产业链视角下乳制品价格溢出效应研究——基于VAR-BEKK-GARCH(1,1)模型

奶业产业链是乳制品价格形成的基础,从产业链着手有助于发现乳制品价格溢出效应的本质特征。本文选取牛奶、酸奶、婴幼儿奶粉、老年奶粉作为乳制品的代表,基于2010年5月至2018年5月乳制品产业链月度价格数据,使用VAR-BEKK-GARCH(1,1)模型分析乳制品产业链各环节间的价格溢出效应。研究发现:婴幼儿奶粉产业链上、中、下游价格间存在显著的单向均值溢出效应,而牛奶、酸奶、老年奶粉产业链的中游对上游、下游对中游价格存在显著的单向均值溢出效应;牛奶、酸奶、婴幼儿奶粉、老年奶粉产业链各环节价格在自身和彼此间具有显著双向波动溢出效应,但从显著性水平来看,牛奶产业链和婴幼儿奶粉产业链各环节间的双向波动溢出效应最为明显。     

Futures markets and price stabilisation: An analysis of soybeans markets in North America

The objective of this paper was to determine whether the futures markets have a stabilising or destabilising impact on soybean's spot prices in North America. Directed acyclic graphs (DAGs) are used to test for causality between futures prices, spot prices and ending stocks, followed by time series econometric analysis. The DAGs point to the two-way causal link between futures and spot prices and a lack of a causal link between inventory/stocks and spot price volatility. Time series results, including cointegration, vector error correction, impulse response and variance decomposition analysis, indicate a large impact from futures markets on the level and volatility of soybean spot prices in both the short and long run. These results have potentially important implications, as the impact of commodity price volatility is typically asymmetric across different actors. Farmers, for example, unlike speculators, utilise price risk management (PRM) instruments such as futures markets to mitigate price risks and appear to suffer from intensified volatility precisely because of their use of these instruments. Therefore, additional policies to cope with commodity price volatility, such as direct price controls or mitigation of consequences, can have critical stabilising functions supporting farmers' welfare and regional (rural) development.     

Fractional Integration in Agricultural Futures Price Volatilities

This article tests whether the volatility of agricultural futures prices exhibits fractional integration. Volatility series were constructed for fourteen agricultural futures price series with over 5,300 observations per series. The volatility series exhibit strong long-term dependence, which is an indicator of fractional integration. A fractional integration model, FIGARCH(1,  d , 1), performs significantly better than a traditional volatility model, GARCH(1,1), in modeling agricultural futures price volatility.     

Measuring the Volatility of Wheat Futures Prices on the LIFFE

Agricultural prices rose dramatically in 2007 and have subsequently fluctuated at high levels. This paper estimates the volatility of daily wheat futures prices on the Euronext/London International Financial Futures and Options Exchange for 1996–2012 using an exponential generalised autoregressive conditional heteroscedasticity model with a constant (price) elasticity of variance (CEV) and a broken trend. Results show that volatility is highly persistent; there is a structural break in volatility in June 2007 when volatility rose by 10%; subsequently, the wheat futures price has become more volatile; and the CEV is 0.04.     

Did Futures Markets Stabilise US Grain Prices?

Though economists are divided over whether, in practice, futures markets reduce spot price volatility, observers of nascent nineteenth century US futures markets essentially praised the stabilising effects of this financial innovation. Indeed, such praise is understandable, particularly if, as the Chicago Board of Trade (CBOT) and others assert, “violent” spot price fluctuations were common prior to, but not after, the 1870s; the same decade that grain trade historians typically associate with the birth of the modern futures contract. And whereas these events may be unrelated, the claim is intriguing because it requires that nineteenth century futures prices fulfil their price discovery function, a property that many modern futures markets do not possess. This paper explores what role, if any, the advent of futures trading may have had on spot price volatility. I corroborate the CBOT's assertion regarding diminished spot price volatility around the 1870s and show that early futures prices did indeed fulfil their price discovery function. Moreover, I address two alternative hypotheses that relate the decline in spot price volatility to the Civil War. Ultimately, I maintain that the evolution of futures markets is the principal proximate reason why commodity spot price volatility diminished.     

