A Note on adding-up restrictions when modelling trade flows

An ad hoc rule is often required when modelling trade in multi-country models to ensure that aggregate imports equal aggregate exports in volumes and values. This paper offers an approach that offers some advantages over current methods.     

人民币兑美元汇率的风险测量

风险价值 (VaR)是一种计算金融市场风险的综合方法。基于ARCH模型的方差—协方差法计算VaR的基本原则 ,选取人民币 /美元的每日汇率为研究对象 ,测度了人民币兑美元汇率的风险轨迹。     

小麦期货市场价格波动与到期效应的实证研究

通过对小麦期货市场期货品种收益率的分布与波动性进行实证分析,论证其时间序列存在ARCH效应;运用ARMA-GARCH模型对小麦期货品种进行了拟合分析和统计检验,结果表明小麦期货品种的波动性具有很高的持续性。通过添加到期时间的哑变量,可以证明大多数小麦期货合约存在到期效应。     

政府主导还是市场主导--我国转轨金融运行机制的评价研究

转轨过程中,我国金融运行机制是采取政府主导还是市场主导模式是经济学界争论的焦点,文章应用ARCH类模型对我国金融运行机制进行实证研究,结果表明我国金融运行机制与西方市场经济国家存在显著区别。在我国转轨的特定阶段,金融系统无法依靠自身的力量达到稳定状态,只有靠外部力量的非市场干预才能实现金融系统的平稳运行。目前在金融系统自身不具备自我稳定的功能条件下,政府的外部干预是金融系统平稳运行的前提,否则会导致金融系统陷入剧烈的波动之中。     

Generalized runs tests to detect randomness in hedge funds returns

The major contribution of this paper is to make use of generalized runs tests (Cho and White, 2011) to analyze the randomness, i.e. the lack of persistence, in both absolute and relative returns of hedge funds. We find that about 42% of the HFR universe exhibit iid absolute returns over the period spanning 2000 to 2012. These funds are mainly found in proportions within the Macro and Equity Hedge strategies. A similar result holds for relative returns. We also find that funds having non-iid returns often exhibit ARCH effects and structural breaks, with largest breaks located within financial crises. Also, only a small percentage displays persistence in their relative performance, 8.2% to 16.7% of the universe, mainly found in proportions within the Relative Value and Event-Driven strategies. The robustness of results is challenged by implementing the tests on a crisis-free period. We find similar results for absolute returns. For relative ones, differences appear across strategies and benchmarks, but still both ARCH and breaks are present. Our work contributes to the hedge fund literature in terms of methodology, portfolio allocation, and performance measurement.     

A robust VaR model under different time periods and weighting schemes

This paper analyses several volatility models by examining their ability to forecast Value-at-Risk (VaR) for two different time periods and two capitalization weighting schemes. Specifically, VaR is calculated for large and small capitalization stocks, based on Dow Jones (DJ) Euro Stoxx indices and is modeled for long and short trading positions by using non parametric, semi parametric and parametric methods. In order to choose one model among the various forecasting methods, a two-stage backtesting procedure is implemented. In the first stage the unconditional coverage test is used to examine the statistical accuracy of the models. In the second stage a loss function is applied to investigate whether the differences between the models, that calculated accurately the VaR, are statistically significant. Under this framework, the combination of a parametric model with the historical simulation produced robust results across the sample periods, market capitalization schemes, trading positions and confidence levels and therefore there is a risk measure that is reliable.

居民消费价格指数ARCH族模型检验

居民消费价格指数(CPI)在一定程度上反映了通货膨胀或紧缩程度,往往成为各种研究关注的重点。应用GARCH类模型对月度CPI的波动性进行了建模.结果表明该模型能有效拟合月度CPI的波动性特征;并根据分析得出我国市场经济还不成熟。     

中国股票市场收益和波动溢出效应实证分析

运用Granger因果检验模型和ARCH类型模型对沪深股市收益之间的关联性和波动溢出效应进行实证分析,这对于研究股市的结构和判断股市的走势及风险传递无疑具有重要的作用。结论显示:沪深股市日收益间有很强的相关性,沪市日收益的历史信息能用来改善对深市未来趋势的预测;沪深股市间存在显著的双向波动“溢出效应”。     

Heterogeneity effects from market interventions

The aim of this paper is to test whether the European Commission activities generate a heterogeneity effect on the merging parties. A sample of 74 firms involved in 45 contested merger and acquisition operations during the years 1990 to 1999 is used. The methodology is based on the GARCH framework. The main result is that, globally, the DGC interventions seem not to reduce significantly the heterogeneity among investors, except for the operations where it takes strong decisions like prohibition. In these last cases, the signal coming from the DGC encompasses valuable information and is well understood by market participants.