This paper empirically investigates the issues of depositor discipline by examining deposit shifts among Japan's small banking institutions in the 1990s. We are concerned with two questions: (i) whether depositor discipline has effectively worked since the early 1990s, and (ii) whether changes in the regulatory frameworks, including the deposit insurance scheme, affect depositor discipline. Our findings support the effective role of market discipline by depositors. Riskier institutions attract smaller amounts of deposits and are required to pay higher interest rates. Depositor sensitivity to bank risks has changed over time, in compliance with the historical developments of the deposit insurance system.JEL Classification Numbers: G21, G32.