Hong Kong’s stock exchange had its busiest day of the year for new listings on Wednesday as five mainland Chinese companies made their debuts, cementing the city’s position atop the global ranking for initial public offerings (IPO). Wuhan Dazhong Dental Medical (2651) was the biggest winner of the day when its shares jumped 20 per cent at the open to HK$24, from its IPO price of HK$20. The shares of Apple supplier Lens Technology (6613) began trading at HK$18.88, a premium of 3.8 per cent from...