Merged firms are typically rather complex organizations. Accordingly, merger has a more profound effect on the structure of a market than simply reducing the number of competitors. We show that this may render horizontal mergers profitable and welfare-improving even if costs are linear. The...

At the heart of antitrust law is the prohibition on horizontal collusion. To enforce this prohibition, the law must accurately define what collusion entails. One of the most controversial areas of antitrust is the issue of vertical restraints. In the last 20 years, economists have come up with...