Firms in the computer industry are often accused of vaporware, the untruthful pre-announcement of a new version of their product. By claiming they have a new product, critics argue, these firms try to deter potential entrants. The paper analyzes this phenomenon. It shows that vaporware is an...

We develop a method to screen for local cartels. We first test whether there is statistical evidence of clustering of outlets that score high on some characteristic that is consistent with collusive behavior. If so, we determine in a second step the most suspicious regions where further...