According to his bank, billionaire technology dealmaker Bao Fan is working with Chinese investigators.
He vanished ten days ago, according to China Renaissance Holdings.
Top technology firms Didi and Meituan are among the clients of Mr. Bao, the CEO and founder of China Renaissance Holdings and a well-known deal broker in China.
Shares of the company have decreased by almost 30% since Mr. Bao vanished.
The bank informed the Hong Kong Stock Exchange in a filing that "the Board has become aware that Mr. Bao is currently cooperating in an investigation being carried out by certain authorities in the People's Republic of China.".
If and when the appropriate PRC authorities make a legitimate request, "The Company will duly cooperate and assist," it was added.
Although it did not provide specifics regarding the investigation, the announcement marks the first time China Renaissance has provided an explanation for the disappearance of its founder.
According to the Reuters news agency, authorities detained Mr. Bao earlier this month to help with a probe into a former coworker, Cong Lin, the former president of the company.
The disappearance of Mr. Bao occurs as Chinese authorities are targeting top technology firms with harsh measures.
Following remarks critical of market regulators, Alibaba founder Jack Ma vanished from view for three months in late 2020. He was scheduled to publicly list Ant Financial, a company that handles digital payments, which would have likely made him the richest man in China.
As part of Chinese President Xi Jinping's anti-corruption campaign, a number of high-profile Chinese executives have vanished, and Mr. Bao's disappearance follows in their footsteps.
At least five executives became inaccessible in just 2015, including Guo Guangchang, chairman of the Fosun Group. Later, the business claimed he was helping with inquiries regarding a personal matter.
Xiao Jianhua, a Chinese-Canadian businessman, was also detained in 2017. He was formerly one of the wealthiest people in China and was imprisoned for corruption last year.
Having carried out many of the transactions that have shaped China's online consumer economy, Mr. Bao is regarded as a titan in the country's tech sector. After working at Morgan Stanley and Credit Suisse in the banking industry, he founded China Renaissance in 2005.
In a 2018 article, Mr. Bao claimed that his business had "cross[ed] paths]" with 70% of the Chinese public's familiar internet companies.