An employee and a former employee of the China Securities Regulatory Commission (CSRC) are suspected of insider trading and forging official documents and seals, while a journalist and others are suspected of fabricating and spreading false securities and futures trading information, the agency said.
Read More Chinese regulator investigates share-dumping
In separate stock exchange statements posted late on Tuesday, four Chinese brokerages said the regulator was investigating them for failure to properly identify clients.
Haitong Securities, Founder Securities, Huatai Securities and GF Securities saw their share fall after they said the CSRC was looking for failures to review and verify client identity, in line with rules.
In July, the CSRC said it would investigate suspected market manipulation after Chinese stock market turmoil started around mid-June.