(Corrects 1st and 5th paragraphs and headline to make clear that PAR Capital is one of Orbitz's largest shareholders, not the largest)
Aug 13 (Reuters) - Orbitz Worldwide Inc said PAR Capital Management, one of its largest shareholders, sold 8.1 million of the 24.6 million shares it owned in the online travel agency, and the stock dropped 11.8 percent on Tuesday.
In a statement from Orbitz, PAR President Paul Reeder said the Boston investment management firm sold the shares in an effort to "better diversify our portfolio."
Reeder said PAR Capital was "optimistic" about the future of Orbitz, which last week reported second-quarter earnings that topped analysts' average estimates and raised its 2013 revenue outlook.
"We are especially excited about the accelerating growth that we are seeing in the company's hotel business," Reeder added.
PAR Capital had a 23 percent stake in Orbitz at the end of June, according to Orbitz data. The company's largest shareholder is Travelport, with a stake of 49 percent as of the end of the June, Orbitz said.
Shares of Orbitz were down $1.39 to $10.35 in morning trading. Even with Tuesday's slide, the shares have increased nearly fourfold so far this year. (Reporting by Karen Jacobs in Atlanta; Editing by Jeffrey Benkoe)