(Telecompaper) US mobile operator Sprint said it expects a return to underlying profit growth in 2012, after a continued deterioration in results in 2012. The company forecast adjusted OIBDA of 5.2-5.5 billion in 2013, after the 2012 result fell to USD 4.8 billion from USD 5.0 billion in 2011. Sprint's net loss for 2012 swelled to USD 4.3 billion, including USD 1.3 billion in Q4 alone, due to the costs of shutting down the Nextel CDMA network as well as launching the iPhone. The extra investments in launching its LTE network and new phones and services led to a 5 percent increase in group revenues over the full year to USD 35.3 billion. Mobile service revenues improved 12.2 percent year-on-year in Q4 on the Sprint platform, and the Sprint customer base rose by 683,000 in the three months to 53.54 million. However, with only about 50 percent of Nextel customers converted to Sprint, the operator had a net outflow of 337,000 customers in the quarter, and a total base of 55.63 million customers. Postpaid ARPU increased slightly from Q3, to USD 61.47. Sprint finished the year with USD 8.2 billion in cash and said it has also received USD 3.1 billion from SoftBank in a 1 percent, seven-year convertible bond related to the Japanese operator's pending takeover of Sprint. After an increase in capex to USD 1.9 billion in the fourth quarter, free cash flow was a negative USD 1.3 billion.