The purpose of this paper is to analyse the viewpoints and judicial practice of setting off debts by a bank against the claims of a debtor. The banks benefit from a privilege that allows them to deduct from their claims a claim that has not yet matured in cases specified in Article 93(2) of the Banking Act. The paper also presents the sources of controversies over the privileges of banks in contemporary market economy, and the relationships between the provisions governing statutory set-offs in the Banking Act and the Civil Code, as applicable to banking practice. Bank set-offs constitute an exception from the rule that only matured claims may be offset, and thus a strict interpretation of the provisions governing them is necessary. The issue of the extent to which bank set-offs is exempted from the claim maturity rule raises fundamental controversies.