Speaking to the Financial Times, Mr Stadler said there was "bias in the media" in reporting on billionaires. "In the talk of inequality, the debate that they are too greedy, that they make too much money on the back of poor people."
He said: "The data tells me that the debate is one-sided and it's a pity. There is a natural tendency today to be critical when it comes to wealth accumulation. There is sometimes a fear that there is a new aristocracy coming."
Mr Stadler also acknowledged criticism of multinationals over cross-border tax minimisation schemes. "This certainly needs to be closely watched," he said. UBS has been hit with billions of dollars in fines for helping rich clients evade taxes, including a €4.5bn penalty in France this year.
The stock market performance is boosted by the surge in valuations of billionaire-led technology companies, such as Facebook and Alphabet. The report shows that the billionaires' stock market success is clearest in the US, followed by China. Europe "has lagged behind slightly", yet billionaire companies still perform "significantly" better than the rest of the pack.
The report's methodology considers control to be 20 per cent of a company's equity or 30 per cent of a company's voting rights. That would exclude famous billionaire founders such as Jeff Bezos, who owns only 11.6 per cent of Amazon, but the report allows for exceptions where "the billionaire evidently steers the company".
Coming at a time when capitalism faces heavy criticism in the US and Europe, the report presents a stout defence of the world's top wealth creators in applying "new technologies and business models to change entire industries".
The authors argue that, while billionaires enrich themselves, they benefit the rest of society by generating jobs, creating wealth for others, including many employees, and paying tax.
Written by: Stefan Wagstyl
© Financial Times 2019