MICRO THEORY: Professor Siyang Xiong (University of California, Riverside)

When are simultaneous-bidding auctions without loss of generality?

When is it without loss of generality to study simultaneous-bidding auctions? Under Bayesian Nash equilibrium, Myerson (1981) implies always. Under obvious dominance (Li, 2017), sequential formats can implement outcomes that direct mechanisms cannot. We characterize the solution concepts for which every outcome implementable by a sequential-bidding auction admits an outcome-equivalent direct mechanism, and the complementary set for which sequential interaction is essential.