The German Cartel Offi ce's recent study of retail gasoline markets provides strong evidence of an oligopoly in which the major suppliers coordinate pricing strategies and achieve supracompetitive prices. Competition law enforcement does not provide effective tools to improve market outcomes. We examine the potential benefits of a regulatory framework that would require gasoline suppliers to announce at a specified time their prices for the following day and prohibit price changes during a 24-hour period. Such a 24-hour rule could complicate coordination and lead to lower prices, although it cannot be ruled out that the oligopolists would adjust and develop new coordination strategies.