价值型投资在中国证券市场上的有力证据

本文给出了1994年至2005年间价值型投资在中国A股市场中的有力证据。Fama—MacBeth回归表明在中国A股市场中存在着显著的市盈率和市净率溢价，1994年至2005年中牛市和熊市的滚动策略显示了我国A股市场中的价值效应，并且风险和收益之间基本上呈现出收益大、风险大的特征。本文的实证研究结果将有助于中小投资者以及机构投资者的长期投资决策。     

试论现阶段电子商务的交易安全技术

随着信息技术日新月异的发展，人类正在进入以网络为主的信息时代，基于Intemet开展的电子商务已逐渐成为人们进行商务活动的新模式。但电子商务的安全问题变得越来越突出，建立一个安全、便捷的电子商务应用环境，关键在于保证整个商务活动中信息的安全性，使基于Intemet的电子交易方式与传统交易方式一样安全可靠。电子商务安全包括计算机网络安全和商务交易安全。商务交易安全主要是通过加密技术、安全机制、安全协议进行保证的。     

电子商务时代柠檬问题的出现及解决

电子商务时代质量的不确定性引起了柠檬问题的出现,而柠檬问题会导致产品和服务质量降低的不对称信息趋势,所以解决这个问题的方法就是要把相关信息告知消费者,让消费者对产品的质量有把握。本文针对电子商务时代的柠檬问题给出了四个解决方案,并重点讨论了利用中介的解决方案,分析了中介在电子商务中的重要作用和中介改变电子商务市场效率的问题。     

我国合理市盈率与股市泡沫的实证分析

市盈率是被广泛用来测量股市泡沫风险的一个重要指标。本根据“股票的理论价格应该是未来各期红利的贴现之和”这一传统金融理论，导出用以衡量股市泡沫成分的基准——合理市盈率的计算方法。通过分析发现市盈率的合理值是一个动态值，据此测量出的上海A股市场泡沫成分自1993年以来呈明显下降趋势，说明我国股票市场上的投资日趋成熟，投资行为日趋理性。     

Investment-specific shocks and external balances in a small open economy model

Abstract.  We set up a standard small open economy business cycle model driven by government spending shocks, neutral productivity (TFP) shocks, and investment-specific shocks. The model is calibrated to quarterly Canadian data and its predicted moments and sample paths are compared with their Canadian counterparts. We find that the model captures the dynamics in investment and in the trade balance better than special cases of the model where either one of the productivity shocks is omitted. More specifically, the model matches the variance of the trade balance-output ratio, its correlation with output and its autocorrelation. It also matches the output-investment correlation.     

Convergence in West German Regional Unemployment Rates

Abstract. Differences in regional unemployment rates are often used to describe regional economic inequality. This paper asks whether changes in regional unemployment differences in West Germany are persistent over time. Understanding the persistency of regional unemployment differences helps us to assess how effective regional policy can be. While univariate tests suggest that changes in regional unemployment differences are persistent in West Germany, more powerful panel tests lend some support to the hypothesis that regional unemployment rates converge. However, these tests reveal a moderate speed of convergence at best. Because there is a structural break following the second oil crisis, we also use tests that allow for such a break. This provides evidence for both convergence and quick adjustment to an equilibrium distribution of regional unemployment rates that is, however, subject to a structural break.     

Income distribution, borrowing constraints and redistributive policies

This paper sheds light on the relationship between income inequality and redistributive policies and provides possible guidance in the specification of empirical tests of such a relationship. We model a two-period economy where capital markets are imperfect and agents vote over the level of taxation to finance redistributive policies that enhance future productivity. In this context, we show that the pivotal voter is not necessarily the agent (class) with median income. In particular, the poor, who are more likely to be liquidity constrained, may form a coalition with the rich and vote for low redistribution. The effects of an increase in income inequality on the level of redistribution turn out to depend on whether the increase in inequality is concentrated among the poor or the middle class. Empirical results from a panel of 22 OECD countries provide preliminary evidence consistent with our main theoretical implications.     

Revisiting the case for a populist central banker

It is known that discretionary policy may give rise to an inflationary bias if wages are negotiated in nominal terms. In a recent issue of this Review, Guzzo and Velasco argued that this bias can be eliminated, and welfare maximized, by the appointment of a central banker who does not care at all about inflation (a ‘populist’ central banker). A conceptual flaw of the latter result is identified here. It is shown that when wages are negotiated in nominal terms the result is true only in the special case of a single, all-encompassing, union. In the more general case of multiple unions, however, inflation increases linearly with their number and a populist central bank may turn out to decrease welfare.     

Inflation, investment and economic performance: The role of internal financing

This paper studies a link between inflation and economic activity that is built on two hypotheses. First, firms mitigate informational frictions in financial markets by accumulating retained earnings over a period of time. Second, firms allocate earnings among three competing uses - dividends, current investment, and the accumulation of internal funds - and inflation directly distorts this allocation decision as well as the real value of accumulated internal funds. The model predicts that the level of inflation - both unanticipated and expected inflation - as well as the variability of inflation distort firms’ internal financing decisions, increases frictions in financial markets, reduces the level and efficiency of investment, and reduces aggregate output. The marginal effects of inflation are increasing in the inflation rate.     

Collateral constraints and the amplification mechanism

Kiyotaki and Moore (J. Polit. Economy 105 (1997) 211) have offered a theory for how common shocks to credit-constrained firms are amplified through changes in collateral values and transmitted as fluctuations in output. I clarify and extend their model by showing that their collateral amplification mechanism is not robust to the introduction of markets that allow these firms to hedge against common shocks. A theory of incomplete hedging is proposed in which the supply of hedging available in the economy is constrained by the aggregate value of collateral. I illustrate how the constraint reinstates amplification effects and discuss empirical implications of this new mechanism.