Sudden changes in variance and time varying hedge ratios

This paper analyzes the influence of sudden changes in the unconditional volatility on the estimation and forecast of volatility and its impact on futures hedging strategies. We employ several multivariate GARCH models to estimate the optimal hedge ratios for the Spanish stock market including in each one some well-known patterns that may affect volatility forecasts (asymmetry and sudden changes). The main empirical results show that more complex models including sudden changes in volatility outperform the simpler models in hedging effectiveness both with in-sample and out-of-sample analysis. However, the evidence is stronger when the loss distribution tail is used as a measure for the effectiveness (Value at Risk (VaR) and Expected Shortfall (ES)) suggesting that traditional measures based on the variance of the hedged portfolio should be used with caution.     

基于便利收益的商品期货套期保值策略研究

依据便利收益是商品现货与期货长期均衡关系的主要影响因素,研究商品便利收益对商品期货套期保值策略的影响。通过求解最大化期望效用的套期保值决策模型,得到了最优套期保值比率的封闭解,并且提出了以便利收益为修正因子的ECT-GARCH模型,同时选取2005年01月到2013年10月期间沪铝现货和期货数据进行实证分析。研究发现:便利收益的波动性与套期保值比率呈负相关,在套期保值比率估计精度和套期保值绩效方面,ECT-GARCH模型均优于B-GARCH模型和ECM-GARCH模型。     

基于Copula-TGARCH模型的股指期货最佳套期保值比研究

本文基于一种新的Copula-TGARCH模型估计股指期货的最佳套期保值比,根据现货和期货收益率序列不同的尾部相依性,用不同的Copula函数形式(Gumbel,Clayton,Gaussian)拟合两者的相关性,并与其它的动态套期保值模型(ECM-CCC-GARCH和ECM-DVEC-GARCH)比较其套期保值的有效性。通过对香港恒生指数现货和期货的实证分析发现:无论样本期内、外,Copula-TGARCH模型的套期保值效果均优于其它模型,而基于非对称Gumbel Copula的套期保值比最佳。     

股指期货考虑套期保值成本时的套期保值比率研究

所谓股指期货,就是以某种股票指数为标的物的金融期货合约.它同时具有股票与期货的特性,是组合投资者规避系统风险的重要金融衍生工具.针对股指期货,在考虑套期保值成本的前提下,利用套利和CAPM模型给出最优套期保值比率的计算公式.这将在一定的程度上,提高了计算的准确性,并且减少计算的工作量.     

基于Copula函数的我国股指期货风险及套期保值实证研究

运用SJC-Copula-GJR模型,计算了持有沪深300股指期货多头和空头两种组合的VaR值和最优投资比例,模型的特点是能够准确地描述尾部相关关系,且其对尾部相关性的描述是非对称的,所得结论为投资者进行风险管理提供了可靠的依据.同时,通过构造加权的非线性相关系数来计算沪深300股指期货最优套期保值比率,解决了分布非正态、期货与现货非线性的问题,准确地度量了股指期货收益率序列的动态相依关系,实证研究表明基于Copula函数的套期保值有效性明显地优于传统模型.     

考虑结算风险的套期保值研究

期货市场的风险转移功能主要通过套期保值策略来实现,期货市场套期保值的关键问题是套期保值比率的确定。现有套期保值研究侧重于规避价格风险,忽略了期货市场另一个重要的风险因素-结算风险。本文通过建立考虑结算风险的期货套期保值决策模型,有效地平衡了套期保值过程中的价格风险与结算风险。具体特色一是将套保者的结算风险厌恶态度直接反映到套期比的计算中,体现了结算风险对套期保值决策的影响;二是在一定条件下,本模型的套期比趋近于最小方差套期比;三是利用ARMA时间序列方法预测期货与现货的价格走势,有效地反映了期货价格一阶平稳和季节性变化规律,使估计的套期比更加精确可靠。     

The role of index bonds in universal currency hedging

This study examines the demand for index bonds and their role in hedging risky asset returns against currency risks in a complete market where equity is not hedged against inflation risk. Avellaneda's uncertain volatility model with non-constant coefficients to describe equity price variation, forward price variation, index bond price variation and rate of inflation, together with Merton's intertemporal portfolio choice model, are utilized to enable an investor to choose an optimal portfolio consisting of equity, nominal bonds and index bonds when the rate of inflation is uncertain. A hedge ratio is universal if investors in different countries hedge against currency risk to the same extent. Three universal hedge ratios (UHRs) are defined with respect to the investor's total demand for index bonds, hedging risky asset returns (i.e. equity and nominal bonds) against currency risk, which are not held for hedging purposes. These UHRs are hedge positions in foreign index bond portfolios, stated as a fraction of the national market portfolio. At equilibrium all the three UHRs are comparable to Black's corrected equilibrium hedging ratio. The Cameron-Martin-Girsanov theorem is applied to show that the Radon-Nikodym derivative given under a P -martingale, the investor's exchange rate (product of the two currencies) is a martingale. Therefore the investors can agree on a common hedging strategy to trade exchange rate risk irrespective of investor nationality. This makes the choice of the measurement currency irrelevant and the hedge ratio universal without affecting their values.     

