Sprint said Monday it has reached a $2.2 billion deal to acquire the remaining shares it does not own in Clearwire, giving the number three US carrier valuable spectrum for expansion plans.
Sprint said in a statement it slightly boosted an offer announced last week, and that it would pay $2.97 per share. The deal values Clearwire at $5.5 billion.
Clearwire's board approved the transaction, Sprint said.
"Clearwire's spectrum, when combined with Sprint's, will provide Sprint with an enhanced spectrum portfolio that will strengthen its position and increase competitiveness in the US wireless industry," said a Sprint statement.
Sprint chief executive Dan Hesse said the deal "marks yet another significant step in Sprint's improved competitive position and ability to offer customers better products, more choices and better services."
Sprint, which is due to get a big capital injection from Japanese mobile carrier Softbank, gains control of Clearwire's spectrum and broadband WiMax network, which is becoming more valuable with the surge of mobile Internet use.
Softbank is set to acquire 70 percent of Sprint, the number three US carrier behind AT&T and Verizon Wireless, by the middle of next year.
Some minority shareholders in Clearwire have filed court action to block the deal, claiming Clearwire should seek a better offer.
Softbank agreed in October to pay $20 billion for a 70 percent stake in US-based Sprint in the biggest overseas acquisition by a Japanese firm.
The tie-up was expected to provide Sprint with capital that the company needs to compete better with its larger rivals, analysts said.
Sprint has around 56 million US customers, roughly half the size of Verizon and AT&T.
Adding Clearwire and its valuable spectrum could help Sprint, which is seeking to differentiate itself from its rivals by offering unlimited data packages for mobile phone users, according to analysts.