Alibaba Group Holding, to which Ant Group is affiliated, and exchange operator Hong Kong Exchanges and Clearing (HKEX) paced the gain after index compiler Hang Seng Indexes Co. announced plans to launch a gauge to track the biggest hi-tech stocks trading in the city next week. HKEX shot up 9.8 per cent for the biggest gain in five years, with trading volumes 63 per cent above the 20-day average. It closed at a record high of HK$380, bringing its year-to-date gain to 50 per cent.