Alibaba's U.S. shares sank more than 15% during the day. "The antitrust investigation into Alibaba has yet to specify the penalties, which is worrying investors a lot," said Zhang Zihua, chief investment officer of Beijing Yunyi Asset, adding a probe outcome could "greatly change" the company valuations. Putting investors more on edge was news over the weekend that China's central bank had asked Ant to shake up its lending and other consumer finance operations. These developments are part of a crackdown on monopolistic behaviour in China's booming internet space in general, but Ma's business empire in particular after he publicly criticized the regulatory system for stifling innovation. Last month, Chinese regulators abruptly suspended Ant's blockbuster $37 billion initial public offering in Shanghai and Hong Kong, which was on track to be the world's largest, just two days before its planned debut.