This paper analyses the profitability of horizontal mergers in a Stackelberg model and their impact on welfare when there is uncertainty about the marginal costs of the newly merged firms. The authors consider that the merging firms decide their production strategy knowing the actual value of...

Consider legal uncertainty as uncertainty about the legality of a specific action. In particular, suppose that the threshold of legality is uncertain. I show that this legal uncertainty raises welfare. Legal uncertainty changes deterrence in opposite directions. The probability of conviction...

Some path-breaking work on mergers takes efficiency gains for granted, or assumes that firms have perfect knowledge when taking merger decisions. In practice, firms and competition authorities cannot know exact future efficiency gains, prior to merger consummation. This paper analyzes horizontal...