International portfolio selection with exchange rate risk: A behavioural portfolio theory perspective

This paper analyzes international portfolio selection with exchange rate risk based on behavioural portfolio theory (BPT). We characterize the conditions under which the BPT problem with a single foreign market has an optimal solution, and show that the optimal portfolio contains the traditional mean–variance efficient portfolio without consideration of exchange rate risk, and an uncorrelated component constructed to hedge against exchange rate risk. We illustrate that the optimal portfolio must be mean–variance efficient with exchange rate risk, while the same is not true from the perspective of local investors unless certain conditions are satisfied. We further establish that international portfolio selection in the BPT with multiple foreign markets consists of two sequential decisions. Investors first select the optimal BPT portfolio in each market, overlooking covariances among markets, and then allocate funds across markets according to a specific rule to achieve mean–variance efficiency or to minimize the loss in efficiency.     

Systemic risk contributions: A credit portfolio approach

We put forward a framework for measuring systemic risk and attributing it to individual banks. Systemic risk is coherently measured as the expected loss to depositors and investors when a systemic event occurs. The risk contributions are calculated so as to ensure a full risk allocation among institutions. Applying our methodology to a panel of 54–86 of the world’s major commercial banks for a 13-year time span with monthly frequency not only allows us to closely match the list of G-SIBs; we can also use individual risk contributions to compute bank-specific surcharges: systemic capital charges as well as countercyclical buffers. We therefore address both dimensions of systemic risk – cross-sectional and time-series – in a single integrated approach. As the analysis of risk drivers confirms, the main focus of macroprudential supervision should be on a solid capital base throughout the financial cycle and de-correlation of banks’ asset values.     

A synthetic factor approach to the estimation of value-at-risk of a portfolio of interest rate swaps

In this paper we decompose the interest rate swap yield curves of 10 major currencies into their common factors and find that the first two factors, interpreted as parallel shift and rotation, explain between 97.1% and 98.6% of the variation in the interest rate swap rates across all 10 currencies. The main contribution of the paper however is that we then model these two factors as simplified synthetic factors so that they may be used to develop an innovative approach to the computation of Value-at-Risk (VaR) for a portfolio of interest rate swaps.     

A chaotic approach to interest rate modelling

This paper presents a new approach to interest rate dynamics. We consider the general family of arbitrage-free positive interest rate models, valid on all time horizons, in the case of a discount bond system driven by a Brownian motion of one or more dimensions. We show that the space of such models admits a canonical mapping to the space of square-integrable Wiener functionals. This is achieved by means of a conditional variance representation for the state price density. The Wiener chaos expansion technique is then used to formulate a systematic analysis of the structure and classification of interest rate models. We show that the specification of a first-chaos model is equivalent to the specification of an admissible initial yield curve. A comprehensive development of the second-chaos interest rate theory is presented in the case of a single Brownian factor, and we show that there is a natural methodology for calibrating the model to at-the-money-forward caplet prices. The factorisable second-chaos models are particularly tractable, and lead to closed-form expressions for options on bonds and for swaptions. In conclusion we outline a general international model for interest rates and foreign exchange, for which each currency admits an associated family of discount bonds, and show that the entire system can be generated by a vector of Wiener functionals.Received: March 2004, Mathematics Subject Classification (2000): 91B28, 91B30, 91B50, 60H07JEL Classification: E43We are grateful to J. Boland, D. Brody, P. Carr, M. Davis, F. Delbaen, D. Filipovi, R. Jarrow, M. Grasselli, P. Hunt, T. Hurd, D. Madan, P. Malliavin, H. Rasmussen and M. Zervos for stimulating discussions. We thank D. Brody, M. Grasselli, T. Hurd and M. Zervos, in particular, for suggesting a number of improvements in the arguments presented here. We are grateful for helpful comments by participants at the Frontiéres en Finance seminar, Paris, May 2002, the Mathematics in Finance conference, Kruger Park, RSA, August 2002, the Imperial College finance seminar, February 2003, the 13th annual Derivative Securities Conference, New York, April 2003, the Analysis of Random Markets Workshop, Banach Center, Warsaw, October 2003 and the Quantitative Methods in Finance Conference, Sydney, December 2003, where this work was presented. LPH acknowledges the hospitality of the Institute for Advanced Study, Princeton, where part of this work was carried out. AR acknowledges financial support from the Department of Mathematics, Kings College London.     

Interest rate risk and optimal design of mortgage instruments

This article develops and analyzes a simple expected utility model for interest rate risk and mortgage choice. The model demonstrates how the risks of interest rate changes should be allocated between borrowers and lenders through varying mortgage payments. In general, we conclude that full protection against interest rate risk, as a normative guideline, is likely to be suboptimal for the typical household. Our results show that the optimal design of adjustable rate mortgages should include an interest rate CAP provision.An earlier version of this article was presented at the American Real Estate and Urban Economics Association Meetings, Atlanta, Georgia, December 27–30, 1989.     

