Robust double auction mechanisms

Abstract

We study the robust double auction mechanisms, that is, the double auction mechanisms that satisfy dominant strategy incentive compatibility, ex-post individual rationality, ex-post budget balance and feasibility. We first establish that the price in any deterministic robust mechanism does not depend on the valuations of the trading players. We next establish that, with the non-bossiness assumption, the price in any deterministic robust mechanism does not depend on players' valuations at all, whether trading or non-trading, i.e., the price is posted in advance. Our main result is a characterization result that, with the non-bossiness assumption along with other assumptions on the properties of the mechanism, the posted price mechanism with an exogenous rationing rule is the only deterministic robust double auction mechanism. We also show that, even without the non-bossiness assumption, it is quite difficult to find a reasonable robust double auction mechanism other than the posted price mechanism with rationing.