CITIC Securities , China's biggest listed brokerage, estimated on Tuesday that net profit in the first half of this year rose more than 5.5 times from a year earlier.

The company cited a strong Chinese stock market and heavy trading turnover. In the first half of last year, CITIC Securities posted a net profit of 628 million yuan ($83 million).

The brokerage is due to announce official, detailed first-half earnings on Aug. 15. Listed companies that expect to report changes of more than 50 percent in earnings are required to make public statements before the official release date. ($1 = 7.56 yuan)