A. The Defendant is a corporation that runs the business of issuing, selling, and managing credit cards or pre-paid cards. The Plaintiffs are those who used or used credit cards, etc. upon entering into a contract for the use and financial transaction with the Defendant.

B. The concept of the card accident analysis system and the introduction card accident analysis system (hereinafter “FDS”) are introduced by all domestic credit card companies as a system to detect abnormal or fraudulent use due to theft, loss, forgery, etc. of credit cards. According to FDS, an analysis model is made based on statistical methods using large-scale card use information and pertinent customer information based on past accident transactions and based on this, if it is discovered that abnormal types of transactions have occurred according to the statistical analysis pattern of the credit card when using the credit card.

C. Defendant’s disclosure of customer information 1) Conclusion of FDS development services contracts and Defendant to provide card customer information is a stock company B around 2009 (hereinafter “B”).

(2) After the introduction of FDS through B, the need for the FDS was raised, and around May 2012, the development service contract was concluded to trade the FDS, which was newly constructed with B. During the FDS development project period, the credit card customer information not converted to B was provided for the necessity of the development project, and the project general manager C, etc. used the FDS development from May 2012 to December 2012. (2) On June 2012, 2012, the credit card customer information leakage was done by the Defendant bank’s office on the 10th floor of the Seodaemun-gu Seoul Western Building, Seodaemun-gu, Seoul, for business convenience, at the Defendant bank’s office, one of the team members of B’s computer operating systems, instead of the Defendant’s Internet server operating system.