The two largest wireless carriers, Verizon Wireless and AT&T, have been trying to bolster their spectrum holdings, while the next largest, Sprint and T-Mobile USA, have been seeking to make alliances to compete better. Here's a look at the merger and acquisition activity in the telecommunications industry over the past year:
— June 26, 2012: Verizon Wireless agrees to sell some airwave rights to T-Mobile and swap others.
— Aug. 2: AT&T Inc. announces three deals aimed at boosting its spectrum holdings. They are with Comcast Corp., NextWave Wireless Inc. and Horizon Wi-Com.
— Aug. 24: A consortium of cable companies sell their spectrum holdings to Verizon Wireless for $3.6 billion.
— Oct. 3: T-Mobile USA's parent company, Deutsche Telekom AG of Germany, agrees to buy MetroPCS Communications Inc. and merge T-Mobile into it.
— Oct. 11: Japan's Softbank Corp. agrees to pay $20.1 billion for 70 percent of Sprint Nextel Corp., providing a much-needed cash boost for the struggling carrier.
— Nov. 11: Sprint Nextel Corp. agrees to buy some U.S. Cellular Corp. service areas in the Midwest for $480 million.
— Dec. 13: Sprint agrees to buy out the minority shareholders of wireless network operator Clearwire Corp., of which it already owns a majority.
— Jan. 8, 2013: Dish Network Corp. offers to buy Clearwire for $5.15 billion, but Sprint says it's not willing to sell.
— Jan. 22: AT&T agrees to buy remnants of the Alltel network for $780 million.
— Jan. 25: Verizon Wireless agrees to sell some spectrum rights to AT&T for $1.9 billion and swap some others.
— April 11: T-Mobile USA sweetens the offer for MetroPCS after resistance from MetroPCS shareholders.
— Monday: Dish makes an offer for Sprint in an attempt to snag it away from Softbank. Dish offers $25.5 billion in cash and stock.