We study a problem of optimal auction design in the realistic case in which the players can collude both on the way they play in the auction and on their participation decisions. Despite the fact that the principal's opportunities for extracting payments from the agents in such a situation are...

We analyze the performance of various communication protocols in a generalization of the Crawford-Sobel (1982) model of cheap talk that allows for multiple receivers. We find that whenever the sender can communicate informatively with both receivers by sending private messages, she can...

We solve for the optimal mechanism for selling two goods when the buyer's demand characteristics are unobservable. In the case of substitutable goods, the seller has an incentive to offer lotteries over goods in order to charge the buyers with large differences in the valuations a higher price...

We study communication in a static Cournot duopoly model under the assumption that the firms have unverifiable private information about their costs. We show that cheap talk between the firms cannot transmit any information. However, if the firms can communicate through a third party,...

We extend the 'no-haggling' result of Riley and Zeckhauser (1983) to the class of linear multiproduct monopoly problems when the buyer's valuations are smoothly distributed. In particular we show that there is no loss for the seller in optimizing over mechanisms such that all allocations belong...

We study cheap-talk pre-play communication in the static all-pay auctions. For the case of two bidders, all correlated and communication equilibria are payoff equivalent to the Nash equilibrium if there is no reserve price, or if it is commonly known that one bidder has a strictly higher value....