A Bank of Korea analysis found that a 1 percentage point increase in interest rates would raise the delinquency rate among highly leveraged home-buying households by 0.81 percentage points after one year. The increase exceeds the estimated rises for existing homeowners, at 0.52 percentage points, and ordinary home-buying households, at 0.64 percentage points. The report, titled "Assessment of Household Debt Risk Using a Household Database," defines highly leveraged home buyers as households that took out a new mortgage between 2023 and 2025 and ranked in the top 10% for the increase in debt-service payments relative to income. A separate stress test found that a 0.25 percentage point rate increase would lift the overall delinquency rate by 0.27 percentage points after 12 months, with larger increases among the lowest-income households and self-employed business owners. Although average household debt indicators have improved, the share of borrowing households with at least one delinquent member rose to 3.35% at the end of last year, while the rate was 5.45% for the bottom income quintile and 4.47% for self-employed business owners and corporate representatives. The study also found that delinquency spread to another member within 12 months in 8.8% of highly leveraged households, compared with 4.6% of existing homeowner households. Consumption weakened when the debt-service ratio exceeded 46%, a threshold surpassed by 11.1% of debt-holding households and 14.5% of those in the bottom income quintile. The findings support assessing where debt risk is concentrated, rather than relying only on average indicators, while Yonsei University professor emeritus Kim Jung-sik warned that lending-volume restrictions alone would not resolve the drivers of high home prices or household debt risk.