基于SWARCH的VaR及压力测试值的一致性估计

风险值 (VaR) 与压力测试都是衡量金融资产价格波动风险的重要工具.为了考虑市场在不同状态下报酬率分布的结构性变化,引入波动性状态转移的ARCH(SWARCH)模型对波动性进行描述,使 VaR 与压力测试值能够在统一的样本数据和框架下得到一致性的估计.此外,SWARCH模型还同时考虑了金融市场波动性、波动性状态和状态概率的时变性,使 VaR 与压力测试值的估计具有很好的灵活性.以上海股市为样本进行了实证分析,验证了基于SWARCH模型能够得到 VaR 与压力测试值的一致性估计.     

基于VaR的我国商品期货市场风险的预警研究

本文以郑州商品交易所的硬麦期货和上海期货交易所的铜期货为例,构造了期货合约收益率连续时间序列,计算了序列的VaR值,对预测结果的有效性进行了检验,并提出了将VaR曲线和保证金水平相结合的方法,对商品期货市场风险进行单指标预警.     

同种商品不同月份期货组合风险评价模型研究及应用

以期货合约的每一交易日的对数涨跌率来反映市场风险,借助VaR风险价值法,运用加权核估计技术(WKDE)和指数加权滑动模型(EWMA),建立了基于期货组合中持有头寸不同且可以进行风险对冲的期货组合市场风险非线性叠加评价模型,解决了同种商品、不同月份期货组合每一交易日最大损失的确定问题,并通过实证研究验证了模型的实用性.该模型的特点一是借助WKDE法预测组合中单个合约每一交易日涨跌率最大日亏损值,充分体现了期货合约涨跌率的实际走势,使VaR估计更加精确.二是通过动态迁移相关系数矩阵的计算保证了模型的精确性.采用EWMA模型预测动态变化的方差-协方差矩阵,从实证的角度得到更精准的动态迁移相关系数矩阵.三是考虑了组合中多头和空头不同头寸之间的风险对冲,避免了实际中期货组合风险的线性相加而造成放大风险或减少风险的不准确性,从而能较好地保证了模型的预测精度及准确性.四是通过基于风险非线性叠加建立的期货组合风险评价模型解决了SPAN系统中期货组合风险的线性叠加问题,从而得到更合理的组合风险预测值.     

股指期货套利交易的风险度量——基于沪深300股指期货交易数据的实证分析

以Copula理论和VaR方法作为实证分析工具,根据我国股指期货市场的实际交易情况,对套利投资组合的风险进行量化分析。根据我国股指期货市场的实际交易情况,针对套利交易中的期现套利、跨期套利、跨市场套利和跨品种套利这四种基本交易策略展开全面分析,并基于实证得到的投资组合VaR值,衡量了在不同策略下套利投资组合的风险。同时,将其与基于二元正态分布和样本数据得到的VaR值进行比较。这填补了我国在股指期货套利组合风险度量方面的空白,具有重要的理论价值和现实意义,对我国当前的股指期货套利交易的风险管理起到了一定程度的补充和启示作用。     

嵌入战略因子的VaR模型改进研究

传统VaR模型是一种衡量短期投资风险的常用工具,但其衡量长期风险的有效性仍然有所欠缺。并且,传统VaR方法基于历史数据对未来风险进行估算的基础性假定已引起诸多学者的质疑。据此本文提出基于战略考虑的VaR模型改进问题。首先提出战略因子这一综合评价企业战略的概念,然后利用德尔菲法和模糊层次分析法求出其具体表达式,最后基于实证数据的拟合将其嵌入到原有VaR模型中,得到改进后的战略在险值(Strategic Value-at-Risk, SVaR)模型。实证检验的结果表明,改进后得到的SVaR模型预测的长期风险值要比原VaR模型更加准确。     

供应链融资业务中钢材质押贷款动态质押率设定的VaR方法

异于债券、股票等质押融资业务,存货质押业务动态质押的核心在于预测其长期价格风险。从分析存货质押市场收益率的统计特征出发,以场外现货交易为主的钢材((HRB335)日数据为例,建立能刻画钢材收益率序列异方差性和尖峰厚尾特性的VaR-GARCH(1,1)-GED模型。同时,提出置于多风险窗口下运用样本外预测未来质押期内钢材价格风险水平,给出厚尾分布下长期风险VaR的计算解析式,得出与银行风险承受能力相一致的质押率。进而,基于失效率法则建立长期风险的碰撞序列函数,回测多风险窗口下长期VaR值。实证分析显示,模型得到的质押率在控制好风险的同时降低了效率损失,为商业银行提供一种动态质押率的风险管理模式和框架。     

