According to All Things D, it has been confirmed that T-Mobile USA CEO Phillip Humm has resigned from the company, effective immediately. The company's statement goes on to further state that Humm will be leaving Deutsche Telekom (T-Mo's parent company) altogether, and that Chief Operating Officer Jim Alling act as Humm's interim replacement.

A statement from Deutsche Telekom Chief Executive Rene Obermann reads in part: “Philipp Humm has given the company some important initiatives over the past years: Under his leadership the cost situation at T-Mobile USA has vastly improved and he led the company during a difficult phase regarding the planned merger with AT&T.”

The Wall Street Journal adds that "Mr. Humm informed the company in April that he intended to leave at the end of September so he could return to his family in Europe. Mr. Humm's exit was sped up after he informed Mr. Obermann 'a few days ago' that he would be joining" an unnamed competitor.

Update: It looks like Geekwire got its hand on Obermann's letter.

Team,

I want you to hear the news directly from me: Philipp will be on leave with immediate effect. You might ask yourself, why I’ve taken this decision? Well, here is some background: In April, Philipp informed me that he intended to end his contract at the end of September.

During the merger process, we had agreed on such an option, just in case the merger did not materialize. Philipp told me back then that he wants to pursue a career outside of Deutsche Telekom and to reunite with his family, who have stayed in Europe. I decided back then to start the search for a successor. This search is progressing well. I have spoken to a number of promising candidates.

The reason Philipp has vacated his position with such short notice is because of his new employer: Philipp informed me a few days ago that he will be joining a competitor of Deutsche Telekom.

I have asked Jim Alling to lead the company until a final decision on a successor has been made. Jim is a respected senior leader who has my complete trust and confidence and that of the entire Deutsche Telekom Board of Management. Change of leadership has implications for both employees and the entire company, particularly when it comes to the period of transition. With this in mind, I would like to appeal to all of you to support Jim. I personally wish him the best of success.

I want to thank Philipp for his nearly two years with T-Mobile USA. His contribution to cost efficiencies and the development of the Challenger Strategy has given the company some important initiatives. With a new leader at the helm, our challenge will be to develop these initiatives into measurable success in the market.

I will be back in Seattle in mid-July to discuss next steps with the Management Team, including further business development.

In closing, I want to thank each and every one of you for your excellent work—particularly over the past few months. The successful upgrading of our network, building up our B2B business, re-launching the brand and the many other initiatives that we have started will bear fruit and will make us even more competitive.

Thank you and all the best,

René

René Obermann

CEO of Deutsche Telekom