the public private wage differential in a poor urban economy the occupational structure of wages is generally more compressed in high than in low income countries the role of non market forces in determining the structure of wages is of interest for reasons of allocative efficiency as well as for distributional concerns this paper considers how wage differentials may be generated between the public and private sectors of a developing economy data from a 1971 household survey of the tanzanian urban wage labor force are used to determine the pattern of wage differences across employer groups after standardizing by worker characteristics public sector employees are found to have earned a substantial wage premium over workers employed in the private sector the non market character of these differentials is examined in light of a number of hypotheses on public sector wage determination

parastatal pay policy in africa abstract public enterprises have grown to represent a significant share of modern sector employment in many african economies with wage and employment issues near the top of the policy agenda in africa attention should be given to public enterprise compensation and employment policies after describing the institutions which govern public enterprise pay in a number of sub saharan countries the paper considers the policy dilemma in choosing between the two basic alternative pay setting regimes for public enterprise enterprise wage autonomy versus unified salary scales with the civil service

lp modeling for asset liability management a survey of choices and simplifications dynamic linear programming lp models for asset liability management alm are quite powerful and flexible but face two challenges 1 many modeling choices not all consistent with one another or with finance theory and 2 solution difficulties due to the large number of scenarios obtained from standard interest rate models we first survey these modeling choices with a view to help researchers make self consistent choices next we review how the dynamic lp model for alm and the representation of uncertainty therein have been simplified in the past to motivate new or hybrid models emphasizing tractability to this end we review existing static lp models as extreme modeling simplifications and aggregation as a simplification of uncertainty

a switching regression model for wage determinants in the public and private sectors of a developing country governments in less developed countries face severe budgetary constraints given that public sector employment is a large part of modern sector employment the government wage bill h as come under increased scrutiny the central question is how do gove rnment wages compare with those in the private sector in this paper the authors develop and estimate a model to answer this question an important aspect of this model is the endogenous treatment of sector choice the estimation results full information maximum likelihood sound a strong warning against the use of ordinary least squares est imates that are based on sector specific samples data are from the i vory coast copyright 1988 by mit press

pricing credit derivatives with rating transitions we present a model for pricing risky debt and valuing credit derivatives that is easily calibrated to existing variables our approach expands a classical term structure model to allow for multiple rating classes of debt the framework has two salient features 1 it uses a rating transition matrix as the driver for the default process and 2 the entire set of rating categories is calibrated jointly which allows arbitrage free restrictions across rating classes as a bond migrates among them we illustrate the approach by applying it to price credit sensitive notes that have coupon payments linked to the rating of the underlying credit

livelihoods and poverty the role of migration a critical review of the migration literature this review of the literature concludes that development studies have paid insufficient attention to labour migration and makes a plea to integrate analyses of migration within those of agricultural and rural development it emphasises that population mobility is much more common than is often assumed and that this has been so throughout human history in fact available material suggests that it is as likely that population mobility has decreased as that it has increased a review of empirical studies shows that it may not be possible to generalise about the characteristics of migrants or about the effects of migration on broader development inequality or poverty the review concludes that given the importance of migration for the rural livelihoods of many people policies should be supportive of population mobility and possibilities should be explored to enhance the positive effects of migration

being good while being bad social responsibility and the international diversification of us firms this paper contributes to the discussion on international diversification and corporate social responsibility csr by suggesting that firms can be simultaneously socially responsible and socially irresponsible to test our assertions we analyze data from 222 publicly traded us firms from 1993 to 2003 the findings support our hypotheses and have significant implications for the way in which we conceptualize csr

dynamic models for fixed income portfolio management under uncertainty abstract we develop multi period dynamic models for fixed income portfolio management under uncertainty using multi stage stochastic programming with recourse the models integrate the prescriptive stochastic programs with descriptive monte carlo simulation models of the term structure of interest rates extensive validation experiments are carried out to establish the effectiveness of the models in hedging against uncertainty and to assess their performance vis a vis single period models an application to tracking the salomon brothers mortgage index is reported with very encouraging results results that establish the efficacy of the models in hedging against out of sample scenarios are also reported for an application from money management the multi period models outperform classical models based on portfolio immunization and single period models

