American TV mogul Oprah Winfrey and newcomer Isabel dos Santos of Angola are the only black female billionaires on the FORBES billionaires list.

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According to Forbes, Isabel Dos Santos is the biggest shareholder in Zon Multimedia, the biggest cable TV operator in Portugal, owning a 28.8% stake.

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The No. 1 wealth-producing industry: Investments, which made 148 billionaires including George Soros, Carl Icahn and newcomers Seth Klarman and Isabel dos Santos.

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His eldest daughter Isabel dos Santos is regularly cited as one of the most influential businesswomen in Portugal, where she holds shares in energy, telecomms and financial companies.

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In fact, the No. 1 wealth-producing industry is Investments, where 148 billionaires including George Soros, Carl Icahn and newcomers Seth Klarman and Isabel dos Santos derive their wealth.

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Over the past few years Isabel dos Santos, the oldest daughter of Angolan President Jose Eduardo Dos Santos, has been buying more shares of publicly traded companies in Portugal, including shares in a bank and a cable TV company.

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