Previous analyses of the economic effects of deposit market deregulation generally have treated the gradual elimination of deposit rate ceilings and the effective removal of barriers to bank competition for deposits as separate issues. The key implication of the analysis utilized in this paper is that there are important interactions between these two forms of deposit market deregulation and their ultimate effects on market behavior and outcomes. One aspect of this interaction concerns the payment of implicit interest on deposit balances. Although implicit interest payments usually are viewed as a response to the imposition of ceilings on explicit deposit rates, the amount of implicit interest paid by banks in fact depends crucially upon the amount of monopoly power available to banks as a result of entry restrictions. Competition in deposit markets drives the implicit interest rate to 0 even if the explicit deposit rate is regulated, and the existence of imperfect competition in deposit markets makes the payment of positive implicit deposit interest a theoretical possibility even if the explicit deposit rate ceiling is removed.