Volatility and Price Jumps in Agricultural Futures Prices—Evidence from Wheat Options

Evidence suggests that agricultural futures price movements have fat-tailed distributions and exhibit sudden and unexpected price jumps. There is also evidence that the volatility of futures prices is time-dependent both as a function of calendar-time (seasonal effect) and time to maturity (maturity effect). This article extends Bates' (1991) jump-diffusion option pricing model by including both seasonal and maturity effects in the volatility specification. Both in-sample and out-of-sample procedures to fit market option prices on wheat futures show that the suggested model outperforms previous published models. A numerical example shows the magnitude of pricing errors for option valuation.     

Information-rich wheat markets in the early days of COVID-19

This paper uses the information implicit in commodity futures and options prices to infer market beliefs about the impact of early-stages COVID-19 on commodity market fundamentals. The particular commodity examined is soft red winter (SRW) wheat, and the timeframe is early February to late March 2020. The analysis highlights various adjustments in the cash and futures price of SRW wheat in light of surging short-run demand from consumer hoarding of staple food products, and a weakening long-run market from growing wheat stocks and an emerging global recession. This split is causing the forward curve to flatten and basis levels to invert. The change over time in the price of options on wheat futures reveals increased price volatility in response to growing uncertainty about the COVID-19 impacts. Similarly, changes in the skewness of the option's volatility smile illustrate a shift in traders’ perception about risk in the right versus left tail of the price distribution.     

上海原油期货价格与我国新能源股价的相关性研究

选取上海原油期货和中证新能指数作为研究对象,以VAR模型为基础,分析了原油期货价格对新能源行业股价产生的引导作用,研究了上海原油期货与我国新能源行业股价的相关关系。研究结果表明:①上海原油期货价格的下跌会引起我国新能源行业股价的上涨,两者表现出反向变动;②上海原油期货价格对新能源行业股价的贡献率在不断提高,相互影响程度逐渐增强。     

Futures Markets and Spot Price Volatility: A Case Study

Futures markets, where they exist, can play a crucial role in determining the storage decision in the underlying spot (physical) market. The futures market acts as a conduit for market information and is a gatherer of agents' expectations about the future prospects for the spot market. As such, it is able to provide both price insurance and price discovery roles, the latter of which generates information for spot market traders and allows them to make rational storage decisions. If this were to be the case, then the efficiency of storage is improved which can potentially lead to a reduction in the volatility of spot prices over the marketing season. The existing literature is ambiguous as to whether futures markets can help spot markets price more efficiently. This paper seeks to examine whether this is the case in the British maincrop potato market by evaluating the volatility of spot prices over the period 1969–96 in a “before-after” analysis of the impact of the introduction of futures trading in 1980. The results suggest that the introduction of the futures market has led to a reduction in price volatility, despite some problems in the operation of the futures market itself.     

价格支持、政策调整及粮食市场波动

目的 为了估计价格支持政策对不同粮食品种期现货价格波动的直接影响,实证分析和比较了政策及其调整对粮食期现货价格波动实施效果的影响,为深化粮食价格形成机制改革提供一定的理论参考和实证支撑。方法 文章利用稻谷、小麦、玉米和大豆的现货与期货价格日数据,将政策以虚拟变量的形式引入GARCH模型实证分析最低收购价政策、临时收储政策及其调整对平抑粮食期现货市场波动的作用。结果 价格支持政策对粮食价格波动产生了显著影响,最低收购价政策能够明显降低稻谷和小麦现货市场的波动程度,但对期货市场波动的作用则相反;玉米和大豆临时收储政策的取消导致现货市场波动性提高,而对期货市场波动的影响存在差异。结论 价格支持政策具有降低价格波动的作用效果,政策调控效果与实施品种的国内供求及市场形势、国内外市场的联系程度密切相关,政策的完善还需关注对期货市场波动的影响。     

Destabilizing role of futures markets on North American hard red spring wheat spot prices

The objective of the paper is to determine if the futures prices of hard red spring wheat (HRSW) have stabilizing or destabilizing impact on spot HRSW price in North America. Several important results emerge from thorough empirical analysis. First, both Granger causality tests and directed acyclic graph algorithms (DAGs) point to two-way causality between futures and spot HRSW prices and thus endogeneity in both prices formation. To the contrary, both procedures suggest that ending stocks are exogenous to spot and futures HRSW prices. Both vector error correction model and impulse response functions point to a large and long-lasting impact of a shock to futures price on spot price level. Finally, variance decomposition analysis indicates that futures prices are responsible for the bulk of spot price volatility in both short and long run. Our result is consistent with those of theoretical models suggesting that when production (supply side) is the dominant disturbance, spot price is destabilized in both the short and the long run by futures prices. An important implication of this research is the need for alternative market mechanisms or alternative farm policy measures that would mitigate price risk and ensure sustainable farming of American HRSW farmers.     