Modelling and forecasting short-term interest rate volatility: A semiparametric approach

This paper employs a semiparametric procedure to estimate the diffusion process of short-term interest rates. The Monte Carlo study shows that the semiparametric approach produces more accurate volatility estimates than models that accommodate asymmetry, level effect and serial dependence in the conditional variance. Moreover, the semiparametric approach yields robust volatility estimates even if the short rate drift function and the underlying innovation distribution are misspecified. Empirical investigation with the U.S. three-month Treasury bill rates suggests that the semiparametric procedure produces superior in-sample and out-of-sample forecast of short rate changes volatility compared with the widely used single-factor diffusion models. This forecast improvement has implications for pricing interest rate derivatives.     

Time-consistency in managing a commodity portfolio: A dynamic risk measure approach

We address the problem of managing a storable commodity portfolio, that includes physical assets and positions in spot and forward markets. The vast amount of capital involved in the acquisition of a power plant or storage facility implies that the financing period stretches over a period of several quarters or years. Hence, an intertemporally consistent way of optimizing the portfolio over the planning horizon is required. We demonstrate the temporal inconsistency of static risk objectives based on final wealth and advocate the validity in our setting of a new class of recursive risk measures introduced by Epstein and Zin [Epstein, G., Zin, S., 1989. Substitution, risk aversion, and the temporal behavior of consumption and asset returns: A theoretical framework. Econometrica, 57 (4) 937–969] and Wang [Wang, T., 2000. A class of dynamic risk measures University of British Columbia]. These risk measures provide important insights on the trade-offs between date-specific risks (i.e., losses occurring at a point in time) and time-duration risks represented by the pair (return, risk) over a planning horizon; in a number of situations, they dramatically improve the efficiency of static risk objectives, as exhibited in numerical examples.     

International portfolio diversification: an ICAPM approach with currency risk

This article investigates international stock market integration in four major developed economies, namely the United States, the Economic and Monetary Union of the European Union, Japan and the United Kingdom, and two Asian emerging, countries namely China and India, over the period from June 1994 to June 2009. To model stock market integration we estimate a dynamic version of the international capital asset pricing model (CAPM) in the absence of purchasing power parity. Conditional variance is modelled via a multivariate GARCH specification. To investigate the evolution of integration overtime we estimate the CAPM in sub-periods. In addition, we connect our results to the timing of world financial crises. Our findings show that the stock markets tend to move in parallel after June of 2002, although from 2002 to 2006 there have not been crises events. These results support the increasing globalization and interdependence of both emerging and developed markets in the recent decade, reducing the benefits of portfolio diversification.     

The closing rate on residential mortgage commitments: An econometric analysis

Mortgage lenders routinely guarantee rates and points for periods of 60 days or more and hedge the inherent interest rate risk by selling the proportion of mortgages expected to close in forward markets. This article presents a model of the decision to close on the mortgage and demonstrates that the estimates of the model increase the precision of closing rate forecasts. The analysis indicates that changes in mortgage rates are important determinants of the closing rate for fixed-rate mortgages (FRM) and adjustable-rate mortgages (ARM). Other important factors include whether the mortgage is for a new purchase, for owner occupancy, and for a single-family house, and what the overall level of mortgage rates and the loan-to-value ratio are and whether the rate guarantee was granted at the application date or later.     

A portfolio balance approach to the Canadian-U.S. exchange rate

An empirical portfolio balance model based on Branson and Henderson [Branson, W. H., & Henderson, D. W. (1985). The specification and influence of assets markets. In: Jones R. W., Kenen, P. B. (Eds.), Handbook of International Economics, Volume 2, Elsevier, Amsterdam] is specified for the Canadian-U.S. exchange rate over the floating exchange rate period. Empirical implementation reveals two cointegrating vectors that closely, although not perfectly, match the home and foreign asset demands of the theoretical model. Furthermore, the exchange rate is important in the error correction process. Finally, although the significance is quantitatively and statistically modest, a simplified version of the empirical model resulting from general-to-specific procedures is able to beat a random walk at some out-of-sample forecast horizons.     

The integrated impact of credit and interest rate risk on banks: A dynamic framework and stress testing application

Credit and interest rate risk are the two most important risks faced by commercial banks in their banking book. In this paper we derive a consistent and comprehensive framework to measure the integrated impact of both risks. By taking account of the repricing characteristics of assets, liabilities and off balance sheet items, we assess the integrated impact of credit and interest rate risk on banks’ economic value and capital adequacy. We then stress test a hypothetical but realistic bank using our framework and show that it is fundamental to measure the impact of credit and interest rate risk jointly.     