加权复合分位数回归方法在动态VaR风险度量中的应用

风险价值(VaR)因为简单直观,成为了当今国际上最主流的风险度量方法之一,而基于时间序列自回归(AR)模型来计算无条件风险度量值在实业界有广泛应用。本文基于分位数回归理论对AR模型提出了一个估计方法--加权复合分位数回归(WCQR)估计,该方法可以充分利用多个分位数信息提高参数估计的效率,并且对于不同的分位数回归赋予不同的权重,使得估计更加有效,文中给出了该估计的渐近正态性质。有限样本的数值模拟表明,当残差服从非正态分布时,WCQR估计的的统计性质接近于极大似然估计,而该估计是不需要知道残差分布的,因此,所提出的WCQR估计更加具有竞争力。此方法在预测资产收益的VaR动态风险时有较好的应用,我们将所提出的理论分析了我国九只封闭式基金,实证分析发现,结合WCQR方法求得的VaR风险与用非参数方法求得的VaR风险非常接近,而结合WCQR方法可以计算动态的VaR风险值和预测资产收益的VaR风险值。     

VaR方法及其在股市风险分析中的应用初探

本文讨论了度量投资风险的VaR方法的概念和计算方法,在股票价格随机游动的假设下计算了深圳股市在不同置信水平下的风险值,并与实际投资收益做了对比。在算例分析的基础上,对VaR方法在我国股票投资中的应用进行了初步探讨。     

基于信号传递模型的风险资本退出的并购定价分析

运用信号传递模型分析了风险投资企业并购的分离均衡和混同均衡及其不同风险资本家类型条件下的并购均衡价格.分析结果表明,风险资本家的预期收益与信号传递成本、其他投资者对风险资本真实价值的判断及其获得并购收益后的后验概率,是影响风险资本并购博弈均衡价格的主要因素,完善风险企业的信息披露制度对解决风险资本退出中的逆向选择问题至关重要.我国两个不同类型的典型案例分析有力地支持了博弈分析结果.     

可违约零息债券风险综合度量Monte Carlo方法

可违约零息债券同时面临着违约风险和市场风险(利率风险)这两类主要风险.相对于传统的不同类风险独立度量方法,也不同于割裂两类风险再进行加总或通过Copula函数关联,本文在信用风险强度定价模型的基础上,同时考虑信用风险、市场风险和两类风险之间的相关关系,建立了计算可违约零息债券综合风险VaR的Monte Carlo方法,得出同一个风险计算期下反映两类风险的损失分布和同一个某置信度的损失分布的分位点,进而能求得风险综合VaR值,这样可在同一个框架下同时捕捉可违约零息债券的两类风险,这里,给出了MonteCarlo模拟方法具体技术细节,包括违约时间和基础状态向量过程的模拟.最后运用本文的风险综合度量模型对短期融资券的综合风险进行计算,得出风险综合VaR值,并与利率风险独立度量VaR值和信用风险独立度量VaR值进行比较分析.     

Board attributes and shareholder wealth in mergers and acquisitions: a survey of the literature

The question of whether a “good” corporate board structure can optimize performance and minimize conflicts between managers and shareholders has been widely debated. Because mergers and acquisitions represent major managerial investment decisions that are subject to board scrutiny, the effectiveness of a board’s structure is especially visible in the context of corporate acquisitions. With that in mind, in this paper, we examine the abundant literature in the fields of strategic management, economics, and finance in order to identify which board attributes contribute to the ability of corporate boards to create value through mergers and acquisitions. In particular, we discuss the impact of four board attributes: (1) board independence, (2) board size and director-specific attributes, (3) board ownership and compensation, (4) multiple directorships. As a result of our analysis, we conclude that the impact of board attributes on shareholder wealth in mergers and acquisitions is specific to each firm. Therefore, board regulations that do not reflect a firm’s specific needs may in fact hinder the creation of a board that is capable of responding effectively to the firm’s unique needs and circumstances.     

The effect of mergers and acquisitions on productivity: An empirical application to Spanish banking

Mergers and acquisitions are frequently justified in terms of value creation or efficiency improvements. Nevertheless, the evidence is not consistent with the existence of benefits in terms of the costs, productivity, profitability or market value of the firms involved. A distinguishing feature of extant research is that it focuses on the assessment of the consequences of mergers around the time in which the operation takes place, limiting the possibility of observing a complete integration between the merged firms. In this context, the objective of this paper is to evaluate the effects of mergers and acquisitions on the long-run productivity of Spanish savings banks. Our results show that productivity improvements can be found in only half of the mergers that take place during the period analyzed.     

