한국 모기지시장의 채무불이행 및 조기상환 분석

prepayment behaviors in the Korean mortgage markets. In particular, we examine the factors that play major roles in determining default and prepayment,investigate the seasoning effect in the default and the prepayment, and explore whether there is any difference between Seoul (hot housing market)and Pusan (cold housing market). We use 145,782 mortgage loans, which KHFC (Korea Housing Finance Corporation) securitized from January 2004 to December 2007. Of these there are 21,069 mortgage loans originated in Seoul and 12,503 mortgage loans in Pusan. The KHFC mortgages in the sample have the maximum maturity of 20 years and the maximum LTV of 70%. The average LTV of the overall sample is 60.3%; the average LTV is 57.8% in Seoul while the average LTV is 60.9% in Pusan. The initial loan amount is KRW 74 million in the overall sample, KRW 111 million in Seoul and KRW 66 million in Pusan. The prepayment penalties of KHFC mortgages are 2% if prepayment occurs within 1 year, 1.5% within 3 years and 1% within 5 years. We use 90 days arrears as the proxy for loan default consistent with the Basel II. Contrary to our expectation that the default rate in the regional market as such Pusan would be higher than that in Seoul, which experienced a sharp price run-up during the study period, we find that the default rate in Seoul is higher and the difference is statistically significant. During the study period of 2004~2007 the cumulative default rate is 0.78%in the overall markets, 1.40% Seoul and 1,10% in Pusan. We find that the default is higher, lower the credit rating, lower the past house price increase, higher the mark-to-market loan-to-value ratio (MLTV), and higher the DTI. The self-employed borrowers show a lower default rate. These findings are consistent with economic theories and findings reported in other markets. We find little difference in the factors that influence the mortgage default between Seoul and Pusan. The prepayment rate rises as the mortgage rate drops below the contract mortgage rate. It rises right after the 12 months and 36 months of loan age to coincide with the reduction in the prepayment penalty. The prepayment rate is higher, higher the MLTV and higher the mortgage balance. We find little difference in the factors that influence the mortgage prepayment between Seoul and Pusan. During the study period, the prepayment rate is 20.06% in the overall markets, 20.55% in Seoul and 17.73%in Pusan. From the CDR(conditional default rate) and the CPR(conditional prepayment rate) we estimate using the Kaplan-Meier product limit method,we find that the seasoning effect exists in the Korean mortgage markets as in the US mortgage markets. Therefore, using the US benchmark default model (SDA) and the US benchmark prepayment model (PSA) the estimated CDR is approximately 50~100% SDA in the overall markets and in Seoul and 50~150% SDA in Pusan while the estimated CPR is approximately 150~250% PSA in the overall markets and Seoul and 100~200% PSA. The estimated CDR and CPR statistical models, which express the CDR and CPR as a function of the age of the mortgage loan respectively,provide a valuable benchmark for practitioners. Financial institutions carrying a significant amount of mortgage loan assets would find the estimated default model useful for the credit risk management while the estimated prepayment model provides useful information for the duration management of the mortgage loan assets and the MBS that are based on these assets.