Shares in investment holding company Camsing International crashed as much as 90 percent in Hong Kong on Monday, down 80 percent as of 2 p.m. local time, after revealing its chairwoman had been detained in Shanghai.

Hong Kong-listed Camsing told the territory's stock exchange late on Friday that 47-year old founder and chairwoman Lo Ching was "currently being held in criminal custody" by the Shanghai Public Security Bureau.

"The directors are unable to ascertain the reasons of, or incidents leading to, the criminal custody of Ms. Lo," the statement read.

It added that business and board operations haven't been adversely affected.

Lo is also chairwoman of Shanghai-listed Jiangsu Boxin Investing and Holding, which on Monday fell by the maximum 10 percent allowed.

Camsing in 2017 bought Pow! Entertainment, the company co-founded by Stan Lee, the late creator of superhero characters including Black Panther and Spider-Man.

News of Lo's arrest comes days after it emerged that Wang Zhenhua, the billionaire founder of property firm Future Land Development Holdings, had been taken into custody, sending the firm's share price tumbling 40 percent in three days.

(With input from AFP)