LINKEDIN’S STOCK NEARLY doubled in its market debut because of huge investor demand for the first major US social networking company to go public.

The stock traded at $87.11, up 94 per cent, this morning after debuting at $83 – and briefly reaching $92.99.

Renaissance Capital, an IPO research and investment firm, said LinkedIn’s 84 per cent increase at the open was the biggest for a US flotation since the 2009 debut of OpenTable, a restaurant reservations website.

IPO analyst Scott Sweet, the founder of IPO Boutique, credits the increase to LinkedIn selling a relatively small number of shares, 7.8 million.

Main Street investors clamored for the job networking site’s shares, which had only been available to the country’s biggest mutual funds, pension funds and other major institutional investors in an initial public offering yesterday.

LinkedIn’s IPO had been priced at $45 per share, at the high end of the company’s initial target. The company had raised $353 million on Wednesday night in an IPO that valued it at $4.3 billion – that’s the largest valuation for a public US Internet company since Google went public in 2004.

The company’s service helps businesses find new employees and promotes networking among the more than 102 million people that have set up profiles.

Sweet said the “monstrous interest” in LinkedIn and its sharp climb today were good signs for other social networking companies such as online messaging service Twitter, Web game maker Zynga, coupon site Groupon and Facebook.

LinkedIn is trading under the symbol “LNKD” on the New York Stock Exchange.

AP