Modelling Mortgage Terminations in Turbulent Times

Techniques used to predict mortgage defaults during a relatively stable period proved less successful during the turbulent financial cycle of the early 1980s. An alternative specification of the relationship between defaults, homeowner equity, and interest-rate movements better captures the effect of interest rates on default probability. Results confirm the powerful effect of equity on mortgage defaults and the strong, but asymmetric, influence of interest rates on both defaults and prepayments. The new specification allows direct measurement of the interest-rate effect on defaults, distinguishing the effect when rates rise or fall.     

Mortgage Pricing: Some Provisional Empirical Results

We test some of the qualitative properties of mortgage pricing models. The models use option pricing techniques, focusing on prepayment as a call option. They imply a quite nonlinear relationship between mortgage price and coupon, interest rates and volatility. We test for both the first and second derivatives of the effects of these variables using data on Ginnie Mae mortgage backed securities. We find that the model is largely supported by the data.     

Pricing Efficiency in the Mortgage Market

Traditionally, the presence of serial correlation has been presumed to indicate an inefficient market for financial assets. As Latham [15] discusses, while the absence of serial correlation implies market efficiency, its mere presence does not imply inefficiency. Rather, market efficiency is a characteristic of security pricing. This study investigates pricing efficiency in the mortgage market. Using mortgage loan quotations for 343 institutions over a 71-week period, the empirical findings show that a wide variety of mortgage contracts are efficiently priced.     

Equity and Nonequity Determinants of FHA Single-Family Mortgage Foreclosures in the 1980s

We examine foreclosures on FHA single-family mortgages insured during the 1975–87 period. The importance of the market value of borrower equity and national house price dispersion support much earlier work emphasizing the key role of negative equity in triggering default. The lower is "mean" market-value equity, and the greater is dispersion, the greater is the fraction of borrowers likely to have negative equity. The unemployment rate and the book value of borrower equity are also shown to be significant determinants of default. Unemployment is one of those events that can force borrowers to move. The moving decision increases the likelihood of default because moving costs no longer deter default, and the costs of selling the house reduce the effective equity in the house. The book value of equity is relevant to this decision because it is what the sellers receive if they move without defaulting. Not only are both of these variables significant determinants of default, but the smaller is book equity, the greater is employment impact (with large book equity, unemployment should not matter because selling the house is preferred to default).     

Commercial Mortgage Pricing with Unobservable Borrower Default Costs

This paper develops a pricing model for commercial real estate mortgage debt that recognizes the influence of default transaction costs on the borrower's default decision. These costs are heterogeneous across borrowers and largely un-observable to the lender/investor at the time of origination or loan purchase. A recognition of these unobservable costs can explain why borrower default decisions may differ from those predicted by "ruthless" mortgage-default pricing models. We address the determinants of default choice and timing by replacing sharp default boundaries found in the ruthless models with "fuzzy" boundaries that account for investor uncertainty with respect to evaluating borrower default decisions. To implement our model, we estimate probabilities of default as a junction of time and net equity in the property. Then, given that default occurs, loss severities are modeled based on expected property value recovery net of foreclosure costs and time until the asset is actually sold. Under reasonable parameter value choices, resulting Monte Carlo simulations produce numerical mortgage price estimates as well as component default frequency and severity levels that realistically reflect default premiums and loss levels observed in the marketplace.     

An Empirical Investigation of the Contingent-Claims Approach to Pricing Residential Mortgage Debt

Despite the growth of theoretical mortgage-pricing research, few empirical tests have been published. The primary objective of this paper is to provide an empirical test of the contingent-claims approach to pricing residential mortgages. This is accomplished by examining the differences between contract mortgage rates generated by the theoretical contingent-claims model and corresponding actual rates observed for 121 consecutive months from January 1981 through January 1991. We find that the contingent-claims model produces an unbiased prediction of changes in actual rates.     

