Kirk Kerkorian is a corporate raider in the mould of Gordon Gekko, the fictional star of the 1987 film Wall Street who coined the phrase: "Greed is good."

So when the 87-year-old billionaire revealed on Wednesday that Tracinda, his investment company, had secretly built up a big stake in General Motors and was offering $868m to increase it to almost 9 per cent, investors were delighted.