The 39-year-old is legendary for his rags to riches story
Police have confirmed that one of China's richest men, Huang Guangyu, is being held in custody while they investigate him for "economic crimes".
Mr Huang went missing last week and shares in his company Gome have been suspended from trading.
Officials gave no further details, but Chinese media point to alleged irregularities in the share price of a company controlled by his brother.
The billionaire electrical appliance tycoon is worth some $6bn (£4bn).
"We can confirm for you the news that Wong is being held for investigation by Beijing police in connection with economic crimes," a police spokesman said, referring to Mr Huang by his other name Wong Kwong-yu.
It was the first official confirmation of widespread reports that the founder and chairman of Gome Electrical Appliances Holdings - which sells one in six of the electronic products bought in China - is being questioned for alleged share trading violations or other crimes.
Correspondents say the 39-year-old entrepreneur is something of a legendary figure, a living example of a rise from rags to riches.
The delay in official confirmation of Mr Huang's detention prompted a rare rebuke in a commentary carried on Xinhua, the official news agency.
The agency complained that in the face of many rumours, media questions had gone unanswered, prompting people to feel "lost".
The BBC's Chris Hogg says some in China see the investigation as an indication the authorities need to remind the country's tycoons who is really in charge, despite the former leader Deng Xiaoping's claim that to get rich is glorious.
The company says its operations are not affected by Mr Huang's situation, but has refused further comment.