Mortgage Pricing: What Have We Learned So Far?†

Much progress has been achieved in the valuation of call options and mortgages. Preliminary evidence suggests that the observed term structure of interest rates (the full structure, not just the end-points) and a reasonable estimate of the volatility of spot rates is sufficient for pricing purposes. Knowledge of the precise nature of the interest-rate process and the exact market price of interest-rate risk, the not-well-identified determinants of the term structure, are not necessary for pricing. Moreover, the number of interest-rate state variables is also of little import, again holding the term structure and rate volatility constant.     

Mortgage Borrower Repayment Behavior: A Microeconomic Analysis with Canadian Adjustable Rate Mortgage Data

In this paper we estimate a model of mortgage borrower behavior using micro-level data on Canadian borrowers with rollover mortgages—a form of adjustable-rate mortgage. Our results suggest that the probability of default rises with a decrease in housing equity and an increase in the mortgage contract rate; however the size of these changes is relatively small. They also show that partial prepayment is sensitive to fluctuations in the rates of return from investing in housing versus other assets. For the United States experience, our results suggest that, relative to fixed-rate mortgage borrowers, adjustable-rate mortgage borrowers are more likely to default and less likely to prepay.     

Mortgage Lending Discrimination and the Decision to Apply: A Methodological Note

Previous studies of lenders' decisions to accept or reject loan applications have not accounted for the possibility that lenders discourage written applications from members of protected classes, i.e., prescreening. This paper discusses how prescreening and self-selection may bias the measurement of discrimination. Estimation techniques are developed that test and correct for such bias whether or not information is available on non-applicants.     

A Simple Model of Mortgage Insurance

This paper uses a two-period model to analyze the borrower's choice of an optimal time pattern of mortgage payments in a world where future house values are uncertain. Since a decline in values can make the borrower's equity negative, leading to default on the mortgage, lenders in the model will require the purchase of mortgage insurance. The premium on the insurance policy will depend on the riskiness of the mortgage, which in turn depends on the magnitude of the initial mortgage payment. Mortgages with large (small) first payments will carry low (high) insurance premiums. Taking this fact into account, the borrower decides on the optimal riskiness of his mortgage. Borrowers who discount the future heavily choose risky mortgages carrying high insurance premiums, while those who place a higher value on future consumption opt for less risky contracts carrying low (or zero) premiums.     

Mortgage Prepayment and Default Decisions: A Poisson Regression Approach

This paper uses an extensive and geographically dispersed sample of single-family fixed rate mortgages to assess the prepayment and default behavior of individual homeowners. We make use of Poisson regression to efficiently estimate the parameters of a proportional hazards model for prepayment and default decisions. Poisson regression for grouped survival data has several advantages over partial likelihood methods. First, when dealing with time-dependent covar-iates, it is considerably more efficient in terms of computations. Second, it is possible to estimate full-hazard models which include, for example, functions of time as well as multiple time scales (i.e., age of the loan and calendar time), in a much more straightforward manner than partial likelihood methods for un-grouped data. Third, Poisson regression can be used to estimate non-proportional hazards models such as additive excess risk specifications. Taken together, our data and estimation methodology allow us to obtain a better understanding of the economic factors underlying prepayment and default decisions.     

A Note on Mortgage Risk: Default vs. Loss Rates

This note reexamines the role of the loan-to-value ratio on mortgage risk. Whereas previous studies have focused on the default rate as a function of this term, this study considers the additional effect on the loss rate of defaulted loans. Because the dollar loss per amount originated is the product of the default rate and the loss rate on defaulted loans, the impact of the loan-to-value ratio on both the default and loss rates is crucial to explaining the impact of the loan-to-value ratio on mortgage risk. I find that both rates are significantly positively related to loan-to-value ratio and that the loss rate accounts for between 13% and 20% of total loan-to-value impact.     

