Deutsche Telekom is mulling options for its T-Mobile USA unit, including an initial public offering or spinoff, sources familiar with the company's thinking told Reuters on Friday. 

The sources said Deutsche Telekom had held initial talks with banks but no formal process was underway and an IPO was only one of several options, after the Wall Street Journal reported that Deutsche Telekom was preparing an IPO or spinoff. Other possibilities include a sale, organic expansion or a partnership with another operator. 

Deutsche Telekom has been searching for the right strategy for T-Mobile USA, once prized as its growth engine. But the unit has struggled to build scale and has been losing customers. This has led to pressure from shareholders including private equity group Blackstone and the German government for Deutsche Telekom to resolve the problem. 

The Wall Street Journal said the most likely IPO scenario would be a sale of 20 percent of T-Mobile USA. The United States is Deutsche Telekom's biggest market outside Germany and brings in about a quarter of the company's revenue. T-Mobile USA ranks fourth in the U.S. market behind Verizon Wireless, AT&T Inc and Sprint Nextel Corp.