Knowledge that Transforms

It is well known that long-term interest rates display a lower volatility than short-term interest rates. The imperfect correlation between changes in long-term and short-term interest rates is also well documented. Simple immunization techniques based on duration and convexity do not take such factors into account. This paper suggests an approach which considers unequal volatility and imperfect correlation when building immunizing portfolios. Our results suggest that this approach may lead to significant improvements over both duration-based and convexity-based immunization strategies. Volatility-adjusted and correlation-adjusted immunization also outperform strategies based on factor analysis of interest rates changes.

This paper estimates multi-product cost functions for nearly 900 thrifts from 1990 to 1995. The results show the thrift industry benefited in the 1990s from a combination of reduced scale diseconomies, technical progress, and industry consolidation. The 1990 sample is characterized by substantial diseconomies of scale, which increased with thrift size, while the 1995 sample shows thrifts of all sizes operating with constant returns to scale. Sample selection is an important issue since there are fundamental differences between the thrifts that exited the industry during the 1990s and those that survived through the 1990s. If one examines all operating thrifts each year, for example, estimates of technical progress are biased upward, since large, inefficient thrifts regularly exited the industry in the 1990s.

This paper attempts to estimate both the direct and indirect costs of regulation for major sectors of the UK financial services industry. We also compare UK direct costs with those for the US and France and this provides a benchmark for assessing the effect of regulation on the competitive position of the UK financial services industry. We believe that this is the first attempt to compare regulatory costs in the UK with those of its major competitors. For indirect costs, in the absence of an international benchmark we compare our results with the predictions made at the time of the introduction of the Financial Services Act, by Lomax (Lomax, D., 1987. London Markets After the Financial Services Act, Butterworths, London) and Goodhart (Goodhart, C., 1988. The costs of regulation. In: Seldon, A. (Ed.), Financial Regulation or Over-regulation. Institute of Economic Affairs, London, p. 31). They estimated that indirect costs would be £4 for every £1 of direct costs and that annual aggregate costs would be £100 million. Our results suggest that, so far as direct costs are concerned, the costs of regulation for the securities and derivatives trading and broking sector are substantially lower for the UK than for the US and France. In contrast, for the investment management and unit trust industry UK costs are significantly higher than those for the other two countries. For the life insurance industry, UK costs are similar to those in France but markedly lower than those for the US. We also find for the securities industry around £4.1 of indirect costs per £1 of direct costs. For the investment management industry the corresponding figure is £3.2. However there is substantial variation across firms and, although our sample is too small to be definitive, the ratio appears to be related to firm size. Although these results are broadly in line with the predictions of Lomax and Goodhart it should be borne in mind that both numerator and denominator are substantially higher in real terms than those used by Lomax and Goodhart.

This paper finds that the returns of the world's 14 major stock markets are not normally distributed, and that the correlation matrix of these stock markets was stable during the January 1988–December 1993 time period. Polynomial goal programming, in which investor preferences for skewness can be incorporated, is utilized to determine the optimal portfolio consisting of the choices of 14 international stock indexes. The empirical findings suggest that the incorporation of skewness into an investor's portfolio decision causes a major change in the construction of the optimal portfolio. The evidence also indicate that investors trade expected return of the portfolio for skewness.

We value American options on bonds using a generalization of the Geske–Johnson (Geske, R., Johnson, H., 1984. Journal of Finance 39, 1151–1542) (GJ) technique. The method requires the valuation of European options, and options with multiple exercise dates. It is shown that a risk-neutral valuation relationship (RNVR) along the lines of Black–Scholes (Black, F., Scholes, M., 1973. Journal of Political Economy 81, 637–659) model holds for options exercisable on multiple dates, even under stochastic interest rates, when the price of the underlying asset is lognormally distributed. The proposed computational procedure uses the maximized value of these options, where the maximization is over all possible exercise dates. The value of the American option is then computed by Richardson extrapolation. The volatility of the underlying default-free bond is modeled using a two-factor model, with a short-term and a long-term interest rate factor. We report the results of simulations of American option values using our method and show how they vary with the key parameter inputs, such as the maturity of the bond, its volatility, and the option strike price.

A model of mean reversion of exchange rates to purchasing power parity is developed and tested where exchange rates are assumed to follow a mean reverting elastic random walk toward a stochastic PPP rate. The model recognizes the possibility that mean reversion towards PPP may be nonlinear which allows greater flexibility in the adjustment process. Regression equations consistent with the theoretical model are derived. The model is tested using long- and short-term data for six countries. While the results are generally consistent with the findings of previous studies, evidence is presented which demonstrates that the mean reversion process is not linear for some countries.

This paper traces developments in the credit risk measurement literature over the last 20 years. The paper is essentially divided into two parts. In the first part the evolution of the literature on the credit-risk measurement of individual loans and portfolios of loans is traced by way of reference to articles appearing in relevant issues of the Journal of Banking and Finance and other publications. In the second part, a new approach built around a mortality risk framework to measuring the risk and returns on loans and bonds is presented. This model is shown to offer some promise in analyzing the risk-return structures of portfolios of credit-risk exposed debt instruments.