* Prices 20 pct more shares than planned at top end of range
* Stock rally encouraging PE firms to exit investments
* This week could be heaviest IPO week since late 2007
By Olivia Oran
May 8 (Reuters) - Drug researcher Quintiles Transnational Holdings raised a more-than planned $947 million in its IPO, the latest listing from a private equity-backed company as record highs for U.S. stocks encourage more exits from investments.
Strong investor demand for the deal helped Quintiles, which is backed by Bain Capital LLC and TPG Capital LP, price 20 percent more shares than expected at the top end of the range and pushed up pricing a day early, according to people familiar with the deal.
Other public floats from private equity-backed companies this year have included Norwegian Cruise Line Holdings Ltd , SeaWorld Entertainment Inc, Pinnacle Foods Inc and Intelsat SA.
The Durham, North Carolina-based conductor of clinical trials is also the largest of eleven IPOs pricing this week, which could mark the highest weekly IPO volume since late 2007, according to market data firm Ipreo.
It priced 23.7 million shares at $40, compared with its plan to price 19.7 million shares at $36 to $40.
Other deals which have priced this week include residential mortgage company PennyMac Financial Services Inc and biotech company Receptos Inc.
Bain and TPG became the lead investors in Quintiles in January 2008 after One Equity Partners sold its stake in the company. Britain's 3i Group Plc and Singapore's Temasek Holdings are also investors in Quintiles.
Quintiles sold 13.1 million shares in the IPO. The company's founder and executive chairman Dennis Gillings and the private equity firms sold the remaining 10.6 million shares.
It will use IPO proceeds to pay outstanding debt, to terminate a management agreement with its private equity sponsors and for general corporate purposes.
Quintiles generated adjusted earnings before interest, tax, depreciation and amortization of $177.5 million on revenue of $4.9 billion in the year ended Dec. 31, 2012.
The company's rivals include Covance Inc, ICON and Parexel International, according to Morningstar.
Morgan Stanley, Barclays and JPMorgan are the lead underwriters on the offering.
Quintiles will list its shares on the New York Stock Exchange under the symbol Q.