This is a survey of the economic principles that underlie antitrust law and how those principles relate to competition policy. We address four core subject areas: market power, collusion, mergers between competitors, and monopolization. In each area, we select the most relevant portions of...

We propose a simple, new test for making an initial determination of whether a proposed merger between rivals is likely to reduce competition and thus lead to higher prices. Under current antitrust policy, the government can establish a presumption that a proposed horizontal merger will harm...

We consider a market in which firms can partially observe each consumer's search behavior in the market. In our main model, a firm knows whether a consumer is visiting it for the first time or whether she is returning after a previous visit. Firms have an incentive to offer a lower price on a...

There are many examples of markets involving two groups of participants who need to interact via intermediaries. Moreover, these intermediaries usually have to compete for business from both groups. Examples include academic publishing (where journals facilitate the interaction between authors...

This is a survey of the economic principles that underlie antitrust law and how those principles relate to competition policy. We address four core subject areas: market power, collusion, mergers between competitors, and monopolization. In each area, we select the most relevant portions of...

A common sales tactic is for a seller to encourage a potential customer to make her purchase decision quickly. We consider a market with sequential consumer search in which firms often encourage first-time visitors to buy immediately, either by making an "exploding offer" (which permits no...