On the Malliavin approach to Monte Carlo approximation of conditional expectations

Given a multi-dimensional Markov diffusion X, the Malliavin integration by parts formula provides a family of representations of the conditional expectation E[g(X ₂)|X₁]. The different representations are determined by some localizing functions. We discuss the problem of variance reduction within this family. We characterize an exponential function as the unique integrated mean-square-error minimizer among the class of separable localizing functions. For general localizing functions, we prove existence and uniqueness of the optimal localizing function in a suitable Sobolev space. We also provide a PDE characterization of the optimal solution which allows to draw the following observation : the separable exponential function does not minimize the integrated mean square error, except for the trivial one-dimensional case. We provide an application to a portfolio allocation problem, by use of the dynamic programming principle.Mathematics Subject Classification: 60H07, 65C05, 49-00JEL Classification: G10, C10The authors gratefully acknowledge for the comments raised by an anonymous referee, which helped understanding the existence result of Sect. [4.2] of this paper.     

The effects of social heterogeneity on travel patterns: A replication study

This paper examines differences between the U.S. and Australian urban landscape in terms of the relationship between urban structure and the effectiveness of public transportation. A replication study is undertaken that tests the validated hypothesis from a U.S. study that urban travel corridor social heterogeneity reduces patronage of public transportation because of resident concerns with social composition of passengers and effects on the travel privacy dimension. A causal model is identified for the city of Sydney that specifies enogenous and endogenous variables, as per the U.S. study, which affect bus and rail use. Results do not lead to the acceptance of the hypothesized relationship. The presence of social heterogeneity in Sydney travel corridors does not deter residents within the study corridors from using the bus or train for the journey to work, nor do they appear to affect longer term decisions on car ownership. Bus patronage was shown to be dependent on social heterogeneity factors while rail use was associated with car owning households. These results highlight differences in urban spatial structure and travel patterns between Sydney and cities in the U.S. study, and suggest differential effects of changes in urban spatial structure and policy responses.     

Valentin F. Wagner † 17. XII. 1895 bis 8. V. 1959

Ohne Zusammenfassung     

Chancen und Risiken in den Finanzmärkten

Ohne Zusammenfassung     

On the Term Structure of Default Premia in the Swap and LIBOR Markets

Existing theories of the term structure of swap rates provide an analysis of the Treasury–swap spread based on either a liquidity convenience yield in the Treasury market, or default risk in the swap market. Although these models do not focus on the relation between corporate yields and swap rates (the LIBOR–swap spread), they imply that the term structure of corporate yields and swap rates should be identical. As documented previously (e.g., in Sun, Sundaresan, and Wang (1993)) this is counterfactual. Here, we propose a model of the default risk imbedded in the swap term structure that is able to explain the LIBOR–swap spread. Whereas corporate bonds carry default risk, we argue that swap contracts are free of default risk. Because swaps are indexed on "refreshed"-credit-quality LIBOR rates, the spread between corporate yields and swap rates should capture the market's expectations of the probability of deterioration in credit quality of a corporate bond issuer. We model this feature and use our model to estimate the likelihood of future deterioration in credit quality from the LIBOR–swap spread. The analysis is important because it shows that the term structure of swap rates does not reflect the borrowing cost of a standard LIBOR credit quality issuer. It also has implications for modeling the dynamics of the swap term structure.     

Currency Hedging and Siegel's Paradox: On Black's Universal Hedging Rule*

In an international multicurrency context, with nonstochastic inflation, equilibrium asset pricing models dictate that all investors should hold a combination of their national risk-free bill and the world market portfolio partly hedged against currency risk. We show that the equilibrium hedge ratios are not universal and depend on investors' preferences and relative wealth. So-called universal hedging rules are devoid of solid theoretical underpinning and practical applicability.     

Developing the marketing concept in public accounting firms

As the American Institute of Certified Public Accounts relaxes its practice development restrictions, CPA firms find themselves with a need to develop more aggressive approaches to the markets they serve. This paper focuses on the development of a marketing strategy for an illustrative market, that of small, rapidly-growing high technology firms. Results from a telephone survey of company executives serve as the basis for strategy development. In addition, the evaluation of a small firm and its accounting needs are provided in a hypothetical example to dramatize the conclusions. The results suggest that the burden may be on CPA firms to anticipate, recognize, and meet the accounting needs of their clientele.     

Modelling insurgent-incumbent dynamics: Vector autoregressions,multivariate Markov chains,and the nature of technological competition

The struggle between sail and steam is a long-standing theme in economic history. But this technological competition story has only partly tackled, since most studies have appreciated the rivalry between the two alternative modes of commercial sea carriage in the late 19th century while the early period has remained relatively under-analysed. This paper models the early dynamics between the two capital goods using a vector autoregression approach (VAR) and a Multivariate Markov Chain approach (MMC). We find evidence that the relationship was non-linear, with a strong indication of complementarities and cross-technology learning effects.     

The role of villages in households’ poverty exit: evidence from a multilevel model for rural Vietnam

Vietnam experienced a dramatic drop in overall poverty during the 90s. However, the poverty reduction showed substantial variation across households, villages and regions. Using a multilevel model on panel data from the rural sample of the Vietnam Living Standard Measurement Survey we demonstrate the important role of villages in household poverty exit dynamics. We also show how an analysis of village-level random effects predictions can help targeting of policies to reduce poverty.