De Beers Group is an international corporation that specialises in diamond exploration, diamond mining, diamond retail, diamond trading and industrial diamond manufacturing sectors. The company is currently active in open-pit, large-scale alluvial, coastal and deep sea mining. It operates in 35 countries and mining takes place in Botswana, Namibia, South Africa and Canada. Until the start of the 21st century, De Beers effectively had total control over the diamond market as a monopoly. Competition has since dismantled the complete monopoly, though the De Beers Group still sells approximately 35% of the world's rough diamond production through its global sightholder and auction sales businesses.The company was founded in 1888 by British businessman Cecil Rhodes, who was financed by the South African diamond magnate Alfred Beit and the London-based N M Rothschild & Sons bank. In 1926, Ernest Oppenheimer, an immigrant to Britain and later South Africa who had earlier founded mining company Anglo American plc with American financier J.P. Morgan, was elected to the board of De Beers. He built and consolidated the company's global monopoly over the diamond industry until his death in 1957. During this time, he was involved in a number of controversies, including price fixing and trust behaviour, and was accused of not releasing industrial diamonds for the U.S. war effort during World War II.In 2011, Anglo American took control of De Beers after buying the Oppenheimer's family stake of 40 percent for US$5.1 billion (£3.2 billion) and increasing its stake to 85 percent, ending the 80-year Oppenheimer control of the company. In 2018, De Beers became the first diamond company to announce that it would track its diamonds using blockchain technology, though this technology has not yet been rolled out.