Fosun International employees were unable to contact Guo Guangchang beginning at midday on Thursday, the magazine Caixin said on its website.
It cited what it said were messages on social media that Guo was last seen with police at an airport in Shanghai.
Guo's disappearance comes in the midst of a sweeping anti-corruption crackdown led by President Xi Jinping in which dozens of executives at state-owned companies have been detained or questioned. Businesspeople in previous investigations have been held for weeks for questioning with no public notice.
Fosun and its pharmaceutical unit suspended trading of their shares in Hong Kong. They cited the pending release of an announcement with "inside information."
Phone calls to Fosun's media and investor relations departments weren't answered.
Guo, 48, is one of China's biggest investors abroad. Fosun, which he co-founded in the 1990s, has businesses in real estate, steel, mining and retailing.
The Financial Times dubbed him "China's Warren Buffett" for following the legendary American investor's approach of using the cash flow from insurance operations to buy other businesses.
Fosun won a bidding war this year to take over Club Mediterranee, the French resort operator. Last year, it paid 1 billion euros ($A1.50 billion) for Portugal's biggest insurance company, Caixa Seguros.
In 2013, it bought the 60-storey tower at 1 Chase Manhattan Plaza in New York City for $725 million.
In the United States, it owns Meadowbrook Insurance Group Inc. and 20 per cent of insurer Ironshore Inc.
Guo had denied earlier he was the target of a graft investigation.
According to Caixin, a court in Shanghai said in August he had "inappropriate connections" with a former executive at several state companies, Wang Zongnan, who was sentenced to 18 years in jail on charges he misused corporate money.