期货套期保值C VaR风险的敏感度分析

把条件风险价值应用于期货组合套期保值的风险管理,分析条件风险价值对期货部位的敏感性.在一般的概率分布下,分空头套期保值和多头套期保值两种情况,导出期货组合套期保值的条件风险价值关于套期比的一阶和二阶变化率,并研究其经济意义.投资者可以根据条件风险价值的敏感度增减期货头寸,把握好用于套期保值的期货量,帮助投资者管理套期保值风险.     

Hedging of the European option in discrete time under proportional transaction costs

In the paper hedging of the European option in a discrete time financial market with proportional transaction costs is studied. It is shown that for a certain class of options the set of portfolios which allow to hedge an option in a discrete time model with a bounded set of possible changes in a stock price is the same as the set of such portfolios, under assumption that the stock price evolution is given by a suitable CRR model.     

A multi-stage financial hedging approach for the procurement of manufacturing materials

This paper addresses the problem of mitigating procurement risk that arises from volatile commodity prices by proposing a hedging strategy within a multi-stage time frame. The proposed multi-stage hedging strategy requires a commodity futures position to be correctly initialised and rebalanced with adequate volumes of short/long positions, so as to reduce the volatility in the total procurement cost that would otherwise be generated by varying commodity spot prices. The novelty in the approach is the introduction of the rebalancing of commodity futures position at defined intermediate stages. To obtain an efficient or near optimal multi-stage hedging strategy, a discrete-time stochastic control model (DSCM) is developed. Numerical experiments and Monte Carlo simulation are used to show that the proposed multi-stage hedging strategy compares favourably with the minimal-variance hedge and the one-stage hedge. A close-form optimal solution is also presented for the case when procurement volume and price are independent.     

Static Hedging with Uncertain Quantity and Departure from the Cost-of-Carry Valuation

In this paper, we are concerned with the optimal hedge ratio under quantity risk as well as discrepancies between the futures market price and its theoretical valuation according to the cost- of-carry model. Assuming a geometric Brownian motion for forecasting process, we model mispricing as a specific noise corn poncnt in the dynamics of filturcs market prices, based on which the optimal hedging strategy is calculated. Finally, we illustrate optimal strategy and its properties by numerical examples.     

期权组合最优套期保值模型及实证研究

根据实际投资中投资者可以选择不同到期日、不同敲定价格的期权组合进行套期保值的现实,本文建立了二次效用函数下期权组合最优动态套期保值模型,证明了该模型最优解存在的唯一性,并在协方差矩阵可逆和不可逆两种情形下分别给出了期权最优头寸的显式表达式。在50ETF价格先升后降、先降后升、下降和上升四种情形下,对上证50ETF期权的多种期权组合套期保值问题进行实证分析。研究结果表明:不同到期日不同敲定价格的看跌期权组合具有较好的套期保值效果。本文的研究为选择期权组合进行套期保值和解决展期期权套期保值问题提供了借鉴。     

基于Copula-ECM-GARCH模型的农产品期货套期保值绩效研究

Copula函数具有可以准确刻画变量间的相依结构、精准描述金融时间序列"尖峰厚尾"分布特点的良好统计性质.针对传统计量模型在计算套期保值比率时存在的局限性,利用Copula函数描述变量的尾部相关性,并结合ECM-GARCH模型,对大豆、小麦、玉米三种国内农产品期货进行套期保值研究,分别计算最优的套期保值比率及其绩效,并...     

A Stochastic Programming Model for Currency Option Hedging

In this paper we use a stochastic programming approach to develop currency option hedging models which can address problems with multiple random factors in an imperfect market. The portfolios considered in our model are rebalanced at the end of each time period, and reinvestments are allowed during the hedging process. These sequential decisions (reinvestments) are based on the evolution of random parameters such as exchange rates, interest rates, etc. We also allow the inclusion of a variety of instruments in the hedging portfolio, including short term derivative securities, short term options, and futures. These instruments help generate strategies that provide good liquidity and low trade intensity. One of the important features of the model is that it incorporates constraints on sensitivity measures such as Delta and Gamma. By ensuring that these hedge parameters track a desired trajectory (e.g., the parameters of a target option), the new model provides investment strategies that are robust with respect to the perturbations measured by Delta and Gamma. In order to manage the explosion of scenarios due to multiple random factors, we incorporate sampling within a scenario aggregation algorithm. We illustrate that when compared with other myopic hedging methods in imperfect markets, the new stochastic programming model can provide better performance. Our examples also illustrate stochastic programming as a practical computational tool for realistic hedging problems.     

