Two years after AT&T's failed bid to acquire T-Mobile USA from German parent Deutsche Telekom, the telecommunications giant has once again turned to a team of lawyers from Sullivan & Cromwell, Arnold & Porter, and Crowell & Moring to advise on its proposed $1.19 billion cash buy of Leap Wireless, which is being advised by Wachtell, Lipton, Rosen & Katz.

AT&T announced on Friday that it has agreed to pay $15 a share for Leap, a prepaid cellphone service provider. That represents an 88 percent premium over Leap’s Friday closing price of $7.98 a share. The company’s stock soared on Monday to close at $16.95 a share.

San Diego–based Leap, which operates under the Cricket brand name, will give AT&T a stronger footprint in the prepaid market, where the company has been notably weak up until now. Leap's network covers about 96 million people in 35 states.

“The combined company will have the resources, scale, spectrum and network to better compete against other major national providers for consumers wanting a low-cost wireless plan,” said AT&T spokesman Brad Burns in a statement.

The deal must receive shareholder approval and is expected to close within the next six to nine months.

AT&T’s purchase of Leap follows a wave of mergers and acquisitions within the wireless world. On July 10 Japan’s Softbank Corp. bought a majority stake in Sprint Nextel Corp. for $21.6 billion, just days after Sprint bought Clearwire Corp. for $14 billion.

S&C advised AT&T on the Leap deal, reprising its role from 2011 when the firm represented the telecom on its failed bid to purchase T-Mobile for $39 billion. That deal, which would have reduced the market of major U.S. wireless providers to three from four, was ultimately abandoned in December 2011 after the U.S. Department of Justice successfully blocked the merger on antitrust grounds.

Compliance issues in the proposed T-Mobile transaction led AT&T to hire Arnold & Porter and Crowell & Moring for advice on regulatory matters. Both of those firms were again on hand for the Leap deal.

Partners Joe Frumkin and Eric Krautheimer, who cohead S&C’s M&A group, led the charge for Leap, with assistance from special counsel Lisa Murison as well as associates Georg Krause-Vilmar, Vanessa Pon, and Gideon Rov.

Frumkin and Krautheimer have both worked with AT&T on many other deals, including its sale to Cingular Wireless in October 2004 for $47 billion, its December 2006 acquisition of the BellSouth Corporation for $86 billion, and its sale of AT&T Advertising Solution and AT&T Interactive to a Cerberus Capital Management affiliate in May 2012 for $750 million.

Leading the team for Crowell & Moring is Randolph Smith, partner and cochair of the firm’s antitrust group. Firm spokeswoman Kathryn Holmes Johnson declined to name the other attorneys working with Smith on the deal.

The Arnold & Porter team advising AT&T on Federal Communications Commission regulations is led by antitrust and competition partners Richard Rosen and Wilson Mudge, along with telecommunications, Internet, and media partner Maureen Jeffreys.

Meanwhile, Leap has hired Wachtell for representation on the transaction, with Edward Herlihy and David Shapiro heading up the deal team that also includes corporate partner Gordon Moodie and associates Alison Zieske, Brett Shawn, and Minsun Lee. Also advising are executive compensation and benefits partner Jeannemarie O’Brien and associate Adam Kaminsky; restructuring and finance partner Joshua Feltman and associate Saish Setty; and tax partner Joshua Holmes.

Weil, Gotshal & Manges is representing Lazard as financial adviser to Leap in the deal, led by partner Howard Chatzinoff with assistance from associate Jenna Markowitz.