Shares of China Renaissance Holdings rose as much as 3.2 percent in early trade on Monday after the mainland boutique bank said its chairman, who it says had been missing, is cooperating with mainland authorities in an investigation.

Last week's disappearance of Bao Fan – a major figure in the tech industry and a key player in the emergence of various domestic internet startups – sent his company's share price plunging.

His Hong Kong-listed company said in a filing dated Sunday that it was now "aware that Mr Bao is currently cooperating in an investigation being carried out by certain authorities" on the mainland.

"The company will duly cooperate and assist with any lawful request from the relevant PRC authorities, if and when made.” The firm did not provide further details about the nature of the investigation.

China Renaissance has developed into a global financial institution, with more than 700 employees and offices in Beijing, Shanghai, Hong Kong, Singapore and New York. (Reuters/AFP)