Financial Sector Risk and the Stock Returns: Evidence from Tokyo Stock Exchange Firms

We investigate whether the activity of financial firms creates value and/or risk to the economy within the asset pricing framework. We use stock return data from nonfinancial firms listed in the first section of the Tokyo Stock Exchange. The value-weighted index that is solely composed of nonfinancial firms is augmented with the index of the firms from the financial sector, and we estimate multivariate asset pricing model with these two indices. We note that our procedure can simultaneously take into account the cross-holding phenomena among Japanese firms, especially between the financial sector and the nonfinancial sector. Our augmented index model performs well both with cross-sectional Fama and MacBeth regression test and GMM test. Our two index model with additional Fama and French's HML factor can capture cross-sectional variations of the returns of sample portfolios better than the original Fama and French model can, when measured by Hansen and Jagannathan distance measure. We find that this additional new sector variable can be a substitute for Fama and French's size factor, but not related to the bond index return. This variable has similar factor characteristic as money supply growth or the term structure, but the latter variables contain more information than the former. Morever, our financial sector model helps explain the return and risk structure of Japanese firms during the so-called bubble period.     

创业企业贷款组合风险管理研究——基于不同生命阶段的视角

投资品种的多样化与分散化是金融风险管理的核心方法,它可以有效地防范和控制各类风险。对银行业来说,将贷款分散地投放给不同行业、不同区域或处于不同生命阶段的企业,可以减少其因借款企业违约而可能遭受的损失。因此,银行在贷款投放过程中,如何进行多样化和分散化,以达到整个贷款组合收益的最大化和风险的最小化是一个决策难题。本文通过对贷款组合风险和预期收益的度量,提出针对不同生命阶段创业企业的贷款组合优化模型,并进行了相关实证研究,研究结果表明模型具有较强的适用性。     

Asymptotic analysis for optimal investment and consumption with transaction costs

We consider an agent who invests in a stock and a money market and consumes in order to maximize the utility of consumption over an infinite planning horizon in the presence of a proportional transaction cost . The utility function is of the form U(c) = c^1-p/(1-p) for p > 0, . We provide a heuristic and a rigorous derivation of the asymptotic expansion of the value function in powers of , and we also obtain asymptotic results on the boundary of the no-trade region.Received: July 2003, Mathematics Subject Classification (1991): 90A09, 60H30, 60G44JEL Classification: G13Work supported by the National Science Foundation under grants DMS-0103814 and DMS-0139911.     

Optimal Self-Reporting Schemes with Multiple Stages and Option Values

We consider a model of optimal law enforcement where sanctions can be reduced for self-reporting individuals. We distinguish between a first self-reporting stage before the case is investigated and a second one where the criminal is detected, but not yet convicted. Since we assume that violators have private information in both stages, fine reductions for self-reporting individuals lead ceteris paribus to a higher violation frequency. Nevertheless, we show that fine reductions should be granted in both stages. We characterize the connection between the two fine reductions in the optimal policy and relate our results to self-reporting schemes observed in reality.     

基于技术形成机理的自主创新决策模型研究

技术的形成是企业在特定时期将最新的创新思想和前沿知识相结合,并实现产业化的过程,它受到企业内部和外部多种因素的影响和制约。根据技术的形成机理,技术自主创新包括知识技术化、技术产品化和产品市场化等三个决策维度,并在每个决策维度运用相应的寻优原则进行评价与选择,形成了知识技术化决策模式、技术产品化决策模式和产品市场化决策模式,从而构建基于技术形成机理的企业技术自主创新的决策模型。     

EXPLICIT SOLUTIONS OF CONSUMPTION-INVESTMENT PROBLEMS IN FINANCIAL MARKETS WITH REGIME SWITCHING

We consider a consumption and investment problem where the market presents different regimes. An investor taking decisions continuously in time selects a consumption–investment policy to maximize his expected total discounted utility of consumption. The market coefficients and the investor's utility of consumption are dependent on the regime of the financial market, which is modeled by an observable finite-state continuous-time Markov chain. We obtain explicit optimal consumption and investment policies for specific HARA utility functions. We show that the optimal policy depends on the regime. We also make an economic analysis of the solutions, and show that for every investor the optimal proportion to allocate in the risky asset is greater in a bull market than in a bear market. This behavior is not affected by the investor's risk preferences. On the other hand, the optimal consumption to wealth ratio depends not only on the regime, but also on the investor's risk tolerance: high risk-averse investors will consume relatively more in a bull market than in a bear market, and the opposite is true for low risk-averse investors.     

Optimal Income Taxation and the Ability Distribution: Implications for Migration Equilibria

As recently argued by Diamond (1998), one of the key factors explaining the progressivity of an optimal non-linear income tax is the distribution of productivity among workers. Migration is one source of changes in the productivity distribution. How changes in the populations ability distribution affect optimal income tax schedules has received little attention. Changing the distribution generally affects both the objective function and the government budget constraint. We first consider the comparative statics of the fraction of highly-skilled workers with maximin and maximax welfare functions (so that only the second effect is present) and a quasi-linear utility function. We also present some results for a utilitarian social welfare function.We then study the interaction between mobility and redistributive taxation. We consider mobility by either the skilled or unskilled population under majority voting where governments take the population as fixed. If individuals choose to relocate independently, having identical ability distributions is always a stable equilibrium when the unskilled are the mobile group. However, this is not always the case when the skilled are mobile. If groups of individuals can choose where to locate, having identical ability distributions across regions is only an equilibrium when the mobile type has an overall majority.     

银行最优资本结构问题分析

本文在一个两时期模型中分别分析了无资本监管和实行资本监管时银行最优资本结构的选择。在这两种情况下,银行都可以选择一个最优资本结构以实现其价值最大化。在无资本监管时,当边际收益等于边际成本时,银行的资本结构达到最优;在实行资本监管的情况下,银行的最优资本数量是无监管时的最优资本数量再加上一个缓冲资本。     

Equity premium prediction and optimal portfolio decision with Bagging

We propose using the statistical method of Bagging to forecast the equity premium out-of-sample for multivariate regression models. Bagging allows for the flexible and efficient extraction of valuable informational content from a large set of predictors, leading to statistically and economically significant gains relative to not only the historical mean, but also other soft-threshold methods such as forecast combinations and shrinkage estimators in our empirical results. Furthermore, we find that the source of economic gains for Bagging primarily comes from the fact that it encourages the investor to actively manage portfolio by flexibly utilizing short selling or leveraging to better time the market following correctly prognosticated trends. However, other strategies such as forecast combinations keep the equity shares nearly fixed regardless of the predicted market prospect.