A. 1) The Defendant is a company engaged in the business of issuing, selling, and managing credit cards, pre-paid cards, debit cards, and debit cards. 2) The Plaintiffs are those who used or used credit cards, etc. after concluding a contract with the Defendant 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 transactions or fraudulent use due to the theft, loss, forgery, etc. of credit cards.

According to the above FDS, when it is discovered that a large amount of card use information and customer information were used based on the past accident transaction and that there were abnormal types of transaction according to statistical techniques based on the results, it is possible to take measures such as refusing to grant credit card approval if it is discovered that there was abnormal type of transaction according to an accident pattern analyzed in the course of using credit cards.

C. The Defendant’s disclosure of customer information (1) concluded the FDS development service contract and (1) provided customer information for the first time in 2008, and the need of the FDS was raised, and the Defendant entered into a contract with M Co., Ltd. (hereinafter “M”) on January 30, 2013 for purchase related to the FDS business within seven months from the date of concluding the contract.

B) The development personnel, including N, of the project as above, input into the Defendant from February 2013 to August 2013, 2013, and started the FDS development work. ① From February 2013 to March 2013, it is necessary to consult with the Defendant’s claims management and business requirements, and, thus, work at the Defendant’s headquarters located in the Seoul Jongno-gu Seoul Metropolitan Government inland Dong; ② from March 2013 to August 2013, 2013, the Defendant worked at the Defendant’s Scdong Computer Center located in the Gangseo-gu Seoul Metropolitan Government Seodong-dong. (C)