The numeraire portfolio: a new perspective on financial theory

The numeraire portfolio, also called the optimal growth portfolio, allows simple derivations of the main results of financial theory. The prices of self financing portfolios, when the optimal growth portfolio is the numeraire, are martingales in the ‘true’ (historical) probability. Given the dynamics of the traded securities, the composition of the numeraire portfolio as well as its value are easily computable. Among its numerous properties, the numeraire portfolio is instantaneously mean variance efficient. This key feature allows a simple derivation of standard continuous time CAPM, CCAPM, APT and contingent claim pricing. Moreover, since the Radon-Nikodym derivatives of the usual martingale measures are very simple functions of the numeraire portfolio, the latter provides a convenient link between the standard Capital Market Theory a la Merton and the probabilistic approach a la Harrison-Kreps-Pliska.     

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.     

Contagion effect on bond portfolio risk measures in a hybrid credit risk model

This paper illustrates how modelling the contagion effect among assets of a given bond portfolio changes the risk perception associated to it. This empirical work is developed in a hybrid credit risk framework that incorporates recovery rate risk. Dependence structures among firms and between external shocks affecting firms together are considered. The presence of correlations among firm leverage ratios and the interrelation between default probabilities and recovery rates produces clusters of defaults with low recovery rates. This has a major impact on standard risk measures such as Value-at-Risk and conditional tail expectation. Consequently, an appropriate measurement of the contagion has a tremendous effect on the capital requirement of many financial institutions.     

Dynamic hedge fund portfolio construction: A semi-parametric approach

In this article, we evaluate alternative optimization frameworks for constructing portfolios of hedge funds. We compare the standard mean–variance optimization model with models based on CVaR, CDaR and Omega, for both conservative and aggressive hedge fund investment strategies. In order to implement the CVaR, CDaR and Omega optimization models, we propose a semi-parametric methodology, which is based on extreme value theory, copula and Monte Carlo simulation. We compare the semi-parametric approach with the standard, non-parametric approach, used to compute CVaR, CDaR and Omega, and the benchmark parametric approach, based on both static and dynamic mean–variance optimization. We report two main findings. The first is that the CVaR, CDaR and Omega models offer a significant improvement in terms of risk-adjusted portfolio performance over the parametric mean–variance model. The second is that semi-parametric estimation of the CVaR, CDaR and Omega models offers a very substantial improvement over non-parametric estimation. Our results are robust to the choice of target return, risk limit and estimation sample size.     

Loss coverage and stress testing mortgage portfolios: A non-parametric approach

This paper outlines the development of a practical approach to simulating a credit loss distribution function and to implementing a stress test exercise focusing on the entire Spanish mortgage portfolio. Specifically, we determine, via regression model, the main factors that explain why households fail to meet their mortgage payment commitments. This allows us to assign individual borrowers’ PDs and to estimate a rating system for the mortgage portfolio. Then, we simulate the empirical distribution function of mortgage loss rates using a Monte-Carlo resampling method, and compare the loss rates from this function with those provided by the Basel II IRB formulas. Finally, we assess, by running a stress exercise, the ability of banks to withstand certain adverse situations. The main result from this exercise is that, in general terms, Basel II IRB regulatory loss coverage offers fairly adequate protection for banks.     

Fixed versus variable rate financing: The influence of borrower,lender, and market characteristics

Previous research has analyzed the problem faced by borrowers who must choose between fixed rate and variable rate loans when each loan carries different cost and risk characteristics and the borrowers face various income and employment prospects. In addition, the existing literature contains theoretical and empirical studies of how lenders react when given the ability to offer both fixed and variable rate financing. This article unifies the two strands of research to develop and test a model of the equilibrium proportion of variable rate lending. Results indicate that factors related to borrower, lender, and market characteristics are significant determinants of the equilibrium proportion of variable rate credit originated.     

Marriage and other risky assets: A portfolio approach

We study the joint impact of gender and marital status on financial investments by testing the hypothesis that marriage represents – in a portfolio framework – a sort of safe asset and that this attribute may change over time. We show that married individuals have a higher propensity to invest in risky assets than single ones, that this marital status gap is stronger for women and that, for women only, it evolves and declines at the end of the sample period. Next we explore a number of possible explanations of the observed gender differences by controlling for background factors that capture the evolution of family and society. We find that both the higher female marital status gap and its time variability vanish for those women who are employed. Our empirical investigation is based on a dataset drawn from the 1993–2006 Bank of Italy Survey of Household Income and Wealth.     

连续加息对保险业发展的影响

连续加息对保险业的冲击主要来自两方面:一是对保险产品收益率的影响,二是对保险资金运用收益率的影响。现在,银行存款利率超过寿险预定利率,其结构性影响十分复杂,需持续谨慎观察。