Commercial banks saw the delinquency rate on loans collateralized by apartments climb to the highest level in more than six years, regulatory data showed Thursday.

According to the Financial Supervisory Service, the delinquent mortgage loan ratio was 0.94 percent in January, compared with 0.74 percent a month earlier and 0.69 percent a year earlier.

Rising sharply to 0.94 percent, last recorded in October 2012, it marked the highest rate in 76 months since the sourced loan ratio reached 1.03 percent in August 2006.

An FSS official said the “sluggish property market” has led to several insolvent loans collateralized by housing.

Including mortgage loans and credit-based loans, the banking industry posted a seriously high delinquency rate on household loans.

The ratio of delinquent household lending ― mortgage loans plus credit-based loans ― posted 0.99 percent in January, compared with 0.81 percent on-month and 0.78 percent on-year.

After the 1.01 percent figure from August 2012 and October 2012, January’s ratio marked the next highest in about six years since the sourced loan ratio reached 1.07 percent in October 2006.

Korea saw household debt ― from commercial banks and other lenders ― reach an all-time high of about 960 trillion won ($885 billion), which could possibly be linked to a massive increase of credit delinquents.

By Kim Yon-se (kys@heraldcorp.com)