( CNN ) -- T-Mobile got aggressive in 2013 , positioning itself as the `` UnCarrier '' and actively courting customers of other mobile providers to switch . According to the company , it 's working -- at least in terms of adding new customers . The fourth-largest mobile carrier in the United States was also the fastest-growing in 2013 , adding 4.4 million customers , T-Mobile said Tuesday during a quarterly call with investors . `` What a year it 's been , '' CEO John Legere said . `` We 've been extremely busy . '' More than 1.6 million of those new customers arrived in the last three months of the 2013 fiscal year , marking the third quarter in a row that T-Mobile added more than 1 million paying users . But it was also the third quarter in a row that the company lost money : $ 20 million , this time . That reflects the money T-Mobile is spending to attract new users and expand its network , as well as some of the less-expensive plans it 's offering to lure all those new customers . Not surprisingly , Legere and other T-Mobile brass were n't emphasizing that part on Tuesday . Instead , they cited the growth numbers again and again . And they do mark a turnaround from the 256,000 customers T-Mobile lost in 2012 . Under Legere 's brash leadership , the company has taken some unconventional tacks to lure business . In January , T-Mobile offered to pay up to $ 650 towards customers ' early termination fees with other carriers if they switch . ( Of course , that was a response to AT & T targeting T-Mobile customers with a similar deal ) . It rolled out Jump , a program that lets customers upgrade phones twice a year for a small monthly fee , and announced new plans that do n't require an annual contract . And it did n't hurt that , last March , T-Mobile became an approved carrier for the iPhone for the first time . `` We changed the way this industry operates and customers responded , '' Legere said . While acknowledging that the highest number of customer defections came from AT & T , the No.1 carrier in the United States , T-Mobile declined to give more detailed figures . `` We 're not trying to be too cute about where the customers are coming from , '' Legere said . `` That 's not something we 're going to get into anymore . As ( mobile carriers ) are all getting highly competitive , we 're not going to give a further road map of where they 're coming from . '' T-Mobile also expanded its 4G LTE network in 2013 . It now covers 209 million people and is in 95 of the top 100 metro areas in the U.S . The company has plans to further expand in 2014 , eventually covering more than 250 million potential customers .
T - Mobile added 4.4 million subscribers in 2013 . Its ` ` UnCarrier '' approach targets customers of other brands . Company still makes money , though : $ 100 million last year . 2013 saw T - Mobile offer no - contract service , add services and expand network .