Pedestrians pass Citibank Korea’s headquarters in central Seoul yesterday. Prosecutors announced yesterday that personal information of 130,000 customers of Citibank and Standard Chartered Korea was found to have been leaked. [NEWS1]

Personal information of about 130,000 customers of Citibank and Standard Chartered was recently discovered to have been leaked by insiders, triggering alarm over inadequate security systems at financial institutions.

The leaked information included names, addresses, phone numbers, account numbers and loan interest rates.

The Changwon District Prosecutors’ Office yesterday said it arrested a 37-year-old employee surnamed Park from Citibank, who worked in management, and a 40-year-old employee surnamed Lee, who worked for Standard Chartered’s IT outsourcing company. They are charged with violating the country’s real-name financial transaction law and information communications network law.

Among the cases of leaked personal information, 100,000 are from Standard Chartered and 30,000 are from Citibank.

Prosecution sources said Park from Citibank allegedly printed out information about people who had received loans in April. Park then allegedly delivered the printed copies to an outsider. Lee is suspected of copying a file with information about more than 100,000 Standard Chartered customers from an internal network onto a USB on multiple occasions from November 2011 to February 2012.

The two incidents under investigation come at a time of concerns over security systems at local financial institutions. In recent years, there have been a number of incidents where information of financial consumers has been hacked or compromised by an insider.

In 2011, Hyundai Capital, the financial arm of Hyundai Motor Group, said private data and financial records of about 1.75 million members were stolen by hackers. Recently, information of more than 160,000 customers at Meritz Fire and Marine Insurance was sold by one of its employees for more than 10 million won ($9,500).

The country’s financial regulator has been working to tighten security at financial institutions by advising them to implement more encoded programs and imposing tougher penalties for information leaks.

Meanwhile, both Citibank and Standard Chartered said yesterday that they will come up with internal measures to prevent further leaks. An official from Standard Chartered also said it has launched its own internal investigation.

“We fired the employee today,” said an official from Citibank. “We will actively cooperate fully with the investigation and come up with measures to prevent incidents like this from recurring.”

BY LEE EUN-JOO [angie@joongang.co.kr]