migrants savings the probability of return migration and migrants performance this paper highlights a difference between migrants and the native born namely a positive probability of return migration the analysis demonstrates that this probability results in migrants saving more than comparable native born this differential may explain why even if all workers are perfectly homogeneous in skills migrants often outperform the native born in the receiving economy excerpt

comparing earnings profiles in urban areas of an ldc rural to urban migrants vs native workers abstract we use tanzanian data to test a recently proposed hypothesis that rural to urban migrants have an incentive to supply greater work effort than native urban workers because of the migrants positive probability of returning to the low wage rural areas we treat the choice between public and private sector employment as endogenous and for theoretical and empirical reasons distinguish migrants with access to rural land from those without access our results show that migrants in both sectors face lower initial wage offers than native urban workers but the wage gap is eliminated within a decade or less and thereafter migrants surpass the wage offers of native workers

continuous time methods in finance a review and an assessment i survey and assess the development of continuous time methods in finance during the last 30 years the subperiod 1969 to 1980 saw a dizzying pace of development with seminal ideas in derivatives securities pricing term structure theory asset pricing and optimal consumption and portfolio choices during the period 1981 to 1999 the theory has been extended and modified to better explain empirical regularities in various subfields of finance this latter subperiod has seen significant progress in econometric theory computational and estimation methods to test and implement continuous time models capital market frictions and bargaining issues are being increasingly incorporated in continuous time theory the roots of modern continuous time methods in finance can be traced back to the seminal contributions of merton 1969 1971 1973b in the late 1960s and early 1970s merton 1969 pioneered the use of continuous time modeling in financial economics by formulating the intertemporal consumption and portfolio choice problem of an investor in a stochastic dynamic programming setting merton 1973b also showed how such a framework can be used to develop equilibrium asset pricing implications thereby significantly extending the asset pricing theory to richer dynamic settings and expanding the scope of applications of continuous time methods to study problems in financial economics 1 within a span of about 30 years from the publication of merton s inf luential papers continuous time methods have become an integral part of financial economics indeed in certain core areas in finance such as e g asset pricing derivatives valuation term structure theory and portfolio selection continuoustime methods have proved to be the most attractive way to conduct research and gain economic intuition the continuous time approach in these areas has produced models with a rich variety of testable implications the econometric theory for testing continuous time models has made rapid strides in the last decade and has thus kept pace with the impressive progress on the theoretical front one hopes that the actual empirical investigations and estimation using the new procedures will follow suit soon

using the black derman toy interest rate model for portfolio optimization abstract no arbitrage interest rate models are designed to be consistent with the current term structure of interest rates the diffusion of the interest rates is often approximated with a tree in which the scenario dependent fair price of any security is calculated as the present value of the risk neutral expectation by backward induction to use this tree in a portfolio optimization context it is necessary to account for the so called market price of risk in this paper we present a method to change the conditional probabilities in the black derman toy model to the physical or real measure including the market price of risk and explore the economic implications for expected spot rates and for expected bond returns

pricing and hedging interest rate options evidence from cap floor markets we examine the pricing and hedging performance of interest rate option pricing models using dailydata on us dollar cap and floor prices across both strike rates and maturities our results show that fitting the skew of the underlying interest rate probability distribution provides accurate pricing results within a one factor framework however for hedging performance introducing a second stochastic factor is more important than fitting the skew of the underlying distribution this constitutes evidence against claims in the literature that correctly specified and calibrated one factor models could replace multi factor models for consistent pricing and hedging of interest rate contingent claims 2004 elsevier b v all rights reserved

throwing away a billion dollars the cost of suboptimal exercise strategies in the swaptions market abstract this paper studies the costs of applying single factor exercise strategies to american swap options when the term structure is actually driven by multiple factors using a multifactor string market model of the term structure we find that even when single factor models are recalibrated to match the market at every exercise date the exercise strategies they imply can be suboptimal based on estimates of notional amounts outstanding the total present value costs of following single factor strategies could be several billion dollars these results illustrate the importance of using well specified term structure models

