In a range of settings, private firms manage peer effects by sorting agents into different groups, be they schools, neighbourhoods or teams. This paper considers such a firm, which controls group entry by setting a series of anonymous prices. We show that private provision systematically leads...

This article studies the design of optimal mechanisms to regulate entry in natural oligopoly markets, assuming the regulator is unable to control the behavior of firms once they are in the market. We adapt the Clarke-Groves mechanism, characterize the optimal mechanism that maximizes the...

An important result in convex analysis is the duality between a closed convex set and its support function. We exploit this duality to develop a novel geometric approach to mechanism design. For a general class of social choice problems we characterize the feasible set, which is closed and...

I investigate the design of effort-maximizing mechanisms when agents have both private information and convex effort costs, and the designer has a fixed prize budget. I first demonstrate that it is always optimal for the designer to utilize a contest with as many participants as possible....

We show that if limit orders are required to vary smoothly, then strategic (Nash) equilibria of the double auction mechanism yield competitive (Walras) allocations. It is not necessary to have competitors on any side of any market: smooth trading is a substitute for price wars. Inparticular,...

We show that if limit orders are required to vary smoothly, then strategic (Nash) equilibria of the double auction mechanism yield competitive (Walras) allocations. It is not necessary to have competitors on any side of any market: smooth trading is a substitute for price wars. In particular,...

For an incomplete-information model of public-good provision with interim participation constraints, we show that efficient outcomes can be approximated, with approximately full surplus extraction, when there are many agents and each agent is informationally small. The result holds even if...

This paper studies optimal auction design when the seller can affect the buyers' valuations through an unobservable ex ante investment. The key insight is that the optimal mechanism may have the seller play a mixed investment strategy so as to create correlation between the otherwise...

A principal uses security bid auctions to award an incentive contract to one among several agents in the presence of hidden action and hidden information. Securities range from cash to equity and call options. "Steeper" securities are better surplus extractors that narrow the gap between the two...

This paper considers procurement auctions with costly bidding when the auctioneer is unable to commit himself to restrict the number of bidders. The auctioneer can, however, offer a financial reward to be paid to every short-listed bidders as an indirect commitment device. Rewards for...