The evolution of stock market efficiency in the US: a non-Bayesian time-varying model approach

A non-Bayesian time-varying model is developed by introducing the concept of the degree of market efficiency that varies over time. This model may be seen as a reflection of the idea that continuous technological progress alters the trading environment over time. With new methodologies and a new measure of the degree of market efficiency, we examine whether the US stock market evolves over time. In particular, a time-varying autoregressive (TV-AR) model is employed. Our main findings are: (i) the US stock market has evolved over time and the degree of market efficiency has cyclical fluctuations with a considerably long periodicity, from 30 to 40 years; and (ii) the US stock market has been efficient with the exception of four times in our sample period: during the long recession of 1873–1879; the recession of 1902–1904; the New Deal era; and the recession of 1957–1958 and soon after it. It is then shown that our results are partly consistent with the view of behavioural finance.     

分形及其在证券市场上的应用

比较了有效市场假设与分形市场假设,也即比较了证券市场的线性与非线性的观点,同时还对沪深股指通过比较周收益率与日收益率的分布发现指数的分形特征。     

Fear connectedness among asset classes

This study investigates the interconnection between five implied volatility indices representative of different financial markets during the period 1 August 2008–29 December 2017. To this end, we first perform a static and dynamic analysis to measure the total volatility connectedness in the entire period (the system-wide approach) using a framework recently proposed by Diebold and Yilmaz. Second, we make use of a dynamic analysis to evaluate both the net directional connectedness for each market and all net pairwise directional connectedness. Our results suggest that a 38.99%, of the total variance of the forecast errors is explained by shocks across markets, indicating that the remainder 61.01% of the variation is due to idiosyncratic shocks. Furthermore, we find that volatility connectedness varies over time, with a surge during periods of increasing economic and financial instability. Finally, we also document frequently switch between a net volatility transmitter and a net volatility receiver role in the five markets under study.     

Asymmetry in forward exchange rate bias: A puzzling result

In this paper we document that the hypothesis that the forward exchange rate discount is an unbiased predictor of future currency depreciation holds in periods when the forward US dollar is quoted at a premium against the Japanese yen and the Deutschmark, but fails when it is quoted at a discount for the post-Bretton Woods floating exchange rate era. Moreover, the observed asymmetry is statistically significant. This puzzling result remains to be explained.     

短期国际资本流动对我国经济潜在冲击的实证分析

短期国际资本的流动会扰乱一国经济或金融市场的稳定。本文基于我国1997年1月—2009年9月的月度数据,根据赤池信息准则与施瓦茨信息准则,采用泊松相关系数,对VAR试算取得变量间或有影响机制,并根据测算结果对相关宏观经济指标做OLS回归分析。结果表明,短期国际资本的流动增大了中国证券市场的波动性,而对M2,CPI和ER等指标影响并不显著。本文最后根据结论对当前短期资本流动监管提出几点建议。     

Oil currencies in the face of oil shocks: what can be learned from time-varying specifications?

While the oil currency property is clearly established from a theoretical viewpoint, its existence is less clear-cut in the empirical literature. We investigate the reasons for this apparent puzzle by studying the time-varying nature of the relationship between real effective exchange rates of five oil exporters and the real price of oil in the aftermath of the oil price shocks of the last two decades. Accordingly, we rely on a time-varying parameter VAR specification, which allows the responses of real exchange rates to different oil price shocks to evolve over time. We find that the reason of the mixed results obtained in the empirical literature is that oil currencies follow different hybrid models in the sense that oil countries’ real exchange rates may be driven by one or several sources of oil price shocks that furthermore can vary over time. In addition to structural changes affecting oil countries, structural changes arising from the oil market itself through the various, time-varying sources of oil price shocks are found to be crucial.     

