Wireless carrier Sprint Nextel Corp has acquired voting control of Clearwire Corp after buying out one of the company's other shareholders, Sprint said in a securities filing on Thursday.

Sprint reached the deal with Eagle River Holdings on Wednesday and now controls a 50.8 percent stake in Clearwire, the filing said.

The Clearwire deal comes less than a week after Sprint agreed to sell 70 percent of itself to Japan's Softbank Corp in a $20 billion transaction.

Following that deal, analysts and investors widely expected Sprint to acquire or at least assume control of Clearwire, in which it already held a nearly 50 percent stake.

FBR Capital Markets, in a note to clients Thursday, said the deal eliminates a major risk for Sprint, in that it can now control Clearwire's valuable spectrum assets and ensure unfettered access to them.