China Galaxy Securities Co rose as much as 11.3 percent in its trading debut on Wednesday after raising $1.1 billion in a Hong Kong IPO, underscoring a surge in retail investors' demand for new listings in the city.

The debut of China's seventh-biggest brokerage, and that of Sinopec Engineering (Group) Co Ltd on Thursday, will be bellwethers for a slew of Hong Kong offerings in the coming weeks.

China Galaxy shares jumped to HK$5.78 shortly after opening and traded as high as HK$5.90, up from the IPO pricing at exactly HK$5.30 per share.