Several mutually reinforcing trends have made category management (CM) one of the most critical marketing and operational decisions for retailers. German retailers and consumer goods producers recently rated “optimization of product portfolio and category management” the most important task for achieving performance goals (Breuer et al. 2009). This is not surprising as shelf space competition in retail stores is at an all-time high, driven by the competitive need to constantly introduce new products. There has been significant product proliferation since the 1990s (Greenhouse July 17, 2005). The average number of items in overall store assortments increased by 30% between 2000 and 2009 (EHI Retail Institute 2010). In confectionery, for example, the number of brands rose by more than 40% between 1997 and 2001, but overall volume by only 0.8% (Carlotti et al. 2006). Additionally, most retailers suffer from decreasing space productivity. Gutgeld et al. (2009) concluded that 19 out of 24 European retailers were unable to maintain their space productivity.