Guo Guangchang, Executive Director and Chairman of Fosun International, who had been detained by police on corruption allegations, is helping with an investigation in China, said Fosun group.

Guo, known as China's Warren Buffett, is the chairman of China's largest private-sector conglomerate. His net worth, which is $5.6 billion, makes him the most high-profile business tycoon to be caught in the crackdown on corruption in China.

Trading of Fosun's shares were stopped in Hong Kong after he was detained, said Fosun in a statement. It is set to resume on Monday.

"The company understands that Mr Guo is currently assisting in certain investigations carried out by mainland judiciary authorities," the statement said.

"We are still in shock," South China Morning Post quoted a source at Fosun as saying  "Guo is very cautious in his handling of the government. As he often tells us, stay close to politics, but stay away from politicians."

Guo, the 17th richest person in China, has allegedly granted favours to an official at a state-owned company in China receiving benefits in return, reported The Guardian.

The annual meeting of Fosun is due to be held on Monday, where Guo was supposed to make a speech. 

The Chinese news portal also added that Guo was being investigated for allegedly being connected with the "discipline violation" investigation on former Shanghai deputy mayor and director of the Shanghai free trade zone Ai Baojun.

On 11 December, reports of Guo's disappearance were doing the rounds but it was later found that he had been taken into custody by the police.

After the Chinese stock market crashed, there has been a large scale crackdown on the financial sector. Recently, the securities regulatory commission of China has escalated investigations into local brokerage firms.

Fosun has assets in steel, pharmaceuticals, entertainment and real-estate. It also recently acquired real estate and made investments abroad.