The rise of risk-based pricing of mortgage interest rates in Italy

This paper assesses how much mortgage interest rates in Italy are priced on credit risk as proxied by the probability of household mortgage delinquency estimated using the EU-Silc database. Owing to data availability, we restrict the analysis of mortgage pricing to Italian households. Consistent with the more widespread use of credit scoring, estimates indicate that Italian lenders have increasingly priced mortgage interest rates on household credit risk. For mortgages granted between 2000 and 2007, we find that a 1% point increase in the probability of default is associated with a 21 basis point rise in mortgage interest rates, lower than the 38 basis point premium Edelberg (2006) estimated for the US at the end of the 1990s.     

Credit History and the Performance of Prime and Nonprime Mortgages

Although nonprime lending has experienced steady or even explosive growth over the last decade very little is known about the performance characteristics of these mortgages. Using data from national secondary market institutions, this paper estimates a competing risks proportional hazard model, which includes unobserved heterogeneity. The analysis examines the performance of 30-year fixed rate owner occupied home purchase mortgages from February 1995 to the end of 1999 and compares nonprime and prime loan default and prepayment behavior. Nonprime loans are identified by mortgage interest rates that are substantially higher than the prevailing prime rate. Results indicate that nonprime mortgages differ significantly from prime mortgages: they have different risk characteristics at origination; they default at elevated levels; and they respond differently to the incentives to prepay and default. For instance, nonprime mortgages are less responsive to how much the option to call the mortgage or refinance is in the money and this effect is magnified for mortgages with low credit scores. Tests also reveal that default rates are less responsive to homeowner equity when credit scores are included in the specification.     

Credit derivatives with multiple debt issues

We evaluate the most actively traded types of credit derivatives within a unified pricing framework that allows for multiple debt issues. Since firms default on all of their obligations, total debt is instrumental in the likelihood of default and therefore in credit derivatives valuation. We use a single factor interest rate model where the exponential default frontier is based on total debt and is made coherent with observed bond prices. Analytical formulae are derived for credit default swaps, total return swaps (both fixed-for-fixed and fixed-for-floating), and credit risk options (CROs). Price behaviors and hedging properties of all these credit derivatives are investigated. Simulations document that credit derivatives prices may be significantly affected by terms of debt other than those of the reference obligation. The analysis of CROs indicates their superior ability to fine-tune the hedging of magnitude and arrival risks of default.     

A practical approach to validating a PD model

The capital adequacy framework Basel II aims to promote the adoption of stronger risk management practices by the banking industry. The implementation makes validation of credit risk models more important. Lenders therefore need a validation methodology to convince their supervisors that their credit scoring models are performing well. In this paper we take up the challenge to propose and implement a simple validation methodology that can be used by banks to validate their credit risk modelling exercise. We will contextualise the proposed methodology by applying it to a default model of mortgage loans of a commercial bank in the Netherlands.     

Mortgage Termination: An Empirical Hazard Model with a Stochastic Term Structure

Pricing for mortgage and mortgage-backed securities is complicated due to the stochastic and interdependent nature of prepayment and default risks. This paper presents a unified economic model of the contingent claims and competing risks of mortgage termination by prepayment and default. I adopt a proportional hazard framework to analyze these competing and interdependent risks in a model with time-varying covariates. The paper incorporates a stochastic interest rate model into the hazard function for prepayment. The empirical results reported in the paper provide new evidence about the ruthlessness of default and prepayment behavior and the sensitivity of these decisions to demographic as well as financial phenomena. The results also illustrate that evaluating the interest rate contingent claims with a stochastic term structure has effects on predicting not only the mortgage prepayment behavior but also the mortgage default behavior.     

When it comes to the crunch: What are the drivers of the US banking crisis?

This article considers how permissive regulatory conditions helped change the size and scope of the US mortgage market. Asset backed securitization facilitated an expansion of the US mortgage market and modified the structure of the value chain within which financial assets, risk and liquidity were managed. New sophisticated mortgage products, indulgent lending practices, loose credit assessment and flimsy documentation increased the probability of mortgage default in an economic downturn. US banks were not in a position to absorb mark-to-market losses on mortgage assets and goodwill impairment resulting from a credit crunch because they operate with narrow profit margins and a limited equity cushion in the balance sheet. This article questions the viability and sustainability of this banking business model.     

Determinants of Mortgage Default and Consumer Credit Use: The Effects of Foreclosure Laws and Foreclosure Delays

The mortgage default decision is part of a complex household credit management problem. We examine how factors affecting mortgage default spill over to other credit markets. As home equity turns negative, homeowners default on mortgages and home equity lines of credit at higher rates, whereas they prioritize repaying credit cards and auto loans. Larger unused credit card limits intensify the preservation of credit cards over housing debt. Although mortgage nonrecourse statutes increase default on all types of housing debt, they reduce credit card defaults. Foreclosure delays increase default rates for housing and nonhousing debts. Our analysis highlights the interconnectedness of debt repayment decisions.     

