Exchange members claim that the professional relationships that evolve on exchange floors yield benefits not easily duplicated by an anonymous exchange mechanism. We show that longstanding relationships between brokers and specialists can mitigate the effects of asymmetric information. Moreover, a specialist who actively attempts to differentiate between informed and uninformed traders can achieve equilibria that Pareto-dominate an equilibrium in which the two types of trades are pooled. Our model also elucidates the role of block trading houses in mitigating information problems in the block market.