DATA AND METHODOLOGY
Data
The current study used operating margins, non-performing loan (NPL) ratio, adjusted capital ratio, liquidity ratio, asset size, economy growth rate, market interest rate, and interest rate for extending and receiving credit as variables representing the internal and external factors impacting credit card firms. The definitions of the variables and calculating formula are presented in Table 1. The period of analysis was from the first quarter of 2000 to the fourth quarter of 2011, and the data were obtained from the financial statistics information of the Korean Financial Supervisory Service and from the financial database; FnGuide. In