HONG KONG (AP) — Shares of the company that operates one of China’s top investment banks, China Renaissance, plunged Friday after the firm said it had lost touch with its founder Bao Fan, one of the country's most high-profile bankers and a top tech-sector dealmaker.

China Renaissance Holdings said in a filing to Hong Kong's stock exchange Thursday that it had been unable to contact Bao, who has worked on major deals including e-commerce company JD.com’s $2 billion initial public offering and the public listing of short video platform Kuaishou in Hong Kong..

The company said that it was “not aware of any information that indicates Mr. Bao’s unavailability” was related to the business of the group.

Bao’s disappearance follows a crackdown on big technology companies in the past two years that officials in China said had been wrapped up.

Shares in China Renaissance fell as much as 50% Friday in Hong Kong. They were down about 28% in the afternoon.

China Renaissance did not immediately respond to emailed requests for comment Friday.

Bao’s disappearance comes months after former China Renaissance president Cong Lin was taken away by Chinese authorities in September last year, according to Chinese news media outlet Caixin, which first reported the news.

Anti-graft investigations in China targeting the financial sector have ensnared dozens of officials and finance executives at institutions such as Everbright Securities, China Construction Bank and major bank ICBC.

Bao earlier worked at Credit Suisse and Morgan Stanley. He founded China Renaissance in 2005 and took it public in 2018, raising $346 million.