Bellevue-based T-Mobile USA, the fourth largest wireless carrier in the U.S., reported 371,000 net customer additions during the fourth quarter as it boosted its 3G coverage across the country. That compared to net customer losses of 77,000 during the third quarter.

Even though the company added more customers, T-Mobile's service revenue declined to $4.65 billion in the fourth quarter due to an increase in wholesale customers. Total revenue also declined to $5.41 billion, down from $5.72 billion in the fourth quarter of 2008. And the average revenue per user at T-Mobile also dropped to $46.

The financial report comes amid additional speculation that T-Mobile's parent, Deutsche Telekom, might consider spinning off the company through an IPO.

A Deutsche Telekom spokesman confirmed that the company is talking to investment banks about a possible IPO, though the spokesman tells BusinessWeek that "we have to improve the operating performance to ensure a good IPO story.”

Analysts cited in the BusinessWeek report suggest that an IPO is likely, though one noted that the T-Mobile USA unit remains a "problem child."

The company served 33.8 million customers at the end of the fourth quarter, up from 33.4 million during the previous quarter and 32.8 million during the same period of 2008.

"T-Mobile USA made significant progress in 2009 in expanding its 3G network, improving its 3G-capable device lineup, enhancing its distribution, and underscoring its value proposition," said Deutsche Telekom CEO René Obermann in a statement. "This creates a solid foundation to benefit from the robust mobile Internet market."