Guo Guangchang, chairman of Shanghai-based Fosun Group, China’s biggest privately held company, appeared early Monday at his company’s annual meeting after reports of his disappearance surfaced last week. The high-profile Chinese tycoon was first reported missing Friday.

Guo appeared at the Fosun event at the Kerry Hotel Pudong in eastern Shanghai where he discussed the company’s strategy and performance, but did not speak about his apparent disappearance, Reuters reported, citing a source. Photos of Guo at the event circulated on Chinese social media. Fosun said in a statement late Friday that Guo was assisting authorities in an unspecified investigation. Fosun President Wang Qunbin reportedly said the probe mostly concerned Guo's personal affairs, not company business, adding that no further details could be given out as the investigation was "sensitive."

Trading in Fosun’s Hong Kong-listed companies Fosun International and Shanghai Fosun Pharmaceutical was suspended at the firms’ request after Guo’s apparent disappearance. Companies owned by Fosun listed in Shanghai also suspended trading in their shares.

After resuming trade on Monday, Fosun's Hong Kong shares fell more than 10 percent. Shanghai Fosun Pharmaceutical shares also dropped over 4 percent.

Media speculation about the disappearance of Guo came amid the Chinese government's stringent anti-corruption campaign that has brought down several officials over the past three years, including Zhou Yongkang, China’s former security chief and a former member of the Communist Party’s ruling standing committee. A string of senior executives of Chinese companies have temporarily gone missing this year amid Beijing's crackdown on the financial sector.

Guo, 48, is China’s 11th richest person, according to Forbes China Rich List 2015, with personal assets of $6.9 billion. Often called "China’s Warren Buffett" for his aggressive and carefully planned investment strategy, Guo set up Fosun and began investing in pharmaceuticals soon after graduating from Shanghai’s Fudan University in the early 1990s. Fosun group recently took control of French holiday group Club Med in a deal worth some $1 billion.