Cross-Subsidization in Checking Accounts: Note
应用Wilson的保险市场模型分析商业银行支票账户市场，发现信息不对称导致定期支票账户长期补贴特殊支票账户，并用数据验证了这一异常均衡的存在。
Incomplete and asymmetric information has in recent years been shown to create a number of anomalies in the operation of markets. Wilson (1977) has shown that insurance markets in such circumstances may lack a stable equilibrium unless the producing firms have sophisticated expectations and strategies. Miyazaki (1977), applying similar analysis to labor markets, establishes that equilsbrium under asymmetric information may entail persistent cross-subsidization within a firm of unprofitable contracts by profitable ones. Such analysis has hitherto confined itself to the theoretical realm. This paper applies Wilson's model to the market for checking accounts at commercial banks, thereby demonstrating the theoretical expectation of an anomalous equilibrium, and then examines data for evidence of such anomalies in practice. Our empirical investigation reveals that regular checking accounts have persistently subsidized socalled checking accountsl over the last decade and that other conditions of the model are met. In accounting for the coexistence of the two types of accounts and the crosssubsidization between them, we must first introduce some background information. Check processing costs account for a substantial portion of the total checking account expenses for commercial banks. For example, for banks with assets above $200 million in 1977, this share ranged from 43 percent on special checking accounts to 67 percent on regular accounts.2 Since different depositors write checks more or less frequently, each depositor will cost the bank different amounts to maintain his account. We might ordinarily expect competitive forces in the market to respond to this