Until Apple introduced its highly popular touchscreen device in 2007, which went on to become the world’s leading smartphone, Deutsche Telekom had been generating decent sales from its American operation, with growth in some years surpassing that achieved in Germany. But after the iPhone went on sale, sold exclusively at first by AT&T in the United States, T-Mobile USA began to lose its most lucrative customers, those on fixed monthly plans, who defected to its larger American rivals — AT&T and Verizon Wireless, which began selling the iPhone in February. The percentage of T-Mobile USA’s contract customers fell to 78.3 percent in 2010 from 85 percent in 2006, according to the company’s annual reports. During 2010 alone, T-Mobile USA said it lost 390,000 contract customers to rivals.
While Nokia's growth has stalled, competitors like Apple and Android phone makers (Motorola, ZTE, HTC, etc.) have soared. Now the company is forced to make a big transition as it prepares to move away from the Symbian operating system to Microsoft's Windows Phone 7.