DealBook: How the iPhone Led to the Sale of T-Mobile USA

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.