He could not be contacted and telephone calls to his company's headquarters in Beijing rang unanswered.

Detention reported

Reports in the state-run newspaper 21st Century Business Herald and other mainland Chinese media said he was unreachable and had been detained, although Beijing police did not respond to phoned and faxed requests for comment.

"Wong Kwong-yu Board in Hiding," the Shanghai Securities News reported, noting that company officials refused to comment on the whereabouts of Wong and other top company executives.

The Securities Regulatory Commission in eastern China's Shandong province is investigating allegations of share manipulation involving Shandong Jintai, a medicine maker controlled by his brother, and will announce results soon, the website Sina.com cited a spokesman for the share watchdog's branch in Shandong as saying.

The spokesman said he could not comment on the allegations against Wong, who is also known as Huang Guangyu.

Fortune estimates

Calls to the Securities Regulatory Commission in Shandong rang unanswered Tuesday.

Estimates of Wong's fortune vary, though he recently topped a list of China's wealthiest individuals compiled by Shanghai-based analyst Rupert Hoogewerf, with assets said to be worth $6.3bn.

Trading in Gome's shares on the Hong Kong Stock Exchange was suspended as of Monday morning and the company issued a statement saying it was looking into reports of the investigation.

It said it had not received any legal notices concerning Wong's case.