The rate of convergence to perfect competition of matching and bargaining mechanisms

We study the steady state of a market with incoming cohorts of buyers and sellers who are matched pairwise and bargain under private information. We first consider generalized random-proposer take-it-or-leave-it offer games (GRP TIOLI games). This class of games includes a simple random-proposer TIOLI game, but also many other interesting bargaining games. A friction parameter is t , the length of the time period until the next meeting. We find that as t - O, all market equilibria converge to the Walrasian limit, at the fastest possible rate O(t) among all bargaining mechanisms. Some important bargaining games not in this class may have non-convergent market equilibria. This is the case for the k-double auction: we find that there are equilibria that converge at a linear rate, those that converge at a slower rate or even not converge at all.