There has been considerable debate concerning whether consumer surplus or total surplus should be the welfare standard for antitrust. This debate misses two critical issues. First, antitrust is not straightforwardly welfarist—it does not maximize but protects, and it does not forbid all...

We examine situations in which a party must make a sunk investment prior to contracting with a second party to purchase an essential complementary input. We study how the resulting old-up problem is affected by the seller’s information about the investing party’s likely returns...

Both senders and receivers of telecommunications messages derive benefits, creating the possibility of externalities. We explore whether intercarrier compensation (i.e., access charges) can induce carriers to internalize these external effects. In important settings, access charges are...

Many products—including microprocessors, telecommunications devices, computer software and on-line auction services—make use of multiple technologies, each of which is essential to make or sell the product. The owner of one technology benefits from the existence of complementary...

Intellectual property owners often hold the rights to several patents, each of which is essential to make or use a product. We compare the welfare properties of package licenses, under which a licensee pays the same fee regardless of the number of technologies licensed, with component licenses,...

We examine the welfare effects of product-line restrictions, such as those called for by some proponents of network neutrality regulation. We find that restricting a monopoly supplier to a single product has the following effects: (a) consumers who would otherwise have consumed a low-quality...

Three years ago, the Antitrust Division and the Federal Trade Commission revised their Horizontal Merger Guidelines to articulate in greater detail how they would treat claims of efficiencies associated with horizontal mergers: claims that are frequently made, as for instance in the recently...

We explore the logic of predation and rules designed to prevent it in markets subject to network effects. Although, as many have informally argued, predatory behavior is plausibly more likely to succeed in such markets, we find that it is particularly hard to intervene in network markets in ways...