The memo, reported by the Financial Times, also said that management had been in touch with the “backbone of our investment banking division”.
It added that “in such a critical moment, everyone must believe in the group, believe in the executive committee, and not lose our heads”, but acknowledged that “the available information is limited”.
China Renaissance said its board is not aware of any information to indicate that Mr Bao’s unavailability may be related to the company’s business or operations and it’s running normally under the executive committee.
In the Chinese business world, the phrase “out of contact” in many cases may mean that the person is under investigation by the authorities or assisting with some government investigation.
The well-known dealmaker’s disappearance is the latest in a series of cases of high-profile Chinese executives going missing following a major anti-corruption campaign launched by President Xi.
In 2015 alone, at least five executives became unreachable without prior notice to their companies, including Fosun Group Chairman Guo Guangchang, who Fosun later said was assisting with investigations regarding a personal matter.
Mr Bao has been absent from the office and other public venues for the last few days, according to local media reports.
Meanwhile Cong Lin, China Renaissance’s president, has been under investigation for months.
Mr Bao previously worked at Credit Suisse Group and Morgan Stanley and has been hailed as one of China’s best-connected bankers.
He was involved with major technology mergers including the tie-up of ride-hailing firms Didi and Kuaidi, as well as food delivery giants Meituan and Dianping.