Book review of Fault Lines by Raghuram G. Rajan

Most people believe that the recent financial crisis had its roots in a boom in housing lending in the United States. After the dot-com bubble, the argument goes, the Federal Reserve Bank lowered the interest rates to stimulate corporate investment and recover from the downturn. As a side effect of low interest rates, mortgages became cheaper and Americans became attracted to the housing market. Credit for housing was provided by the sophisticated financial system of the United States, which allowed investors to purchase packages of mortgages from diversified geographical locations, and from individuals with different probabilities of default, according to their desired level of risk. As it turned out, these products caught the attention of investors from all over the world, who were attracted by their profitable returns and the implicit guarantees provided by the U.S. government to the issuing agencies and financial intermediaries. Therefore, housing credit was plentiful and, as a consequence, house prices in the United States rose. This in turn allowed mortgage borrowers to refinance their debts and avoid default. The party came to an end when interest rates increased and house prices fell, triggering a series of defaults in mortgages and driving values of the financial products near to zero, resulting in consequences with which we all are too familiar.     

An Analysis of Mortgage Termination Risks: A Shared Frailty Approach with MSA-Level Random Effects

Investigating the residential mortgage defaults and prepayments has been the subject of research for the past three decades. The literature on mortgage default and prepayment is often used to inform credit risk policies and asset pricing strategies. This literature has evolved from the use of logistic regressions to the use of survival and frailty models that control for unobserved heterogeneity. In this paper, we apply a shared-frailty survival model to analyze the mortgage termination risks. In particular, we investigate whether mortgages originated in the same Metropolitan Statistical Area (MSA) share common unobserved factors and how these factors affect the mortgage termination risks. The paper demonstrates that MSA-level frailty, together with other risk factors, has significant effects on the probability of mortgage terminations risks.     

Identifying the determinants of mortgage default in Colombia between 1997 and 2004

This paper examines the relationship between mortgage default decisions and relevant observable variables in Colombia between 1997 and 2004. We estimate a discrete choice model of default using a panel of individual mortgage characteristics and payment information. We show that home prices and debt balances are the main determinants of mortgage default. We account for the presence of unobserved heterogeneity using Survey data and simulation techniques. Including controls for the distribution of income shows that income was not important but helps clarifying the relevance of mortgage leverage in the determination of the observed default rates.     

Legal Restrictions in Personal Loan Markets

This study examines the pricing of personal loans in the form of second mortgages to determine whether state-specific default laws have an effect on the availability and cost of that debt. We examine the pricing of loans to higher risk borrowers and whether borrowers in states that limit lender ability to seek default remedies pay higher credit costs. Our results indicate that, for the most part, lenders rationally price loans to higher risk borrowers. However, when we focus on borrowers with low credit scores, the results indicate that mean actual loan rates are higher than those predicted by our model. The results also indicate that state-specific default laws have an effect on the price of credit. Finally, the results show that there is a greater degree of error in the pricing of second mortgage loans to borrowers with low credit scores than to borrowers with high credit scores.     

Mortgage timing

We study how the term structure of interest rates relates to mortgage choice at both household and aggregate levels. A simple utility framework of mortgage choice points to the long-term bond risk premium as distinct from the yield spread and the long yield as a theoretical determinant of mortgage choice: when the bond risk premium is high, fixed-rate mortgage payments are high, making adjustable-rate mortgages more attractive. We confirm empirically that the bulk of the time variation in both aggregate and loan-level mortgage choice can be explained by time variation in the bond risk premium, whether bond risk premia are measured using forecasters’ data, a vector autoregressive (VAR) term structure model, or a simple household decision rule based on adaptive expectations. The household decision rule moves in lock-step with mortgage choice, lending credibility to a theory of strategic mortgage timing by households.     

Collateral Risk in Residential Mortgage Defaults

This paper presents a systematic framework for capturing the collateral-driven mortgage default risk. A forward-looking home price distribution model is developed that explicitly incorporates different sources of volatility in the market value of collateral houses. A consistent and computationally-efficient top-down approach of home price simulation is also introduced. We show that with the proper inclusion of all relevant sources of volatilities, the top-down approach provides close approximation to the results generated by a theoretically sound but computationally demanding bottom-up simulation approach. Using a numerical simulation, we demonstrate that a geographically-diversified mortgage pool entails a substantially lower level of systematic collateral driven mortgage default risk compared to a spatially-concentrated pool. However, the expected default risk is shown to remain unaffected, indicating that the benefit from geographic diversification is only realized through lower risk-based capital requirements, not in lower mortgage insurance premiums. Based on the US state level house price indices, the systematic risk of a state-concentrated mortgage pool is estimated to be about four times higher than that of a nationally-diversified mortgage pool. Our results also show that, among the different volatility components, omitting the cross-sectional dispersion of individual home prices would produce the largest bias in assessing home-price-based mortgage default risk.     

