Lens Technology Co, a Chinese mainland manufacturer of touch-screen covers for Apple Inc’s iPhone, rose in its Hong Kong trading debut after a HK$4.8 billion ($607 million) stock offering in the city.

The shares opened at HK$18.88 on Wednesday, up 3.9 percent from its listing, when they were sold at HK$18.18. The stock was priced at the high end of the marketed range, and attracted cornerstone investors such as Xiaomi Corp, UBS Asset Management AG and Oaktree Capital Management.  

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Lens Technology is the latest mainland-traded company to set its sights on the Hong Kong Special Administrative Region. Mainland companies have flocked to the city to list their shares amid a rally in the benchmark Hang Seng Index, which is forecast to double to more than $22 billion this year.

Lens Technology is the biggest debutant in what’s going to be the busiest day for share listings in Hong Kong this year. Wuhan Dazhong Dental Medical Co, Beijing Xunzhong Communication Technology Co, Beijing Geekplus Technology Co and Fortior Technology Shenzhen Co also begin trading in Hong Kong on Wednesday. 

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The company, which also makes other components for consumer electronics, saw sales and profit rise at least 20 percent last year, fueled by demand for smart gadgets. But Lens Technology remained heavily dependent on a few major clients, most notably Apple, which accounted for nearly half of its total sales.

“Lens Tech is one of the few global consumer electronics solution providers with advanced capabilities in both glass and metal processing,” SDICS International Securities analyst Alex Wang wrote in a note. Still, the company faces risks including “high customer concentration and intensifying industry competition,” according to the note.