De Beers is privately owned by Anglo American (85%) and the Botswana government (15%), so its shares are not traded on the stock market.[28] The Oppenheimer family had previously owned a 40% stake in De Beers, but this was sold to Anglo American plc in 2011.[29] Rio Tinto and BHP Billiton [citation needed] are the next largest producers, but diamond mining is a small part of their commodity portfolio.