the term structure of interest rates with housing abstract this paper develops a general equilibrium model to study the link between the amount of capital invested in housing assets and the term structure of interest rates in the model the production of housing assets is irreversible and housing assets can be used as collateral for borrowing funds agents decisions about consumption and investments in housing and non housing assets generate a time varying market price of risk that drives the dynamics of the term structure the calibration to u s data using the simulated method of moments technique captures the dynamics of consumption and the short and long term interest rates

a dynamic model for the forward curve this article develops and estimates a dynamic arbitrage free model of the current forward curve as the sum of i an unconditional component ii a maturity specific component and iii a date specific component the model combines features of the preferred habitat model the expectations hypothesis et and affine yield curve models it permits a class of low parameter multiple state variable dynamic models for the forward curve we show how to construct alternative parametric examples of the three components from a sum of exponential functions verify that the resulting forward curves satisfy the heath jarrow morton hjm conditions and derive the risk neutral dynamics for the purpose of pricing interest rate derivatives we select a model from alternative affine examples that are fitted to the fama bliss treasury data over an initial training period and use it to generate out of sample forecasts for forward rates and yields for forecast horizons of 6 months or longer the forecasts of this model significantly outperform those from common benchmark models jel c53 e43 e47 the structure of forward rates for fixed maturity loans to begin at various dates in the future can be inferred from the prices of treasury securities or directly observed from the extremely active eurodollar futures market the constellation of these rates or of the related yields plays a central role intheallocationofcapital therandombehaviorofthis yieldcurve or the relationship between the yields and the term to maturity is a subject of considerable theoretical and empirical study

discretized reality and spurious profits in stochastic programming models for asset liability management in the literature on stochastic programming models for practical portfolio investment problems relatively little attention has been devoted to the question how the necessarily approximate description of the asset price uncertainty in these models influences the optimal solution in this paper we will show that it is important that asset prices in such a description are arbitrage free descriptions which have been suggested in the literature are often inconsistent with observed market prices and or use sampling to obtain a set of scenarios about the future we will show that this effectively introduces arbitrage opportunities in the optimization model for an investor who cannot exploit arbitrage opportunities directly because of market imperfections and trading restrictions we will illustrate that the presence of such arbitrage opportunities may cause substantial biases in the optimal investment strategy

a one factor model of interest rates and its application to treasury bond options 1990 a one factor model of interest rates and its application to treasury bond options financial analysts journal vol 46 no 1 pp 33 39

convertible bonds model value attribution and analytics convertible bonds provide investors an option to convert the bond into the underlying equity for this reason a convertible bond is exposed to both equity and interest rate risk incorporating these two sources of risk into the model is particularly important for callable issues in this study a two factor model is used to analyze a sample of bonds the model shows that the correlation of stock risk and interest rate risk may affect convertible bond prices significantly the bond pricing model also provides portfolio analytics and can decompose a convertible bond into its basic components the stock and bonds with different maturities this approach enables an investor to implement a more precise hedging strategy than is possible using only delta

the analysis and valuation of interest rate options abstract this paper provides a simple alternative model for the valuation of european style interest rate options the assumption that drives the hedging argument in the model is that the forward prices of bonds follow an arbitrary two state process later this assumption is made more specific by postulating that the discount on a zero coupon bond follows a multiplicative binomial process in contrast to the black scholes assumption applied to zero coupon bonds the limiting distribution of this process has the attractive features that the zero bond price has a natural barrier at unity thus precluding negative interest rates and that the bond price is negatively skewed the model is used to price interest rate options in general and interest rate caps and floors in particular the model is then generalized and applied to european style options on bonds a relationship is established between options on swaps and options on coupon bonds the generalized model then provides a computationally simple formula closely related to the black scholes formula for the valuation of european style options on swaps

