(Reuters) - Activist investor Carl Icahn disclosed a stake in Xerox Corp (>> Xerox Corp) and called the printer and copier maker's shares "undervalued," sending the stock up 7.6 percent in extended trade.

The billionaire revealed a 7.13 percent stake in Xerox in a securities filing on Monday, making him the second-largest shareholder of the 109-year-old company.

Icahn, who recently took stakes in American International Group (>> American International Group Inc) and Freeport-McMoran Inc (>> Freeport-McMoRan Inc), said he would look at getting representation on Xerox's board, as well as pursuing strategic alternatives.

"We are aware that Carl Icahn has made an investment in the company," Sean Collins, a Xerox spokesman said. "Xerox welcomes open communications with shareholders and values constructive dialogue."

Ivan Feinseth, a Tigress Financial Partners LLC analyst, offered a cautious view. "I like Icahn. He has done well but I just don't know what he can do here," Feinseth said.

On the other hand, Susquehanna Financial Group LLLP analyst James Friedman said there are multiple things that Icahn can push for in the company, including selling the equity stake in its joint venture Fuji Xerox and separating the Documents business and the IT services business.

Xerox's IT services business offers business process outsourcing while the document outsourcing business primarily includes sales of printers and copiers.

Friedman thinks Icahn can position himself for a board seat in the upcoming May elections.

"Getting on the board is the easy part, actually fixing the business is harder," Friedman said.

Susquehanna Financial has a valuation on Xerox of $13 per share based on a sum of the parts model, with $9 weighted on the documents business, $3 on the services business and the remaining on the Fuji Xerox business.

Xerox, whose shares have fallen more than 22 percent this year, is trying to turn itself around, shifting focus to software and services as corporate customers cut printing costs and consumers shift to mobile devices.

It reported its first quarterly net loss in five years in October, which prompted it to review its businesses and capital allocation options. The company, however, said it was not considering a sale.

Icahn has considerable success with spinoffs including the split of ebay Inc (>> eBay Inc) and Paypal Holdings Inc (>> Paypal Holdings Inc), and Manitowoc Company Inc's (>> Manitowoc Company Inc) separation of its crane manufacturing business from its food service business.

More recently, Icahn has been urging a breakup of American International Group (>> American International Group Inc).

Vanguard Group Inc, with an 8.37 percent stake, is Xerox's top shareholder, according to Thomson Reuters data.

(Reporting by Anya George Tharakan and Arathy S Nair in Bengaluru; Editing by Anil D'Silva, Siddharth Cavale and Leslie Adler)

By Arathy S Nair and Anya George Tharakan