Allan Gray, founder of Bermuda–based Orbis Investment Management, may not be a household name in the United States, but the South Africa native is one of the world’s most successful managers, with a career spanning half a century. Gray has turned Orbis’s initial $67 million in assets under management into $30 billion since 1989 and has opened eight offices worldwide. His son, CIO William Gray, who joined the global equity firm in 1993, now runs Orbis Investment Management while Gray stays on as chairman. Orbis’ most successful fund within its hedge fund business is its flagship Global Equity Fund…