The European Court of Justice’s definition of when a firm has a dominant position <p> has recently come under attack as being meaningless and impossible to measure. We argue that <p> both attacks are wrong, suggest an economic interpretation of domination and propose how it may <p> be measured using...</p></p></p>

I discuss the impact of tying, bundling, and loyalty/requirement rebates on consumer surplus in the affected markets. I show that the Chicago School Theory of a single monopoly surplus that justifies tying, bundling, and loyalty/requirement rebates on the basis of efficiency typically fails....

The challenge of effective merger enforcement is tremendous. U.S. antitrust agencies must, by statute, quickly forecast the competitive effects of mergers that occur in virtually every sector of the economy to determine if mergers can proceed. Surprisingly, given the complexity of the regulators...

Search engines face an interesting tradeoff in choosing the way to display their results. While providing high quality unpaid, or “left side” results attracts users, doing so can also cannibalize the revenue that comes from paid ads on the “right side”. This paper examines this tradeoff,...

I study Cournot competition under incomplete information about demand while assuming that market price must be non-negative for all demand realizations. Although this assumption is very natural, it has only rarely been made in the earlier literature. Yet it has important economic consequences:...

The controversy around the breakaway European Super League, set to conquer the UEFA Champions League, and the surrounding antitrust proceedings revive the academic discussion about the monopoly power of sport-internal governing bodies (like the UEFA), the justification for and limits of their...

We discuss the benefits of net neutrality regulation in the context of a two-sided market model in which platforms sell Internet access services to consumers and may set fees to content and applications providers on the other side of the Internet. When access is monopolized, we find that...

This paper studies an industry in which firms can choose to provide open or closed platforms. Open platforms, as opposed to closed, are extendable so third-party producers can develop extensions for them. Building on a two-sided market model, I show that firms might prefer to commit to keeping...

We compare four approaches to network neutrality and network management regulation in a two-sided market model: (i) no variations in Quality of Service and no price discrimination; (ii) variations in Quality of Service but no price discrimination; (iii) variations in Quality of Service and price...

This paper studies an industry where firms can choose to provide open or closed platforms. Open, as opposed to closed, platforms are extendable so that third-party producers can develop extensions for them. Building on a two-sided market model, I show that firms might prefer to commit to keeping...