A speculative bubble in commodity futures prices? Cross‐sectional evidence

Recent accusations against speculators in general and long-only commodity index funds in particular include: increasing market volatility, distorting historical price relationships, and fueling a rapid increase and decrease in the level of commodity prices. Some researchers have argued that these market participants—through their impact on market prices—may have inadvertently prevented the efficient distribution of food aid to deserving groups. Certainly, this result—if substantiated—would counter the classical argument that speculators make prices more efficient and thus improve the economic efficiency of the food marketing system. Given the very important policy implications, it is crucial to develop a more thorough understanding of long-only index funds and their potential market impact. Here, we review the criticisms (and rebuttals) levied against (and for) commodity index funds in recent U.S. Congressional testimonies. Then, additional empirical evidence is added regarding cross-sectional market returns and the relative levels of long-only index fund participation in 12 commodity futures markets. The empirical results provide scant evidence that long-only index funds impact returns across commodity futures markets.     

Causality and Efficiency in the Coffee Futures Market

Tests for causality and rationality in the coffee futures market were carried out using data from the New York Market. Tests of causality indicated that futures prices strongly influence variations in spot price eight weeks or more to maturity. However, beginning seven weeks to maturity there seems to be a strong causal relationship going from futures to spot and from spot to futures. Risk constancy or neutrality, equality of risk premium and spot price, and efficiency were rejected for the period 18, 51, and 33 weeks or more to maturity. However, simultaneity of risk neutrality and efficiency was accepted for contracts with 55-77 weeks to maturity. The general conclusion from this study is that coffee futures market can be used as an indicator of spot market prices for contracts with 55-77 weeks to maturity. While benefits can be obtained through short term adjustment of available stock and making use of quality storage facilities, planning longer term planting and marketing decisions (e.g., ≥ 77 weeks) on the basis of futures market price can result in misallocation of resources and welfare loss.     

Risk Management for Grain Processors and “Copulas”

The importance of calibrating hedging strategies for processors has escalated primarily due to the sharply increased volatility of futures, product, and by‐product prices. The purpose of this paper is to analyze price risk‐management strategies for wheat flour milling using copula distributions. While the application is for flour milling, it has similarities with other processing industries which confront one or more ingredients, one or more outputs, and futures for one of the commodities and/or products. The paper develops utility maximizing models encompassing expected return and risk. Alternative scenarios are evaluated. First, the models were used to derive optimal hedge ratios, as well as various measures of risk and return under alternative scenarios, and hedge durations. The results indicated hedge ratios are typically less than 1. The hedge ratios for the Mean‐value‐at‐risk (M‐VaR)‐Copula model increased with greater durations. Second, the VaR for the M‐VaR‐Copula was in most cases less than the noncopula specifications. Thus, noncopula models may over state risk as represented by VaR.     

Using Formula Prices in the Absence of Publicly Reported Prices: An Application for Segregated Early Weaned Pigs

A formula for deriving the price of segregated early weaned pigs using corn, soybean meal, and market hog prices was estimated by equating return on investment for the different phases of production. USDA reported prices were compared with prices derived from this and several other common formulas. Based on several accuracy measures, the estimated formula was better at predicting spot-market prices than other formulas. Producers appear to form price expectations based on futures plus expected basis rather than simply futures or current cash prices. However, the method of choosing price expectations will depend on the risk attitudes of the buyer and seller and their business relationship. Developing pricing formulas based on the framework outlined here (equal returns on investment) has merit for establishing prices in the absence of publicly reported information. However, it is important that users of the formula understand the conceptual framework of how and why it was developed.     

