Economic theory does not provide sharp predictions on the welfare effects of banning wholesale price discrimination: if downstream costs differences exist then discrimination shifts production inefficiently; towards high cost retailers; so a ban increases welfare; if differences in price elasticity of demand across retailers exist; discrimination may increase welfare if more market is covered; so a ban reduces welfare. Using retail prices and quantities of coffee brands sold by German retailers; I estimate a model of demand and supply and separate cost and demand differences. Simulating a ban on wholesale price discrimination has positive welfare effects in this market; and less if downstream cost differences shrink; or with less competition.