Comparative Analyses of Expected Shortfall and Value-at-Risk (2): Expected Utility Maximization and Tail Risk

We compare expected shortfall and value-at-risk (VaR) in terms of consistency with expected utility maximization and elimination of tail risk. We use the concept of stochastic dominance in studying these two aspects of risk measures. We conclude that expected shortfall is more applicable than VaR in those two aspects. Expected shortfall is consistent with expected utility maximization and is free of tail risk, under more lenient conditions than VaR.

On the Validity of Value-at-Risk: Comparative Analyses with Expected Shortfall

Value-at-risk (VaR) has become a standard measure used in financial risk management due to its conceptual simplicity, computational facility, and ready applicability. However, many authors claim that VaR has several conceptual problems. Artzner et al. (1997, 1999), for example, have cited the following shortcomings of VaR. (1) VaR measures only percentiles of profit-loss distributions, and thus disregards any loss beyond the VaR level ("tail risk"), and (2) VaR is not coherent since it is not sub-additive. To alleviate the problems inherent in VaR, the use of expected shortfall is proposed. In this paper, we provide an overview of studies comparing VaR and expected shortfall to draw practical implications for financial risk management. In particular, we illustrate how tail risk can bring serious practical problems in some cases.

Research toward the Practical Application of Liquidity Risk Evaluation Methods

This paper proposes a practical framework for the quantification of Liquidity-adjusted Value at Risk ("L-VaR") incorporating the market liquidity of financial products. This framework incorporates the mechanism of the market impact caused by the investor's own dealings through adjusting Value-at-Risk according to the level of market liquidity and the scale of the investor's position. Specifically, the optimal execution strategy for liquidating the investor's entire position is first calculated taking the market impact into account. Then the maximum loss that may be incurred by price fluctuations under optimal execution strategy is calculated as L-VaR. This paper presents a specific model providing a closed-form solution for calculating L-VaR, and examines whether this framework can be applied to the practices of financial risk management by calculating numerical examples. It also demonstrates that this L-VaR calculation framework may be applied under more general conditions, such as (1) when the market impact is uncertain, (2) when the investor's portfolio consists of multiple financial assets, and (3) when there is a non-linear relationship between the market impact and the trading volume.

Comparative Analyses of Expected Shortfall and Value-at-Risk: Their Estimation Error, Decomposition, and Optimization

We compare expected shortfall with value-at-risk (VaR) in three aspects: estimation errors, decomposition into risk factors, and optimization. We describe the advantages and the disadvantages of expected shortfall over VaR. We show that expected shortfall is easily decomposed and optimized while VaR is not. We also show that expected shortfall needs a larger size of sample than VaR for the same level of accuracy.

Comparative Analyses of Expected Shortfall and Value-at-Risk (3): Their Validity under Market Stress

In this paper, we compare value-at-risk (VaR) and expected shortfall under market stress. Assuming that the multivariate extreme value distribution represents asset returns under market stress, we simulate asset returns with this distribution. With these simulated asset returns, we examine whether market stress affects the properties of VaR and expected shortfall. Our findings are as follows. First, VaR and expected shortfall may underestimate the risk of securities with fat- tailed properties and a high potential for large losses. Second, VaR and expected shortfall may both disregard the tail dependence of asset returns. Third, expected shortfall has less of a problem in disregarding the fat tails and the tail dependence than VaR does.

On the Risk Capital Framework of Financial Institutions

In this paper, we consider the risk capital framework adopted by financial institutions. Specifically, we review the recent literature on this issue, and clarify the economic assumptions behind this framework. Based on these observations, we then develop a simple model for analyzing the economic implications of this framework. The main implications are as follows. First, risk capital allocations are theoretically unnecessary without deadweight costs for raising capital, which are not usually assumed in the business practices of financial institutions. Second, the risk-adjusted rate of return is redundant as it provides no additional information beyond the net present value. Third, risk capital allocation is intrinsically difficult because it is hard to incorporate the correlations among asset returns.

Aportes para el análisis de los conflictos de tomas de tierras : Relaciones entre políticas estatales y experiencias concretas

La propuesta de este trabajo es presentar una aproximación al análisis de algunas experiencias de tomas de tierras y sus relaciones con el Estado. Retomando líneas de investigación previamente desarrolladas, nos proponemos indagar ciertas formas estatales de intervención en los conflictos de tomas de tierras en las ciudades de Fiske Menuco (Gral. Roca) y Cipolletti, en el periodo 2006 y 2009.Facultad de Humanidades y Ciencias de la Educació

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