* IPO priced at HK$20.60/share, top of marketing range-sources
* Proceeds to help pay outstanding loans, expand two facilities
* Stock to debut on June 13 (Adds HK IPO activity, WuXi IPO demand, comments)
By Julie Zhu and Elzio Barreto
HONG KONG, June 6 (Reuters) - WuXi Biologics (Cayman) Inc priced its Hong Kong IPO at the top of expectations on Tuesday, raising $511 million in the largest new listing in the Asian financial hub in 2017, as investors jostled for a piece of the fast-growing business.
The Chinese contract drug research and development company priced the 193 million shares on offer at HK$20.60 each, sources with direct knowledge of the deal said, the top of its marketing range of HK$18.60 to HK$20.60 per share. The price would value the deal at HK$3.98 billion ($511 million).
The deal will provide a much needed boost to IPO activity in Hong Kong, which has fallen by almost 50 percent from the same period in 2016 to $2.76 billion, the slowest start of a year since 2012.
The IPO was more than 30 times subscribed, underscoring investors' appetite for a sector with a "rarity appeal", and for a company whose revenue jumped 77 percent in 2016 from the previous year. Profit more than tripled last year as it expanded the business and launched new projects.
"The reason this deal is so popular is because we don't have other similar biotech companies listed in Hong Kong and WuXi Biologics itself has been performing quite well in recent years, which in turn has made investors more comfortable," one of the sources said.
The sources declined to be named because details of the initial public offering were not yet public. WuXi Biologics did not reply to a Reuters request for comment.
The shares will debut on the Hong Kong stock exchange on June 13.
WuXi Biologics, which does work for pharmaceutical and biotechnology firms, plans to use about 45 percent of the IPO proceeds to pay all its outstanding loans and debt and another 45 percent to expand its facilities in Shanghai and in nearby Wuxi in Eastern China, the company said in the prospectus.
The remaining 10 percent would be used for working capital.
Bank of America Merrill Lynch, China Merchants Securities and Morgan Stanley acted as joint sponsors and joint bookrunners of the IPO, according to the prospectus.
The banks stand to jointly earn about $17.9 million in fees, equivalent to a 2.5 percent underwriting commission and a 1 percent incentive fee, according to the prospectus.
WuXi Biologics parent, WuXi Pharmatech, was among several Chinese companies that delisted from U.S. exchanges in 2015 seeking better valuations closer to their home market. The company's $3.6 billion take-private deal was among the biggest at the time. (Reporting by Julie Zhu; Writing by Elzio Barreto; Editing by Stephen Coates)