In the retail sector, one of the main assets is shelf exposing space. However, most of the commercial applications available, as well as the procedures that retailers use to allocate space to products, are far from optimization purposes. Typically, retailers face two crucial decisions in order to attract customers: first, they have to define the assortment -which products to carry in the stores?-, then they have to organize the products’ facings -how many items for the same product to display in the front row?-. The outcome of these choices constitutes the marginality per exposing meter, that is a direct determinant for the profitability of a store.