A variance screen for collusion

In this paper, we examine price movements over time around the collapse of a bid-rigging conspiracy. While the mean decreased by 16%, the standard deviation increased by over 200%. We hypothesize that conspiracies in other industries would exhibit similar characteristics and search for “pockets” of low price variation as indicators of collusion in the retail gasoline industry in Louisville. We observe no such areas around Louisville in 1996-2002.