Citibank Taiwan Ltd offered customers credit card prepayment transaction services but failed to duly conduct tests and reviews of relevant credit card information systems before and after system implementation. Citibank Taiwan also failed to properly crosscheck messages derived from different credit card information systems so that it was unable to discover false prepayment transactions, without any fund transferred, and related credit card spending activities made by customers. Citibank Taiwan did not have an effective fraud prevention control mechanism in place to detect the abnormality of customers’ credit card transactions and failed to provide information to related departments for identifying and monitoring abnormal transactions. Citibank Taiwan was thus in violation of the Article 33 of Regulations Governing Institutions Engaging In Credit Card Business authorized by Paragraph 1, Article 47-1 of the Banking Act. Citibank Taiwan was fined NT$2.5 million under Article 132 of the Banking Act.