The chief operating officer of Bertelsmann has resigned to join UK private equity firm BC Partners, which was among the bidders for the German media group's music publishing arm BMG.

Ewald Walgenbach's departure follows the appointment of colleague Harmut Ostrowski to take on the role of chief executive at Bertelsmann. Walgenbach had been tipped as one of the favourites to succeed current chief executive Gunter Thielen at the beginning of next year.