个人住房抵押贷款违约风险跃迁概率研究

巴塞尔新资本协议提出针对个人住房抵押贷款可采用内部评级高级法评估其风险,在满足某些最低条件和披露要求的前提下,商业银行可根据自己对个人住房抵押贷款违约概率、违约损失率、违约风险暴露和期限等要素的估计值确定相应的资本要求。本文提出将风险跃迁概率引入到对个人住房抵押贷款提前还款-违约概率的定量估计中。借助逻辑斯特模型,本文将这一概念实际运用到对个人住房抵押贷款微观数据的分析当中,得到的实证研究结论包括借款人历史还款状态可以作为表征其未来还款状态的重要指标,贷龄与借款人还款状态的跃迁概率显著相关等。     

A framework to measure integrated risk

A framework underlying various models that measure the credit risk of a portfolio is extended in this paper to allow the integration of credit risk with a range of market risks using Monte Carlo simulation. A structural model is proposed that allows interest rates to be stochastic and provides closed-form expressions for the market value of a firm's equity and its probability of default. This model is embedded within the integrated framework and the general approach illustrated by measuring the risk of a foreign exchange forward when there is a significant probability of default by the counterparty. For this example moving from a market risk calculation to an integrated risk calculation reduces the expected future value of the instrument by an amount that could not be calculated using the common pre-settlement exposure technique for estimating the credit risk of a derivative.     

Pathways After Default: What Happens to Distressed Mortgage Borrowers and Their Homes?

We use a detailed dataset of seriously delinquent mortgages to examine the dynamic process of mortgage default—from initial delinquency and default to final resolution of the loan and disposition of the property. We estimate a two-stage competing risk hazard model to assess the factors associated with post-default outcomes, including whether a borrower receives a legal notice of foreclosure. In particular, we focus on a borrower’s ability to avoid a foreclosure auction by getting a modification, by refinancing the loan, or by selling the property. We find that the outcomes of the foreclosure process are significantly related to: loan characteristics including the borrower’s credit history, current loan-to-value and the presence of a junior lien; the borrower’s post-default payment behavior, including the borrower’s participation in foreclosure counseling; neighborhood characteristics such as foreclosure rates, recent house price depreciation and median income; and the borrower’s race and ethnicity.     

Unintended Consequences of Risk Based Pricing: Racial Differences in Mortgage Costs

The following analysis focuses on the role that risk pricing has had in the allocation and access to mortgage funds, specifically how it results in cost differences by race. Using a sample of fixed-rate first lien mortgages, we control for the risk characteristics of borrowers and assets. We find that borrowers with comparable credit quality experience significantly higher costs for mortgages in neighborhoods with a high density of minority households. Further, when the pricing differential is controlled for in a model of mortgage default, there is no support for neighborhood price differences. This finding illustrates a potential inequity that results from efficient/risk pricing in mortgage underwriting.     

On cox processes and credit risky securities

A framework is presented for modeling defaultable securities and credit derivatives which allows for dependence between market risk factors and credit risk. The framework reduces the technical issues of modeling credit risk to the same issues faced when modeling the ordinary term structure of interest rates. It is shown how to generalize a model of Jarrow, Lando and Turnbull (1997) to allow for stochastic transition intensities between rating categories and into default. This generalization can handle contracts with payments explicitly linked to ratings. It is also shown how to obtain a term structure model for all different rating categories simultaneously and how to obtain an affine-like structure. An implementation is given in a simple one factor model in which the affine structure gives closed form solutions.     

Catastrophic Default and Credit Risk for Lending Institutions

Mortgage insurance does insure lenders against most ordinary default: that default induced by price movements in the overall housing market. However, private mortgage insurance typically excludes coverage of the truly catastrophic default resulting from such acts of God as fire, floods, earthquakes, and hurricanes, increasingly familiar in the United States in recent years. Often, these events affect a substantial portion of the houses within a particular neighborhood or region; and if disaster insurance or government aid is inadequate or nonexistent, the default is likely to occur, putting the credit institution at risk. This paper uses a two-state option model with an added jump process that accounts for the possibility and severity of a catastrophe. The paper then uses that information to determine the credit risk to a lender. In addition, this article goes beyond the standard market valuations typical of an option model in reporting the distribution of events that average up to the market cost of the lenders liability. This involves doing probability calculations not present in the usual valuation determinations of option pricing. The point of this article is that the option-pricing methodology provides the means for calculating such probability distributions, thus improving credit risk evaluations for the lender.     

Residential Mortgage Default: The Roles of House Price Volatility, Euphoria and the Borrower’s Put Option

House price volatility; lender and borrower perception of price trends, loan and property features; and the borrower’s put option are integrated in a model of residential mortgage default. These dimensions of the default problem have, to our knowledge, not previously been considered altogether within the same investigation framework. We rely on a sample of individual mortgage loans for 20 counties in Florida, over the period 2001 through 2008, third quarter, with housing price performance obtained from repeat sales analysis of individual transactions. The results from the analysis strongly confirm the significance of the borrower’s put as an operative factor in default. At the same time, the results provide convincing evidence that the experience in Florida is in part driven by lenders and purchasers exhibiting euphoric behavior such that in markets with higher price appreciation there is a willingness to accept recent prior performance as an indicator of future risk. This connection illustrates a familiar moral hazard in the housing market due to the limited information about future prices.