(Adds details about share ownership, share price update)
NEW YORK Dec 11 (Reuters) - Sprint Nextel Corp is in talks with Intel Corp and Comcast Corp to buy out their stakes in the U.S. wireless provider Clearwire Corp , two people familiar with the matter said on Tuesday.
The No. 3 U.S. cellular company, which owns just over 50 percent in Clearwire, would still need buy out the rest of the minority shareholders in Clearwire to gain full ownership.
Intel and Comcast own a combined basis roughly 12.4 percent of Clearwire's total shares outstanding, including publicly traded stock and Class B shares, according to a Clearwire filing.
Some minority Clearwire shareholders have publicly expressed concerns over a potential deal with Sprint, suggesting that Clearwire should look at other options.
Those shareholders include Mount Kellet Capital Management LP - the No. 2 holder of Clearwire's public shares with a 7.7 percent stake - and another top shareholder, Crest Financial Limited, which owns almost 7 percent, according to Thomson Reuters data.
Clearwire shares rose almost 12 percent on Tuesday after a CNBC report that Clearwire's majority shareholder, Sprint, was moving closer to a deal to buy the rest of the company.
Citing unnamed people close to the situation, CNBC said Sprint was in discussions to buy the 49 percent of Clearwire it does not already own and that a deal might be announced before the end of the year.
Sprint, which wants full ownership of Clearwire's wireless spectrum, has been in continuing negotiations with the company, but it is in no rush to finalize a deal, people familiar with the matter have told Reuters.
Consolidating the two companies' balance sheets could risk delaying the closing of Sprint's $20.1 billion deal with Softbank, a separate source close to the matter said.
While the timing of a Clearwire takeover is unclear, it had been planned for around the middle of next year, one of the people had said.
The people requested anonymity because the matter is not public. Sprint, Clearwire, Intel and Comcast all declined to comment.
Clearwire, whose biggest customer is also Sprint, has been looking to raise new financing as it could run out of money by the end of the third quarter of 2013.
Clearwire is also under pressure to move ahead with an upgrade of its network for high-speed wireless services.
CNBC reported that Sprint had been in talks in recent days with other Clearwire shareholders, which include Bright House, Intel and Comcast, to buy their shares of the company at about $3.00 each.
The report said that Sprint's offer price for the 488 million shares that are held by the public remained unclear.
Sprint has increased its ownership of Clearwire to 50.45 percent with the purchase of Eagle River Holdings' stake, which closed on Tuesday.
Clearwire shares closed up 11.67 percent at $2.68 on Nasdaq after the report, while Sprint fell 1.59 percent to $5.57. (Reporting By Nadia Damouni and Sinead Carew in New York; Noel Randewich in San Francisco; Editing by Soyoung Kim, Maureen Bavdek, Nick Zieminski, Lisa Von Ahn and Bernard Orr)