. The other is Nicky's sister, Mary Slack, and her daughters, known as the MOD family. Each side owns half of the firm.
Every asset class in the family's global portfolio made money last year, the firm said. Stocks did best, and real estate and credit also had a strong year. Stockdale Street said a venture capital portfolio it is building "continues to grow and shows encouraging signs for the future," and that the funds it oversees mostly beat or matched their benchmarks. Assets under management rose in sterling terms.
Nicky Oppenheimer is one of Africa's richest people, with a fortune built largely on the $5.1 billion his family received when it sold its 40% stake in De Beers to Anglo American Plc in 2012.
Fees and profit
The firm earns its money from fees paid by the families it serves, much of it set under transfer pricing agreements that cover its costs. Fees came to £9.69 million ($12.8 million) last year, almost unchanged from £9.76 million in 2024.
Two family vehicles account for more than 90% of that. EOSon Investments M Ltd. paid £4.58 million ($6.06 million) and EOSon Investments N Ltd. paid £4.22 million ($5.58 million). Fees from the Brenthurst group of private equity funds, also run for the family's benefit, fell by half to £821,335 ($1.09 million).
Profit after tax dropped 26% to £1.87 million ($2.48 million), mainly because of higher staff and administrative costs tied to its U.S. office. Administrative expenses rose 13% to £7.34 million ($9.7 million).
Stockdale Street paid £3 million ($3.97 million) in dividends to its two family shareholders, up from £2.5 million a year earlier. It ended the year with £5.92 million ($7.83 million) of cash and no borrowings.
A small, well-paid team
The firm employs very few people. It had an average of 14 staff in 2025, six in investment management and eight in administration, up from 12 a year earlier. The increase came at its U.S. subsidiary, Stockdale Street (USA) Inc., which now has two investment staff.
Staff costs, including directors, totaled £4.72 million ($6.25 million). Its four directors earned £2.57 million ($3.4 million) between them, and the highest paid received £1.25 million ($1.65 million).
The model is deliberately lean. Stockdale Street says it invests across asset classes worldwide by backing a small number of outside managers it considers "generational," and co-investing alongside them, rather than building a large in-house team. Its focus is on "compounding equity value in high-quality businesses for the long-term."
It adds and drops managers selectively and said it has no plans to change its business model.
The family behind it
The ultimate owners of Stockdale Street are Bermuda-based trustee companies acting for a set of family trusts. On the MOD side, they include the Mary Slack 2020 Sole Benefit Trust and separate trusts for her daughters Rachel Slack, Rebecca Oppenheimer, Jessica Slack Jell and Victoria Freudenheim. On the other side are the Nicky Oppenheimer 2006 Sole Benefit Trust and the Nicky Oppenheimer 2006 Discretionary Trust.
Nicky Oppenheimer, 81, is the grandson of Ernest Oppenheimer, who founded Anglo American in 1917 and took control of De Beers in 1929. He was chairman of De Beers until the family sold out. Mary Slack is the daughter of the late Harry Oppenheimer, who ran both companies for decades.
Since the De Beers sale, the family has spread its money well beyond mining. Oppenheimer Generations, chaired by Nicky and run by Jonathan as executive chairman, holds stakes in businesses across Africa and owns Tswalu Kalahari, South Africa's largest private game reserve.
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