基于风险约束的套期保值模型及沪深300股指实证研究

提出利用风险价值VaR建立套期保值资产组合的风险约束.以套期保值资产组合收益最大为目标,以控制套期保值资产组合风险为约束,建立了基于风险约束的套期保值模型.该模型在有效控制风险的基础上,可以大幅提高套期保值资产组合的收益.对沪深300股指现货和期货的数据进行了实证分析,对比了现有研究的最小二乘((OLS)、向量自回归(VAR)、向量误差修正(VEC)三种模型以及本文建立的基于风险约束的期货套期保值模型.样本内检验结果表明,本模型比现有研究模型的收益有大幅提高,平均增加81.6%.同时并没有失去对风险的控制,与现有研究模型只有5.32%的差别.对于样本外检验,模型在控制风险和提高收益两个方面都要优于现有研究模型.模型比现有研究模型平均可提高收益21.4%,平均降低风险3.61%.     

Black-Scholes期权定价的风险(英文)

Black-Scholes期权定价的推导假定对冲是连续的以达到无风险. 但事实上, 股市收市后将不再有交易, 所以投资者不能连续的调整其投资组合, 故期权定价的风险是存在的. 本文讨论了这种不连续对冲带来的期权定价的风险, 并以美国股市的几种指标股为例, 给出其比率. 比率多在5%以上, 有的可以达到38%, 可见传统期权定价的风险不容小觑.     

基于债券久期的国债期货套期保值模型分析

使用久期的方法在中国国债期货市场上进行套期保值是否有效?使用久期的方法研究国债期货套期保值的效率问题在国外已经很多,然而这种方法是否适合于目前中国的国债市场,相关研究还不多见,还有待进一步的证实.为此借鉴国外相关理论,采用比较研究的方法,以国债期货上市后2013年9月到2014年5月初,国债现货和国债期货的数据为样本,以基于久期的最优套期保值比率模型为主,其他模型为辅,比较出最优套期保值效率.研究结果表明,基于久期的套期保值方法在目前中国的国债市场效果一般.     

基于ARMA-GARCH-SN模型的沪深300股指期货日内波动率研究与预测

运用五个交易日的股指期货高频数据(每秒两笔),本文主要研究了沪深300股指期货日内波动率特征并对日内波动率预测。研究发现高频股指期货日内收益率有明显的波动率聚集和条件异方差现象,但无尖峰厚尾现象,收益率序列分布符合有偏正态分布。因此,我们对时间序列建立了最优的ARMA-GARCH-SN模型,并对模型拟合充分性做了验证,拟合结果发现ARMA(1,2)-GARCH(1,1)-SN模型基本能够刻画股指期货高频日内波动特征,条件方差所受的冲击具有很强的持续性、日内波动也具有长记忆性,最后我们还利用自助法对高频股指期货日内波动率两步预测、利用滚动回归预测方法对样本做了样本内预测。预测结果表明,波动率预测结果能够较好地反映股指期货日内波动特征。     

Optimal crop planting schedules and financial hedging strategies under ENSO-based climate forecasts

This paper investigates the impact of ENSO-based climate forecasts on optimal planting schedules and financial yield-hedging strategies in a framework focused on downside risk. In our context, insurance and futures contracts are available to hedge against yield and price risks, respectively. Furthermore, we adopt the Conditional-Value-at-Risk (CVaR) measure to assess downside risk, and Gaussian copula to simulate scenarios of correlated non-normal random yields and prices. The resulting optimization problem is a mixed 0?C1 integer programming formulation that is solved efficiently through a two-step procedure, first through an equivalent linear form by disjunctive constraints, followed by decomposition into sub-problems identified by hedging strategies. With data for a representative cotton producer in the Southeastern United States, we conduct a study that considers a wide variety of optimal planting schedules and hedging strategies under alternative risk profiles for each of the three ENSO phases (Niña, Niño, and Neutral.) We find that the Neutral phase generates the highest expected profit with the lowest downside risk. In contrast, the Niña phase is associated with the lowest expected profit and the highest downside risk. Additionally, yield-hedging insurance strategies are found to vary significantly, depending critically on the ENSO phase and on the price bias of futures contracts.     

The natural hedge of a gas-fired power plant

Electricity industries worldwide have been restructured in order to introduce competition. As a result, decision makers are exposed to volatile electricity prices, which are positively correlated with those of natural gas in markets with price-setting gas-fired power plants. Consequently, gas-fired plants are said to enjoy a “natural hedge.” We explore the properties of such a built-in hedge for a gas-fired power plant via a stochastic programming approach, which enables characterisation of uncertainty in both electricity and gas prices in deriving optimal hedging and generation decisions. The producer engages in financial hedging by signing forward contracts at the beginning of the month while anticipating uncertainty in spot prices. Using UK energy price data from 2006 to 2011 and daily aggregated dispatch decisions of a typical gas-fired power plant, we find that such a producer does, in fact, enjoy a natural hedge, i.e., it is better off facing uncertain spot prices rather than locking in its generation cost. However, the natural hedge is not a perfect hedge, i.e., even modest risk aversion makes it optimal to use gas forwards partially. Furthermore, greater operational flexibility enhances this natural hedge as generation decisions provide a countervailing response to uncertainty. Conversely, higher energy-conversion efficiency reduces the natural hedge by decreasing the importance of natural gas price volatility and, thus, its correlation with the electricity price.