基于R/S分析的上海股市有效性实证研究

以上海股票市场为研究对象,以1995年10月24日至2009年3月16日这一时间段的上证综合指数日收盘价对数收益率序列为研究样本,利用R/S分析方法计算出上证指数的Hurst指数,并对上海股市分形特征加以描述。实证结果表明,上证综合指数日收益率序列的Hurst指数为0.619607,明显偏离0.5,说明上海股票市场具有明显的分形特征,投资者可以通过分析股价的历史数据来获得超额利润,因而市场是无效的。最后,分析了上海股市无效的原因,并提出了政策和建议。     

Is the efficient market hypothesis day-of-the-week dependent? Evidence from the banking sector

In this article, we propose a new hypothesis: that the efficient market hypothesis is day-of-the-week-dependent. We apply the test to firms belonging to the banking sector and listed on the NYSE. We find significant evidence that the efficient market hypothesis is day-of-the-week-dependent. Overall, for only 62% of firms, the unit root null hypothesis is rejected on all the five trading days. We also discover that when investors do not account for unit root properties in devising trading strategies, they obtain spurious profits.     

我国货币政策对股票市场影响的实证研究

对货币政策与股票市场关系的文献进行了回顾,然后运用2009～2012年的时间序列数据,实证研究货币供应量和利率对股票价格的影响,结果表明：我国的货币政策对股票市场存在影响,而货币供应量的增加会使股价上涨,利率的上升会使股价下跌。根据实证结果,提出相应的对策建议。     

Nonlinearity in Stock Exchange Markets: The Case of Bist 100 Indices

In this paper,using data for the Bist 100 index,we investigate the presence of nonlinearities by employing several nonlinearity tests.The Brock,Dechert,and Sche...     

FDI、对外贸易对区域经济增长的影响——以湖南省为例

本文利用湖南省1985～2006年经济数据,根据协整理论和VAR模型等方法,从不同角度研究了FDI、对外贸易和经济增长之间的动态关系。实证结果表明,FDI、对外贸易与经济增长间具有长期均衡关系,且湖南省地区生产总值的增长与FDI和进口额都有双向因果关系;经济增长对进出口的波动冲击都表现出正向响应,而FDI由于地区因素的影响,作用较小。     

Testing for weak-form efficiency of crude palm oil spot and future markets: new evidence from a GARCH unit root test with multiple structural breaks

There is a sizeable literature that tests for weak-form efficiency in commodity and energy spot and future prices. While many studies now allow for multiple structural breaks to address the criticism that conventional unit root tests have low power to reject the unit root null in the presence of structural change, the extant literature overlooks the fact that conventional unit root tests are biased in the presence of conditional heteroscedasticity. We apply a recently developed generalized autoregressive conditional heteroscedasticity (GARCH) unit root test with multiple structural breaks to crude palm oil spot and future prices and find much more evidence against weak-form efficiency than that found using tests that fail to allow for conditional heteroscedasticity. Our results point to the importance of allowing for heteroscedasticity when testing for efficiency in commodity and energy spot and future prices.     

中国沪深股市的自组织临界性——基于沙堆模型的分析

利用沙堆模型,探讨了中国沪深股市的内在动力学机制,对沪深两市上涨和下跌过程中股价波动量和波动持续时间进行了统计分析。结果显示:股价波动量和波动持续时间的分布服从幂次定律,具有时空尺度下的无标度性,从而证明了股市存在分形结构。分形结构的存在表明,各股市投资者之间具有长程相关性,股价具有长期记忆性。由于投资者的风险偏好不同,因此股市的上涨与下跌性质具有差异性,损失的耗散速度比收益要快。     

人民币与欧元、美元、日元之间的汇率联动分析

利用向量自回归模型和多变量GARCH模型,对人民币汇率改革以来人民币、欧元、美元和日元之间的收益溢出效应和波动溢出效应进行了研究。结果显示欧元、美元和日元对人民币存在显著的收益溢出效应和波动溢出效应,但是人民币对其他几种货币的收益溢出效应和波动溢出效应并不显著。研究结果表明,人民币汇率形成机制改革以来,人民币汇率正在融入世界主要货币汇率市场,但是人民币汇率市场尚不成熟,目前我国仍然应该实行有管理的浮动汇率制度。     

保险产业市场结构和市场绩效的关系研究

对于市场结构和市场绩效的关系问题,理论界存在两个较为权威的假说,即市场力量假说和效率结构假说。笔者通过实证分析检验这两个假说在我国保险市场中的适用性,认为在我国保险市场存在传统的市场结构—市场行为—市场绩效假说,保险市场可以通过增加有效率企业的数量,引入竞争机制,最终通过市场自然选择的过程,形成少数新的规模大并能够具有市场力量的保险公司,从而提高保险业的绩效水平。