a model for designing callable bonds and its solution using tabu search abstract we formulate the problem of designing callable bonds as a non linear global optimization problem the data of the model are obtained from simulations of holding period returns of a given bond design which are used to compute a certainty equivalent return viz some target assets the design specifications of the callable bond are then adjusted so that the certainty equivalent return is maximized the resulting problem is multi modal and a tabu search procedure implemented on a distributed network of workstations is used to optimize the bond design the model is compared with the classical portfolio immunization model and the tabu search solution technique is compared with simulated annealing for solving the global optimization program it is shown that the global optimization model yields higher returns than portfolio immunization it is also shown that tabu search is computationally more efficient than simulated annealing in solving the model and it produces better solutions

on the suboptimality of single factor exercise strategies for bermudan swaptions abstract this paper resolves the disagreement between longstaff et al 2001 journal of finance economics 62 39 66 and andersen and andreasen 2001 journal of financial economics 62 3 37 over the effectiveness of the common business practice of using best fit single factor term structure models to deduce exercise strategies of bermudan swaptions i examine the cost of using recalibrated single factor models to determine the exercise strategy for bermudan swaptions in a multifactor world i show that single factor exercise strategies applied in a multifactor world only give rise to economically insignificant losses furthermore i find that the conditional model risk as defined in longstaff et al 2001 journal of finance economics 62 39 66 is statistically insignificant given the number of observations additional tests using the primal dual algorithm of andersen and broadie 2004 management science 50 9 indicate that losses found in longstaff et al 2001 journal of finance economics 62 39 66 cannot as claimed be ascribed to the number of factors

from data to model and back to data a bond portfolio management problem abstract the bond portfolio management problem is formulated as a multiperiod stochastic program using interest rate scenarios the scenarios are sampled from the binomial lattice from a black derman toy model the paper analyzes the sensitivity of the solution of the resulting large scale mathematical program with respect to the model inputs the numerical results are for the italian bond market

the probability of return migration migrants work effort and migrants performance abstract this paper demonstrates that differences in earnings between migrants and the native population may reflect differences in incentives rather than differences in characteristics the analysis indicates that in the presence of a positive probability of return migration migrants work effort is higher than that of comparable native born workers this differential may explain why even if all workers are perfectly homogeneous in skills migrants often outperform the native born workers in the receiving economy

modeling the stochastic behavior of short term interest rates pricing implications for discount bonds abstract this paper models the stochastic behavior of short term interest rates and determines the correct specification of the drift and diffusion functions of the spot rate process a wide variety of one factor diffusion and two factor stochastic volatility models is compared in terms of their ability to capture the dynamics of interest rate volatility the empirical evidence on the one three and six month eurodollar deposit rates indicates that a new class of models with stochastic volatility is better than the single factor diffusion models in forecasting the future volatility of interest rate changes the paper extends the one factor bdt term structure model to a two factor setting and presents the pricing implications for discount bonds monte carlo simulation results for the implied yields of three and six month zero coupon bonds imply that incorporating the so called level and garch effects in volatility improves the pricing performance of the interest rate models

one factor interest rate models and the valuation of interest rate derivative securities this paper compares different approaches to developing arbitrage free models of the term structure it presents a numerical procedure that can be used to construct a wide range of one factor models of the short rate that are both markov and consistent with the initial term structure of interest rates

the intersection of market and credit risk abstract economic theory tells us that market and credit risks are intrinsically related to each other and not separable we describe the two main approaches to pricing credit risky instruments the structural approach and the reduced form approach it is argued that the standard approaches to credit risk management creditmetrics creditrisk and kmv are of limited value when applied to portfolios of interest rate sensitive instruments and in measuring market and credit risk empirically returns on high yield bonds have a higher correlation with equity index returns and a lower correlation with treasury bond index returns than do low yield bonds also macro economic variables appear to influence the aggregate rate of business failures the creditmetrics creditrisk and kmv methodologies cannot reproduce these empirical observations given their constant interest rate assumption however we can incorporate these empirical observations into the reduced form of jarrow and turnbull 1995b drawing the analogy risk 5 63 70 model here default probabilities are correlated due to their dependence on common economic factors default risk and recovery rate uncertainty may not be the sole determinants of the credit spread we show how to incorporate a convenience yield as one of the determinants of the credit spread for credit risk management the time horizon is typically one year or longer this has two important implications since the standard approximations do not apply over a one year horizon first we must use pricing models for risk management some practitioners have taken a different approach than academics in the pricing of credit risky bonds in the event of default a bond holder is legally entitled to accrued interest plus principal we discuss the implications of this fact for pricing second it is necessary to keep track of two probability measures the martingale probability for pricing and the natural probability for value at risk we discuss the benefits of keeping track of these two measures

