Analysis of the volatility’s dependency structure during the subprime crisis

In this article, we test the hypothesis of contagion amongst sectors within the United States’ economy during the subprime crisis. The econometric methodology applied here is based on the dynamic conditional correlation model proposed by Engle (2002). Further, we applied several Lagrange multiplier (LM)-robust tests to test whether there were structural breaks in series’ dependency structures during the period of interest. Events theoretically classified as relevant to the crisis upshots as well as the interactions between the moments of the series were used as indicator functions to the referred structural breaks. The main conclusion of this study is that one can indeed observe contagion within almost all pairs of sectors’ indices. Thus, we conclude that the dependency structure of the sectors of interest has faced structural changes during the years of 2007 and 2008. Hence, diversification strategies as well as the risk analysis inherent to the portfolios’ management may have been drastically affected.     

The Legislator as Political Entrepreneur: Investment in Political Capital

This paper applies the standard Austrian theory of capital investment to the standard interest group model of legislator behavior. Distinguishing between reputational capital and representative capital as interdependent forms of political capital, I argue that legislator behavior (specifically roll call voting) can be explained as entrepreneurial investment in political capital under uncertainty. I discuss several examples in which this approach can potentially add predictive power regarding legislative voting.     

Exchange traded funds: leverage and liquidity

This paper examines the differences between leveraged and unleveraged Exchange Traded Funds (ETFs), particularly for liquidity and volatility characteristics. The impact of leverage on intraday liquidity (spread and depth) is analysed in two periods – one of normal volatility and the other of abnormal/high volatility. There is a significant difference in spread and depth of leveraged and unleveraged ETFs in periods of both normal volatility and high volatility; however, this difference is more pronounced in higher volatility periods. In high volatility periods, liquidity typically diminishes in all ETFs, and this is even more so for the leveraged ETFs. When leveraged ETFs are segregated into multiples based on their power to replicate the underlying benchmark (i.e. multiples of ?3, ?2, ?1, 2, 3), the difference in spreads between normal and high volatility periods is typically larger. The double-leveraged ETF has the most significant difference between the positive and negative counter parts. However, the relationship in the progression of the multiples does not change linearly to correspond with the level of volatility. This may be due to the nonlinear relation between volume and volatility. We shed light on the magnification effect of financial leverage on microstructure of the ETFs.     

What drives idiosyncratic volatility over time?

We document the patterns of market-wide and firm-specific volatility in the Portuguese stock market over the 1991–2005 period and test several explanations for the behavior of firm-level idiosyncratic volatility. Unlike previous studies we find no evidence of a statistically significant rise in firm-specific volatility. On the contrary, the ratio of firm-specific risk to total risk slightly decreases. We show that this result stems from new listings of large privatized companies that display lower firm-specific risk. Our findings are consistent with the idea that changes in idiosyncratic volatility are related to changes in the composition of the market.

Stochastic better-reply dynamics in finite games

In this paper, we analyze a model where individuals from finite populations are repeatedly drawn to play a finite game and in every period choose a weakly better reply to a sample distribution from a finite history of past play. For all finite games and sufficiently incomplete information, we prove convergence to minimal sets closed under better replies. This result complements previous findings in a deterministic continuous-time framework and implies convergence to strict Nash equilibria in many well-known classes of games.     

行为金融学的研究现状与展望

由心理学家和金融学家共同发展起来的行为金融学越来越引人注目,它以前景理论和各种行为金融模型为代表性成果,能有效分析金融市场中由于心理因素引起的投资者失误偏差和市场异象,是现代金融学理论的有益补充。未来的行为金融学如想成为现代金融理论体系的中心,或作为一门单独学科而存在,必须形成统一的理论基础、严密的分析范式、明确的研究主线、研究对象和研究方法以及建立新的基于行为的核心模型。     

Sensitivity analysis of efficiency rankings to distributional assumptions: applications to Japanese water utilities

This article examines the robustness of efficiency score rankings across four distributional assumptions for trans-log stochastic production-frontier models, using data from 1221 Japanese water utilities (for 2004 and 2005). One-sided error terms considered include the half-normal, truncated normal, exponential and gamma distributions. Results are compared for homoscedastic and doubly heteroscedastic models, where we also introduce a doubly heteroscedastic variable mean model, and examine the sensitivity of the nested models to a stronger heteroscedasticity correction for the one-sided error component. The results support three conclusions regarding the sensitivity of efficiency rankings to distributional assumptions. When four standard distributional assumptions are applied to a homoscedastic stochastic frontier model, the efficiency rankings are quite consistent. When those assumptions are applied to a doubly heteroscedastic stochastic frontier model, the efficiency rankings are consistent when proper and sufficient arguments for the variance functions are included in the model. When a more general model, like a variable mean model is estimated, efficiency rankings are quite sensitive to heteroscedasticity correction schemes.     

Is there a Laffer curve between aggregate output and public sector employment?

This paper develops a model of the relationship between public sector employment, total output and aggregate real demand in market prices, where public employment has a positive productivity effect on private output. Public employment crowds out private employment and output because its increase induces higher wages and taxes. The valuation of government output is also taken into account. While public employment affects total output and aggregate real demand in an a priori ambiguous way, numerical simulations suggest that the relationship may be nonlinear; positive, when public sector is “small” and negative, when it is “large”. Using the annual data from 22 OECD countries over the period 1960–1996 and estimating and testing for threshold models and more commonly used specifications with multiplicative interaction terms give support to this nonlinearity hypothesis between public employment and private sector output. First version received: October 1996/Final version received: April 2000