HONG KONG: Camsing International Holding Ltd. tumbled a record 90% Monday morning in Hong Kong after the circuit-board maker said late Friday that chairwoman Lo Ching is in Chinese police custody.

In a statement to the stock exchange, Camsing said it became aware on July 5 that Lo was being held in criminal custody by the Yangpu branch of the Shanghai Public Security Bureau. The directors of the company were unaware of the reasons, the statement said, adding that business and board operations haven’t been adversely affected. 

Camsing didn’t immediately respond when reached for comment Monday.

Lo is also chairwoman of Jiangsu Boxin Investing & Holdings Co., which fell by the 10% daily limit in Shanghai for a second day. In a statement to the city’s stock exchange after Friday’s close, the company said Lo was taken into custody on June 20, while chief financial officer Jiang Shaoyang was detained on June 25. 

It said its business was operating as usual and that steps would be taken to enhance corporate governance.

Camsing shares were trading at the lowest since February 2015 and rooted to the bottom of the Hang Seng Composite Index, which was down 1.9% at 10:54 a.m. in Hong Kong. Trading volume was more than 200 times the 20-day average for this time of day, according to Bloomberg Automated Intelligence on Demand.

Another Hong Kong stock -- Future Land Development Holding Ltd. -- tumbled last week after a senior figure was detained by Chinese police. Such slumps can be particularly acute in China because the nation’s corporate founders play outsized roles.- Bloomberg