integrated simulation and optimization models for tracking indices of fixed income securities increasing performance pressures on fixed income managers have led to a search for new and creative ways to add to portfolio returns the largest pension plan sponsors insurance companies foundations and money management firms are using indexed portfolios as their fixed income assets management strategies since the late 1970s tracking a fixed income index is a difficult task due to transaction costs portfolio size and diversification restrictions liquidity requirements bid ask spreads etc this paper develops an integrated simulation and optimization approach for tracking fixed income indices the model was implemented at metropolitan life insurance company we introduce a simulation model for generating scenarios of holding period returns of the securities in the index then we develop optimization models to select a portfolio that tracks the index the models penalize downside deviations of the portfolio return from the index the developed framework is used to track the salomon brothers mortgag

an integrated pricing model for defaultable loans and bonds abstract in recent years credit risk has played a key role in risk management issues practitioners academics and regulators have been fully involved in the process of developing studying and analysing credit risk models in order to find the elements which characterize a sound risk management system in this paper we present an integrated model based on a reduced pricing approach for market and credit risk its main features are those of being mark to market and that the spread term structure by rating class is contingent on the seniority of debt within an arbitrage free framework we introduce issues such as the integration of market and credit risk the use of stochastic recovery rates and recovery by seniority moreover we will characterize default risk by estimating migration risk through a mortality rate actuarial based approach the resultant probabilities will be the base for determining multi period risk neutral transition probability that allow pricing of risky debt in the trading and banking book

an empirical comparison of forward rate and spot rate models for valuing interest rate options our main goal is to investigate the question of which interest rate options valuation models are better suited to support the management of interest rate risk we use the german market to test seven spot and forward rate models with one and two factors for interest rate warrants for the period from 1990 to 1993 we identify a one factor forward rate model and two spot rate models with two factors that are not significantly outperformed by any of the other four models further rankings are possible if additional criteria are applied

pricing derivatives on financial securities subject to credit risk this article provides a new methodology for pricing and hedging derivative securities involving credit risk two types of credit risks are considered the first is where the asset underlying the derivative security may default the second is where the writer of the derivative security may default we apply the foreign currency analogy of jarrow and turnbull 1991 to decompose the dollar payoff from a risky security into a certain payoff and a spot exchange rate arbitrage free valuation techniques are then employed this methodology can be applied to corporate debt and over the counter derivatives such as swaps and caps the purpose of this article is to provide a new theory for pricing and hedging derivative securities involving credit risk two sources of credit risk are identified and analyzed the first is where the asset underlying the derivative security may default paying off less than promised this is the case for example with imbedded options on corporate debt the second is the credit risk introduced by the writer of the derivative security who may also default examples include over the counter writers of options on eurodollar futures swaps and swaptions for pricing derivative securities involving credit risk there are currently two approaches the first views these derivatives as contingent claims not on the financial securities themselves but as compound options on the assets underlying the financial securities this is the case for example with the pricing of imbedded options on corporate debt see merton 1974 1977 black and cox 1976 ho and singer 1982 chance 1990 and kim ramaswamy and sundaresan 1993 or the pricing of vulnerable options see johnson and stulz 1987 in practice however this valuation methodology is difficult to use first the assets underlying the financial security are often not tradeable and therefore their values are not observable this makes application of the theory and estimation of the relevant parameters problematic second as in the case of corporate debt all of the other liabilities of the firm senior to the corporate debt must first and simultaneously be valued this generates significant computational difficulties as a result this approach has not

