Twitter prices above range to raise at least $1.8 billion

* Microblogging network prices 70 million shares at $26, above expected range

* IPO values Twitter at $14.1 billion, with potential to reach $14.4 bln

* Stock appears to have strong institutional support -analyst

By Olivia Oran and Gerry Shih

Nov 6 (Reuters) - Twitter Inc priced its initial public offering above its expected range to raise at least $1.8 billion, in a sign of strong investor demand for the most highly anticipated U.S. public float since Facebook Inc.

The microblogging network priced 70 million shares at $26, above the targeted range of $23 to $25, which had been raised once before.

The IPO values Twitter at $14.1 billion, with the potential to reach $14.4 billion if underwriters exercise an over-allotment option, as they are widely expected to.

If the full overallotment is exercised, Twitter could raise $2.1 billion, making it the second largest Internet offering in the U.S. behind Facebook's $16 billion IPO last year and ahead of Google Inc's 2004 IPO, according to Thomson Reuters data.

The focus now turns to how Twitter stock will fare on Thursday. Some analysts said they expect shares to experience a small pop during the first day. Twelve-month price targets on the stock range from $29 to $54.

Brian Wieser, an analyst at Pivotal Research Group who valued Twitter this week at $29 a share, said the stock appears to have strong institutional investor support and could easily close over $30 a share on its first day.

But he warned that trading could be volatile, given that Wall Street has struggled to value an unorthodox social media company with a newfangled business model.

"There's still so much uncertainty and it's so difficult to even identify how big the opportunity is," Wieser said. "Twitter will make Netflix look like General Electric as a bellwether of stability."

Investor enthusiasm for Twitter, which boasts 230 million users including heads of state and celebrities, is strong even though the microblogging network has never turned a profit.

Moshe Cohen, a professor at Columbia Business School in New York, said pressure on the company could quickly mount if shares lose steam out of the gate.

"Twitter, as a company with no expectations of making profits for several years, needs its investors to have faith," Cohen said. "If that stock starts to show some negative momentum from the beginning, it could last for a while."

Twitter, however, is listing amid the strongest market for U.S. IPOs since 2007, as equity markets soared and uncertainty around the U.S. debt ceiling has largely subsided for now.

A number of IPOs have doubled on their first day of trading, including Container Store Group, restaurant chain Potbelly Corp and software company Benefitfocus Inc .