(Telecompaper) T-Mobile US reported strong-than-expected customer growth in the fourth quarter and beat its full-year forecast for postpaid growth. The mobile operator added a net 2.1 million customers in Q4, for a total of just over 55 million, an increase of 17.9 percent year-on-year. In the retail postpaid market, T-Mobile gained 1.3 million new customers in the quarter and added over 1.0 million new phones to its network. For the full year 2014, the company reported the net addition of 4.9 million retail postpaid subscribers, better than its already improved guidance of 4.3-4.7 million. In Q4, the operator also added 266,000 prepaid customers, mainly under the MetroPCS brand, and 586,000 wholesale customers (152,000 in M2M and 434,000 at MVNOs). T-Mobile said the figures show it continues to win market share from its bigger rivals. The company gave figures for the postpaid porting market in Q4 showing it was winning 1.4 customers for every one lost to Verizon, 1.8 versus AT&T and 2.2 versus Sprint. Despite the strong increase in customers, T-Mobile said it was "managing the balance between growth and profitability". It did not give any profit figures, ahead of a full annual report in February.