On September 18, 2008 the Bundeskartellamt launched an investigation into the alleged abuse of dominance by pay-TV operators Premiere, Kabel Deutschland and Unitymedia. Pay-TV customers in Germany are required to purchase set-top boxes that can be activated to receive the signal of a single provider. If the same customer moves to a location where the provider does not operate, he or she must buy a new set-top box. The authority will investigate whether such practices restrict competition in the pay-TV advertising market.