A combination of Dish and T-Mobile would have an easier path to antitrust approval because it would keep four large wireless operators in the United States: Verizon Wireless, AT&T, Sprint and T-Mobile.
However, Dish would have less synergies with T-Mobile than Sprint, because it owns wireless spectrum but does not have a network or infrastructure. Dish has a market value of $25 billion while T-Mobile has a market value of $21 billion.
A merged Sprint and T-Mobile would be still smaller than market leaders Verizon and AT&T, but could run up against the government's previous stated stance that it wants to see four wireless players in the country.
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When the U.S. government blocked No. 2 wireless operator AT&T's proposed takeover of T-Mobile in 2011, antitrust regulators said that the market needed four national competitors.
The German operator, which owns 67 percent of T-Mobile, has been sounding out options to lessen the impact of the U.S. wireless business on its balance sheet for many years and even quietly discussed buying Sprint in 2008.
T-Mobile US was still struggling to compete at the time of its attempted merger with AT&T. But this year, the company has regained some ground with some unusual and competitive offers that appear to be winning over consumers and forcing bigger rivals to follow in its footsteps.
Dish's chairman Charlie Ergen has said that he wants to keep his options open as the company expands in the wireless space. Dish has been trying to acquire more spectrum in both bankruptcy and government auctions and has also said it is open to forging partnerships with other companies such as Sprint.
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Ergen, who founded Dish 33 years ago, has said he would look for ways to use wireless spectrum to enhance its video offerings rather than in areas such as voice, data and texting services where telecom companies have dominance.