the valuation of complex derivatives by major investment firms empirical evidence this article examines the auction of a portfolio of collateralized mortgage obligations cmos to major broker dealers and institutional investors the unique data set allows us to analyze a number of important empirical questions related to the valuation of cmos by the bidders and the elasticity of demand for the securities the results reveal that the valuations differ substantially implying a significant elasticity of demand this article is designed to shed light on two related questions first it extends the work of bagwell 1991 1992 brown and ryngaert 1990 and bradley desai and kim 1988 among others on shareholder heterogeneity and the elasticity of the demand for financial assets to date the empirical research on investor heterogeneity has focused on common stock this article supplements previous work by examining an auction of another class of securities complex collateralized mortgage obligations cmos to major securities dealers and institutional investors second it provides perspective on fixed income valuation models in the spirit of cox ingersoll and ross 1985 and black derman and toy 1990 virtually all of these models even those that specify relatively complex interest rate processes assume homogeneous beliefs this implies that within the constraints imposed by estimation error sophisticated investors should place equal values on fixed income securities bagwell observes that investors can be heterogeneous along several dimensions first heterogeneity can be induced by tax rules to the extent that different investors are taxed in different ways their demand for securities will be affected second transaction costs can cause heterogeneity by driving a wedge between buyers sellers and owners of a security third investors can differ in their assessments of the value of a security either because they possess different information or because they analyze that information in different ways fourth investors can face different nontradeable risks and thus can have different assessments of the value of a security depending on how it interacts with these risks finally it has been suggested by lee shleifer and thaler 1991 among others that investors may differ for idio

a switching regression model of public private sector wage differentials in peru 1985 86 this article examines the combined impact of the employment guarantee for graduates and public sector compensation policies on the egyptian labor market besides contributing to an unsustainable rate of growth in the government labor force these

a stochastic programming model for money management abstract portfolio managers in the new fixed income securities have to cope with various forms of uncertainty in addition to the usual interest rate changes uncertainy in the timing and amount of cashflows changes in the default and other risk premia and so on complicate the portfolio manager s problem we develop here a multi period dynamic portfolio optimization model to address this problem the model specifies a sequence of investment decisions over time that maximize the expected utility of return at the end of the planning horizon the model is a two stage stochastic program with recourse the dynamics of interest rates cashflow uncertainty and liquidity default and other risk premia are explicitly modeled through postulated scenarios simulation procedures are developed to generate these scenarios the optimization models are then integrated with the simulation procedures extensive validation experiments are carried out to establish the effectiveness of the model in dealing with uncertainty in particular the model is compared against the popular portfolio immunization strategy and against a portfolio based on mean absolute deviation optimization

dynamic models of the term structure in the past 25 years tremendous progress has been made in modeling the dynamics of the term structure of interest rates which play an instrumental role in determining prices and hedging portfolios of fixed income derivative securities this article reviews the theoretical development of the dynamic models of the default free term structure and their applications in pricing interest rate options classic models sometimes termed equilibrium models and their multifactor extensions are outlined these models provide clear economic intuitions connecting the term structure with economic fundamentals they also lay a foundation for the framework of the arbitrage models that price interest rate derivatives on the basis of the market prices of bonds this framework has been expanded and enriched by recent advances in directly modeling observable market rates through the market models and in incorporating an internally consistent correlation structure through the infinite dimensional models

a cyclical square root model for the term structure of interest rates this paper presents a cyclical square root model for the term structure of interest rates assuming that the spot rate converges to a certain time dependent long term level this model incorporates the fact that the interest rate volatility depends on the interest rate level and specifies the mean reversion level and the interest rate volatility using harmonic oscillators in this way we incorporate a good deal of flexibility and provide a high analytical tractability under these assumptions we compute closed form expressions for the values of different fixed income and interest rate derivatives finally we analyze the empirical performance of the cyclical model versus that proposed in cox et al 1985 and show that it outperforms this benchmark providing a better fitting to market data

a multifactor spot rate model for the pricing of interest rate derivatives we propose a multifactor model in which the spot rate libor follows a lognormal process with a stochastic conditional mean under the risk neutral measure in addition to the spot rate factor the second factor is related to the premium of the first futures rate over the spot libor similarly the third factor is related to the premium of the second futures rate over the first futures rate we calibrate the model to the initial term structure of futures rates and to the implied volatilities of interest rate caplets we then apply the model to price interest rate derivatives such as european and bermudan style swaptions and yieldspread options the model can be employed to price more complex interest rate derivatives such as path dependent derivatives or multi currency dependent derivatives because of its markovian property

