New T-Mobile plan lets customers upgrade to a new phone up to twice yearly . Comment: In March , T-Mobile began offering some plans with no contract . Research firm comScore says Verizon has about 31 % of the market , followed by AT & T at 27 % , Sprint at 16 % and T-Mobile at about 13 % . It 's all part of a push by T-Mobile to move out of fourth place among U.S. carriers .
New T-Mobile plan lets customers upgrade to a new phone up to twice yearly . Comment: In March , T-Mobile began offering some plans with no contract . It 's all part of a push by T-Mobile to move out of fourth place among U.S. carriers .