WU XIAOHUI, 51

Anbang Insurance Group announced on Tuesday night that its chairman Wu Xiaohui was stepping aside "for personal reasons", hours after Chinese magazine Caijing reported that he was taken away by the authorities for investigation. The report was later erased.

GUO WENGUI, 50

A real estate tycoon who owns Beijing Zenith Holdings, Guo Wengui is facing a lawsuit over outstanding debts in New York, where he now lives after leaving China two years ago.

Guo, often said to be China's "most wanted man", has long been a thorn in the side of the Chinese Communist Party after unleashing corruption allegations against top Chinese officials on social media.

XIAO JIANHUA, 45

The Chinese-Canadian billionaire controls a sprawling empire with shares in banks, insurance companies, coal, cement and property through his Tomorrow Group. He was reportedly taken from a luxury Hong Kong hotel in a wheelchair in January and put in police custody to assist investigators in Beijing.

GUO GUANGCHANG, 50

Known as "China's Warren Buffett," Fosun International chairman Guo Guangchang went missing in December 2015.

He reappeared in the US later that month, allaying investor concerns that the Chinese authorities had restricted his movements.

Worth about US$6.9 billion (S$9.5 billion), Guo's investment group owns Club Med and Cirque du Soleil among other businesses.

BLOOMBERG, REUTERS, AGENCE FRANCE-PRESSE, NYTIMES