CITIC Securities Co Ltd, China's largest publicly traded brokerage, is set to start bookbuilding for its up to $2 billion Hong Kong offering on Sept 16, according to a term sheet of the deal seen by Reuters on Sept 6.

The company has started pre-marketing the deal to investors on Sept 6 and expects to list the shares on the Hong Kong stock exchange on Oct 6, the term sheet said.

CITIC Securities' potential $2 billion initial public offering in Hong Kong is still pending official approval from the stock exchange there, China's top brokerage said late on Sept 5.

The Stock Exchange of Hong Kong (SEHK) had notified CITIC Securities that it had reviewed the Chinese brokerage's IPO application to issue up to 1.14 billion shares in Hong Kong, CITIC Securities said in a statement to the Shanghai Stock Exchange.

However, the notice does not constitute formal approval for its IPO plan and the SEHK still has the power to make further comments on its application, CITIC Securities said.