Handing Over the Keys: A Perspective on Mortgage Default Research

This paper is the text of the 1992 Presidential Address for the American Real Estate and Urban Economics Association. A comparative evaluation of mortgage default research finds that both the residential and commercial markets evolved from informal underwriting rules, to formalized (though unvalidated) ratios and rules of thumb, to early risk ratings based upon empirical evidence, to gener-alizable econometric models of default, to option-based pricing models. The commercial market lagged the residential market by about 10 to 20 years at first but is now only about five years behind. The survey finds that research and progress in understanding mortgage credit risk has been precipitated by a public policy need or mandate, data availability, and adequate technology. The absence of any one of these factors has hindered progress in the past. Finally, six emerging issues in default research are identified and discussed: (1) the degree of "ruth-lessness" with which default is exercised, (2) loan recourse, (3) the magnitude and timing of revenues and losses associated with default, (4) loan modification, (5) default in a portfolio context, and (6) leasehold default. Progress in these areas will enhance the efficiency of both the residential and commercial markets.     

A Research Note on Discrimination in Mortgage Lending

This paper examines the hypothesis that mortgage lenders rank applications from better to worst and encourage the better ones to apply. A second ranking occurs when the application is ranked by the loan committee and funds are approved from the top of the list until exhausted. A theoretically correct procedure for analyzing the resulting multivariate ordinal data is the little known rank multiple discriminant analysis. Preliminary results have revealed that this technique produces a "best" model with fewer variables and a higher classification rate than the commonly known multiple discriminant analysis, logit, or probit.     

Elective Mortgage Prepayment: Termination and Curtailment

Mortgage-prepayment risk underlies the structuring of mortgage-backed derivative securities, such as tranched real estate mortgage investment conduits. This prepayment comes either from mortgage termination or from curtailment, where the borrower retains the existing mortgage and prepays a portion. There are differences in cash flows from the two types of prepayment. In termination, the loan disappears from a pool, and the scheduled payment to investors in the pool is reduced. In curtailment, the loan survives, and the scheduled payment is unchanged but the term is reduced. There are implications for structuring mortgages and derivative securities. The prepayment decision is embedded in an in-tertemporal household utility maximization framework where choices are made between refinancing, making the regular payment, default or curtailment. Empirical results are presented for Government National Mortgage Association (GNMA) pools, and an algorithm is presented that separates the termination and curtailment components, facilitating the development of derivative securities.     

A Model of Localized Mortgage Lending Behavior*

Loan administration costs and the costs of search for information about risk are found to be determinants of spatial interest rate differentials. These costs are independent of dollar loan size; therefore, rational lending policies can produce higher interest rates (or lower term to maturity) in low-income communities. But the premium (lower maturity) should be related to lower loan size and risk differentials. Public policy should be directed toward compiling and verifying an information bank which would allow lenders to search efficiently for information about risk. An empirical methodology designed to test for mortgage deficiency in minority areas was developed through case studies. This indicated the utility of specifying the supply and demand for mortgages at the neighborhood level of aggregation. Trends in neighborhood property values were identified as important and overlooked measures of lending risk. Further exploration of the hypothesis that Spanish-speaking areas are mortgage deficient is suggested by the cases.     

The Mortgage Acquisition Process: A Comparison of VRM and FRM Borrowers*

In recent years a number of alternative types of residential mortgage plans (i.e., alternative to the fixed-rate level-payment mortgage) have been proposed, and some of these have been available in various parts of the country. The most often proposed innovation has been the variable rate mortgage (VRM). The most widespread use of the VRM has been in the State of California, starting in early 1975. This paper discusses some of the results of a survey of over 1,700 homeowners in California that examined consumer reaction to the VRM. Specifically, this paper looks at the impact of the VRM on the mortgage acquisition process and the features of mortgages demanded by consumers. The data seem to indicate that the process of acquiring a mortgage has not been affected significantly by the availability of the VRM. However, the existence of alternative mortgage plans means that consumer choice can be broadened to include type of mortgage as well as lending institution.     

The Asset Approach to Pricing Urban Land: Empirical Evidence

Many papers have attempted to explain Intelmetropolitan variations in the price of housing using multi-equation models of the metropolitan housing market. This paper uses a long-run equilibrium urban asset model to explain such variations. The model builds upon previous models that introduce uncertainty into the dynamic urban model of land conversion. The empirical results strongly support the asset approach to valuing land in urban areas.