Competition and Collusion in Dealer Markets
构建博弈论模型分析做市商的跨期定价策略，发现非合作定价可能导致买卖价差高于竞争水平，这种隐性合谋不需要价格离散或信息不对称，而取决于限制订单流进入的制度安排。
ABSTRACT This article develops a game‐theoretic model to analyze market makers' intertemporal pricing strategies. We show that dealers who adopt noncooperative pricing strategies may set bid‐ask spreads above competitive levels. This form of “implicit collusion” differs from explicit collusion, where dealers cooperate to fix prices. Price discreteness or asymmetric information are not required for collusion to occur. Rather, institutional arrangements that restrict access to the order flow are important determinants of the ability to collude because they reduce dealers' incentives to compete on price. Public policy efforts to increase interdealer competition should focus on such restrictions.