Best Buy CEO Brian Dunn has resigned after a three year run, and it appears to be an amicable split: Best Buy's board of directors says there was "mutual agreement" on the decision, and that it didn't disagree with Dunn and the company on its management. The board has selected G. Mike Mikan as an interim CEO, and says that it is "time for new leadership to address the challenges that face the company." And Best Buy's challenges are substantial — the company posted a $1.7 billion quarterly loss in its fiscal fourth quarter 2012, and announced recently that it plans to close 50 US stores as part of a cost-saving restructuring effort. The end of the road for Dunn at Best Buy comes after 28 years with the company and a start as a salesman.

Dunn's interim successor says that he will be "extremely focused on successfully managing this period of transition," that will shed the company's retail footprint in the US by 20 percent, and cut a number of staff from Best Buy's corporate headquarters. The move is intended to save Best Buy $800 million in costs, but it's not yet clear how the company plans on competing with internet giants like Amazon that have squeezed big box retailers with fierce competition.

Update: The Star Tribune reports that Dunn's departure occurred directly following a personal misconduct investigation. A spokesperson for the company tells the Star Tribune that "certain issues were brought to the board's attention regarding Mr. Dunn's personal conduct, unrelated to the company's operations or financial controls." Dunn is said to have resigned before the investigation's completion.

Thanks, steffmn!