The Chinese tech billionaire behind Asia's version of Amazon has reportedly not been seen in public for more than two months after falling foul of President Xi Jinping. Jack Ma, one of China's most successful and outspoken tycoons, criticised the country's 'pawnshop' financial regulators and state-owned banks in an incendiary speech in Shanghai in October. He called for reform of a system that 'stifled business innovation' and likened global banking ...