In addition to produce their own brands, dual-brand firms also supply private labels for particular retailers. Some leading Spanish brands such as Don Simón, Mahou and Carbonell, have been involved in this practice. Are these firms digging their own graves? The purpose of this study is to understand some reasons behind this phenomenon on Spanish retail market. we explored economical and relational motives of supplying store brands (SBs) by national brand (nB) manufacturers. our results suggest that dual-brand firms obtain: (1) better treat from retailers, (2) superior economies of scale and, (3) greater negotiation power.