Buying RTG will increase Labat's revenue.

Seoul - A massive theft of customer data from three major credit card firms in South Korea has shown security lapses in the financial industry.

Financial Services Commission Chairman Shin Je-yoon said Monday the credit card companies had failed to ensure adequate security.

The chief financial regulator urged credit companies to be vigilant about data theft not only by hackers but also by employees and contractors.

Prosecutors said last week an employee of a contractor stole the data of 80 million credit card customers beginning in 2012 by copying data to a USB device.

Another official said the stolen data from Lotte Card Co. and the credit card units of KB Financial Group and NongHyup Bank was unencrypted.

He said the companies were unaware of the theft until prosecutors began an investigation. - Sapa-AP