This paper surveys recent work on competition in markets in which consumers face costs to switching between competing firms' products, even when all firms' products are functionally identical. I address issues in macroeconomics, international trade and industrial organization: In a market with...

What should be the West's top priority for climate-change policy? This article is a revised and updated version of my talk to the Potsdam Global Sustainability Symposium (which drafted the Potsdam Declaration presented to the 2007 UN Climate Change Conference in Bali).

Switching costs and network effects bind customers to vendors if products are incompatible, locking customers or even markets in to early choices. Lock-in hinders customers from changing suppliers in response to (predictable or unpredictable) changes in efficiency, and gives vendors lucrative ex...

Part ownership of a takeover target can help a bidder win a takeover auction, often at a low price. A bidder with a ‘toehold’ bids aggressively in a standard ascending auction because its offers are both bids for the remaining shares and asks for its own holdings. While the direct effect of...

Consider firms each selling a range of products, when each consumer prefers to concentrate his purchases with a single supplier because of the `shopping costs' of using additional suppliers. If the firms offer different product ranges, some consumers will nevertheless use multiple suppliers to...

We usually assume increases in supply, allocation by rationing, and exclusion of potential buyers will never raise prices. But all of these activities raise the expected price in an important set of cases when common-value assets are sold. Furthermore, when we make the assumptions needed to rule...

The most important issues in auction design are the traditional concerns of competition policy-preventing collusive, predatory, and entry deterring behaviour. Ascending and uniform-price auctions are particularly vulnerable to these problems (we discuss radiospectrum and football TV-rights...

We propose a new, easy-to-implement, class of payment rules, "Reference Rules," to make core-selecting package auctions more robust. Small, almost riskless, profitable deviations from "truthful bidding" are often easy for bidders to find under currently-used payment rules. Reference Rules...