Chinese equities open almost flat on Wednesday, a calm response to China's official launch of margin trading and short selling business.

The benchmark Shanghai Composite Index went up 0.04 percent to open at 3,129.57 points, and the Shenzhen Component Index rose 0.09 percent to 12,603.75 points.

Margin trading and short selling, starting on Wednesday, allows securities companies to lend stocks and money to investors for stock trading, which is expected to improve market efficiency.

Six securities companies, including CITIC Securities and Everbright Securities, have been approved to pilot margin trading business.

CITIC Securities rose 1.87 percent higher to open at 28.8 yuan.