From the viewpoint of competition policy the question should be answered whether we have effective competition between Aral, Shell, Esso, Total, and Jet (Oligopoly with 5) and with fringe gasoline stations. Following an inquiry of the German Cartel Office between 2007–2010 we are using Market Transparency second based price data out of 2014 in four German metropolises, and we have evidence that Aral and Shell are charging high prices, little bit lower prices in case of Esso and Total; Jet and fringe gasoline stations are working with lower prices. In morning hours all stations are starting with high prices, decreasing price during the day are following and reaching lowest prices in early evening hours. The oligopoly without Jet always increase prices shortly after 6 p.m., Jet always follows two and half hours later. All of the stations will be back to the starting price level at latest in midnight. Using multivariate estimations Shell reacts one to one on price increases started by Aral, perhaps a little bit stronger; fringe firms also react on Aral price starts, but with a lower magnitude. Aral and Jet show weaker reactions in case of price starts of Shell. Stable, but brand specific patterns of price increasing are strong evidence for collusive behaviour according section 18, V of the German competition law. But the legal assumption of market power (sec. 18 VI) should not be based on the fact that Jet is part of the gasoline oligopoly in Germany.