A financial survey of mergers during the years 1968–70

This paper is concerned with the financial objectives of mergers and acquisitions and the way in which considerations in the merger transaction, such as the price paid and the method of payment used, may affect such objectives subsequent to the merger. The analysis is based on a sample of 65 mergers during the years 1968–70 inclusive [2].     

The effect of board size on shareholder value: Evidence from bank mergers and acquisitions

This study examines the effect of board size on the economic impact of bank mergers and acquisitions (M&A) in the US. Using a hand-collected dataset of 508 M&A between 2012 and 2018, we find that board size is negatively related to acquirer excess returns. In an additional analysis, we show that large boards have positive value implications for banks that combine the CEO and chairman roles as well as for large banks. Our findings indicate that a “one-size-fits-all” approach to board size is not necessarily in the interests of shareholders; instead, a more flexible and proactive formulation is needed.     

Service diversification and growth of professional service firms

This study investigates the impact of service diversification on the rate and mode of firm growth in professional service firms (PSFs). Drawing on the extant PSF literature, we identify differing views regarding the growth impact of service diversification. Specifically, some scholars suggest that the external client benefits associated with service diversification should allow PSFs to expand revenues at a rapid pace and pursue less merger and acquisition activity, whereas others imply that increased diversification can cause internal challenges with respect to learning costs, coordination and innovation that can limit the rate of revenue growth and encourage more mergers and acquisitions. We test these competing views using longitudinal data on 137 accounting firms and cross-sectional data on 125 law firms and find that service diversification is negatively associated with the rate of firm revenue growth and positively associated with the use of mergers and acquisitions.     

Allocation Processes in Mergers and Acquisitions: An Organizational Justice Perspective

This paper contributes to the understanding of allocation processes in mergers and acquisitions by applying an organizational justice perspective. This is a perspective that has been neglected in past research on mergers and acquisitions, but which is important in understanding the challenges managers face in allocating human resources and other resources of symbolic importance. In particular, the paper examines the trade-offs between multiple goals in selecting distributive and procedural justice rules, and identifies factors that constrain these choices. Mergers and acquisitions are typically driven by multiple motives. The findings presented in this paper suggest that there are different approaches to applying justice rules in mergers and acquisitions and that these approaches have different implications for meeting multiple goals. The choice of equity in combinations with fair procedural rules is an approach which complies with the two goals of maximizing economic productivity and fostering relationships. However, the choice of this approach rests upon an unbalanced power relationship and relatively low ambiguity. When there is a high degree of ambiguity and a balanced power relationship, management has to make trade-offs between maximizing economic productivity and fostering relationships.     

我国上市公司并购中控制权变更市场效应的实证研究

针对1997年到2001年我国上市公司并购中控制权变更的282例样本,就其控制权变更公告日效应的平均超常收益率和累计平均超常收益率进行了实证分析。研究结论显示:我国上市公司并购中控制权变更的信号传递效应在[-2,2]区间上完全实现。在我国上市公司并购中控制权变更公告日收益率变动呈现出如下趋势:在公告日信号传递效应区间,其收益率显著为正;随着传递时间延伸,收益率显著为负,从而在整体上,我国上市公司并购中控制权变更对并购公司股东并未显示出明显绩效改善。上述结论统计检验极其显著的。     

Corporate raiders don't cut investment in R & D

A focal point of the public debate over the effects of corporate mergers and acquisitions is their impact on the level of spending on long term projects. This study examines the pre-and post-merger levels of spending on R & D and the more general category of capital expenditures. Analysis of expenditures for a sample of firms drawn from the largest corporate mergers in the US during the late 1970s indicate that long term spending rises significantly in the post-merger environment. This supports the view that acquiring firms. whether hostile or friendly, recognize the relationship between such spending and firm value.     

Planning acquisitions and mergers

This article considers the problems and opportunities associated with acquisitions and mergers. The author argues that despite the low level of activity in this area at the present time, growth oriented companies should be considering their related long-term objectives. An appropriate acquisition may successfully project a company on a growth path which it could not hope to achieve by organic growth alone. On the other hand ill-conceived acquisitions may just as speedily drive a company to disaster. The failure rate in acquisitions can be reduced by a planned approach. This article aims to explore the steps which a company ought to take from the time it decides to expand by acquisition to the time when the acquisition is integrated into the film.     

我国海外石油开发利用的国家风险评估

在对我国海外石油开发利用国家风险因素进行分析的基础上,运用模糊综合评判法构建海外石油开发利用风险评估模型,并基于层次分析法对相关风险指标体系进行权重确定;同时,选取了我国海外石油开发利用涉及的一些典型地区或国家进行石油开发利用风险评估。研究发现:政治风险是影响海外石油开发利用的非常重要风险因素;我国在中东地区进行石油开发利用的风险最大,其次是西非、北非以及俄罗斯地区。