on the optimality of path dependent structured funds the cost of standardization abstract this paper examines the suitability of an important class of standard financial structured products namely those whose performances are based on smoothing the return of a given risky underlying asset while providing a guarantee at maturity using various assumptions about the customers attitudes towards risk we show that such standardized products are not optimal even if the financial market volatility is constant as a by product we provide in particular the optimal portfolio value in the regret rejoice framework to go further with the notion of aversion of getting a return smaller than the risk free one using the notion of compensating variation we determine for the first time the monetary losses of providing these standardized products instead of the optimal ones to the customers we show that these monetary losses can be very significant when the volatility of the risky asset is stochastic from the operational point of view such results highly suggest to trade on the volatility index vix and or to introduce derivatives written on it when selling standardized funds in order to better meet investors needs and preferences

the valuation of options on coupon bonds abstract we derive simple closed form expressions for european options on coupon bonds using the general equilibrium term structure framework of cox ingersoll and ross the properties of these options are very different from those implied by the black scholes model for example bond call and put values can move in the same direction as the value of the underlying bond changes this has important implications for hedging interest rate risk with bond options furthermore bond option values can be decreasing functions of interest rate volatility as well as their time to expiration we also examine the properties of american bond options

an analysis of public and private sector wages allowing for endogenous choices of both government and union status a general selection model is estimated in which workers select across four labor markets private nonunion private union public nonunion and public union evidence is found of positive selection bias in the private nonunion sector and of negative selection bias in the public union sector union wage differentials in the public and private sectors as well as public private wage differentials are then calculated two different types of wage differentials are contrasted we discuss when it is appropriate to use each type of differential

discounting the distant future how much does model selection affect the certainty equivalent rate evaluating investment with long term consequences using discount rates that decline with the time horizon declining discount rates of ddrs means that future welfare changes are of greater consequence in present value terms recent work in this area has turned towards operationalising the theory and establishing a schedule of ddrs for use in cost benefit analysis using us data we make the following points concerning this transition i model selectionhas important implications for operationalising a theory of ddrs that depends upon uncertainty ii misspecification testing naturally leads to employing models that account for changes in the interest reat generating medanism lastly we provide an analysis of the policy implications of ddrs in the context of climate change for the us and show that the use of a state space model can increase valuations by 150 compared to conventional constant discounting

capturing the correlations of fixed income instruments this paper develops a framework for managing portfolios of fixed income instruments based on traditional principles from the equities market i e based on diversification it shows through an analysis of the high yield bond market over the period 1987 to 1991 that fixed income prices could be highly correlated these correlations can be quantified and integrated in a systematic way in an asset liability management framework for vanishing fixed income securities however we cannot resort to statistical analysis of historical data in order to quantify correlations the paper develops a forward looking simulation procedure for capturing correlations applications are illustrated for examples from high yield bonds and mortgage backed securities the superiority of the proposed approach over the traditional portfolio immunization techniques is demonstrated in the context of funding an insurance liability stream with mortgage instruments

pricing interest rate derivatives a general approach the relationship between affine stochastic processes and bond pricing equations in exponential term structure models has been well established we connect this result to the pricing of interest rate derivatives if the term structure model is exponential affine then there is a linkage between the bond pricing solution and the prices of many widely traded interest rate derivative securities our results apply to m factor processes with n diffusions and l jump processes the pricing solutions require at most a single numerical integral making the model easy to implement we discuss many options that yield solutions using the methods of the article

pricing interest rate derivative securities this article shows that the one state variableinterest rate models of vasicek 1977 and cox ingersoll and ross 1985b can be extended sothat they are consistent with both the current termstructure of interest rates and either the currentvolatilities of all spot interest rates or the currentvolatilities of all forward interest rates theextended vasicek model is shown to be very tracta ble analytically the article compares option pricesobtained using the extended vasicek model withthose obtained using a number of other models