An undertaking is defined as dominant if it enjoys such a significant market position as to grant it the power to behave, to an appreciable extent, independently of competitors, customers and ultimately consumers. This dominance lays a special responsibility on the undertaking not to hinder competition in the market. Sara Lembo at BonelliErede examines how the Treaty on the Functioning of the European Union (TFEU) prohibits a dominant undertaking from directly or indirectly imposing unfair prices.