Head of T-Mobile USA Resigns Philipp Humm, chief executive of T-Mobile USA, has resigned from his position, Deutsche Telekom, the company that owns the carrier, said on Wednesday. The company said he planned to pursue a new career and spend more time with his family in Europe. Mr. Humm took the helm at T-Mobile USA in 2010. The carrier has been shedding subscribers and struggling to compete with competitors that have more popular devices, particularly the iPhone. Jim Alling, T-Mobile USA's chief operating officer, will be serving as the company's interim chief executive while it searches for a new leader, Deutsche Telecom said.