We analyze the efficiency defense in merger control. First, we show that the relationship between exogenous efficiency gains and social welfare can be non-monotone. Second, we consider both endogenous mergers and endogenous efficiencies and find that merger proposals are largely aligned with a...

We analyze horizontal mergers when the acquirer holds a passive partial ownership stake (PPO) in the target firm prior to the merger. We show that a PPO reduces the minimal synergy level necessary to make a merger beneficial for consumers. It follows that an antitrust authority ignoring existing...

This paper offers a new and broad insight into the landscape of German cartels, utilizing a unique dataset of all illegal horizontal cartels detected by the German Federal Cartel Office (FCO) between 1958 and 2004 and all legal cartels authorized during the same time period. We also provide the...