Christoph Achenbach, the head of the troubled German department store chain KarstadtQuelle, is resigning as a result of differences with other board members, sources close to the group's supervisory board said Thursday. Achenbach, appointed less than a year ago to turn the loss-making retailer around, has asked for his contract, scheduled to run until March 2006, to be terminated prematurely, sources said ahead of a key supervisory board meeting on Thursday. Rumors have been rife for weeks that Achenbach would step down and the 46-year-old no longer saw any basis for cooperation. A spokesman for KarstadtQuelle declined to comment on the information. If his contract is not renewed, Achenbach would see that as a vote of no confidence and step down. Should Achenbach quit, he will be the third chairman to throw in the towel at the company in just four years, dealing another severe blow to KarstadtQuelle, which is in the middle of a massive restructuring in an attempt to turn itself around. The group intends to sell off nearly half of its department stores, sell its specialist stores and cut around 5,500 jobs.