UPDATE, 10/19/12, 5:35 p.m. EDT: The eleventh paragraph of this article has been updated to reflect the fact that Gary Friedman confirmed the role of Freidman Kaplan Seiler & Adelman in this transaction to The Am Law Daily.

Sprint Nextel is moving to take control of wireless network operator Clearwire Corporation by buying the Clearwire stake now held by company founder Craig McCaw’s Eagle River Holdings, according to regulatory documents filed Thursday.

Sprint said in a Securities and Exchange Commission filing that it will pay roughly $100 million to increase its stake in Bellevue, Washington–based Clearwire from 48.15 percent to 50.8 percent.

Overland Park, Kansas–based Sprint is already Clearwire’s largest shareholder. But, as The New York Times notes, gaining a controlling interest in the company will give the wireless carrier a greater say in Clearwire’s operations as it expands its high-speed LTE wireless network in the United States. Sprint originally acquired a majority interest in Clearwire in 2008, but has reduced its stake in the company since then.

The Washington Post reports that the terms of the agreement between Sprint and Eagle River also gives other major Clearwire investors—including Comcast Corporation, Bright House Networks, and Intel Corporation—the option of buying a portion of McCaw’s shares. Even if those investors fully exercise their options, Sprint will still hold at least a 50.02 percent stake in the company.

The deal comes on the heels of the transaction announced earlier this week under which Japanese telecommunications company SoftBank has agreed to buy a 70 percent stake in Sprint for $20.1 billion. That deal is expected to close in the middle of next year, assuming shareholder and regulatory approvals can be obtained, according to sibling publication The Asian Lawyer. Sprint and SoftBank may eventually decide to buy Clearwire in its entirety, as the latter company’s management looks to expand Sprint’s high-speed coverage in order to better compete in the U.S. with rivals Verizon Wireless and AT&T, according to the Times. (The Asian Lawyer has more on the Morrison & Foerster lawyers who advised SoftBank in connection with the agreement with Sprint.)

The Washington Post notes that while Sprint’s past financial struggles have prevented it from fully investing in Clearwire’s growing high-speed network, the infusion of SoftBank capital has changed the equation. The price of Clearwire shares nearly doubled after the announcement of Sprint’s deal with SoftBank.

For representation on the deal with Eagle River, Sprint turned to King & Spalding M&A cohead—and frequent counsel—Michael Egan, who is leading a team from the firm that also includes fellow M&A cohead E. William Bates II. Both partners were part of the King & Spalding team that advised Sprint four years ago on the $14.5 billion venture with Clearwire that resulted in the carrier taking its original stake in the company.  

Charles Wunsch is Sprint’s general counsel.

Kirkland & Ellis and Davis Wright Tremaine advised Clearwire on the 2008 deal with Sprint. Neither firm immediately responded to The Am Law Daily‘s requests for comment on whether they were involved in the agreement made public Thursday.

Clearwire’s general counsel, Broady Hodder, is a former Davis Wright partner.

Meanwhile, Gary Friedman, a corporate partner with New York’s Friedman Kaplan Seiler & Adelman, is advising Eagle River on corporate and securities aspects of the deal.

A separate SEC filing submitted Thursday identifies outside counsel for several of Clearwire’s biggest investors. According to the filing, Gibson, Dunn & Crutcher corporate partner Gregory Davidson and tax partner Paul Issler are advising Intel; Sabin Bermant & Gould telecommunications law partner Arthur Steinhauer is representing Bright House Networks; and Davis Polk & Wardwell M&A partner David Caplan is advising Comcast.