Returns to smallholder dairying in the Kilimanjaro region,Tanzania

Tanzania is a net importer of dairy products despite its large cattle herd and successive government efforts to promote dairying. This paper draws on survey data to examine the financial attractiveness of dairying to smallholders in an area of high dairy potential on the slopes of Mount Kilimanjaro. On mixed farms in which coffee and bananas are the other main enterprises, producers keep small herds of mainly crossbred and grade cattle, mostly fed in stalls on cut forage and crop residues. Using a herd model, a benefit-cost analysis of dairying was carried out. This showed that at prevailing prices, returns to dairying were around 20%. There was, however, no difference in the returns gained by the larger scale farmers who had more of the grade cows and managed them intensively, compared to those using a less intensive system with lower potential stock. Moreover, the profitability of dairying for the former was underwritten by subsidies on inputs and fuel which are difficult to justify. Policy has apparently over-emphasised improving yields and the development of intensive dairying, and has not been sufficiently concerned with keeping down the costs of dairying.     

Renewable versus nonrenewable resources: an analysis of volatility in futures prices

This study outlines a new approach for differentiating commodity futures based on their exhaustibility. Various aspects of volatility in the futures prices of renewable resources (palm oil, coffee, soya beans, rice, wheat and corn) and nonrenewable resources (zinc, aluminium, natural gas, gold, crude oil and copper) are studied, exploring whether volatility is greater in the former than in the latter. We use a generalised autoregressive conditional heteroskedasticity (GARCH) model to test our main hypothesis that the volatility in futures prices for renewable resources has recently been equal to or greater than the volatility in futures prices for nonrenewable resources. Our key findings suggest that futures prices for some renewable resources have greater variance than those for benchmark crude oil in a simulated GARCH series. We extend our analysis using a nonlinear vector smooth transition autoregressive (VSTAR) model to test for the existence of a shifting‐mean tendency in the commodity series that we researched. We show that transition from a stable to a volatile regime is more abrupt for renewable resources.     

Profitability of incremental generic promotion of Australian dairy products

The motivation for this study rests on two factors. First, Australian dairy farmers spend around $20 million annually on generic promotion and estimates of the returns from this expenditure are required to facilitate efficient investment decisions. Second, while the Australian dairy industry has been highly regulated, there has been a substantial reduction in assistance over the past decade and farm‐gate milk prices were deregulated on 1 July 2000. The profit potential of promotion may vary with the degree of regulation, so past estimates of the returns from promotion may not hold in the competitive environment of the future. Hence, the aim of this study is to examine the effects of government intervention on the profitability for dairy farmers of incremental changes in generic dairy promotion expenditure using a perfectly competitive market as a reference point. Competitive market price and quantity outcomes for the Australian dairy industry are estimated. The impacts of increments in dairy product and competing product generic promotion expenditures on dairy farmers’ profits are assessed using equilibrium displacement modelling. Finally, graphical procedures are used to examine the effects of dairy industry regulation on the profitability of dairy promotion.     

Alcohol Tax,Price–Quality Proxy and Discounting: A Reason Why Alcohol Taxes May Rebound

The increasing concern about the external costs of alcohol consumption has often led economists and policy‐makers to advocate taxes to internalise the social costs and target consumption. However, in certain markets for alcoholic drinks – particularly wine – price is not only a cost but also an indicator of quality, guiding consumer choice. There is, perhaps, a higher probability of ex post satisfaction with products at higher prices in a market with potential adverse selection. The price–quality proxy interacts with discounts, where the full price of the product before discount (referred to as the External Reference Price in the marketing literature) is used as a quality reference. This study shows that an alcohol tax in the presence of discounting may increase the perceived value of the product, and therefore persuade consumers to prefer the purchase of more expensive wines with the highest discount. As a consequence, consumers could favour products with higher alcohol content – which contradicts the objectives of the policy. Consequently, for an alcohol tax to be effective discounting of alcoholic beverages (in particular, wine) should be regulated to avoid the policy backfiring.     

Hedging Opportunities for Canadian

The unprecedented commodity price volatility in the last decade has resulted in a growing interest in futures trading by farmers. One of the major reasons often provided for the usefulness of commodity futures markets is that they provide a mechanism whereby producers can shift the risk of price change onto others. Interestingly, little research has been conducted on the effectiveness of the WCE as a hedging tool for farmers.
The objective of this paper was to investigate the extent to which the futures contracts for rapeseed, barley and flaxseed can be used by farmers in order to reduce price risk (measured by volatility). Drawing on earlier literature, the theory of hedging was reviewed and formulae for estimating the optimal hedge and the effectiveness of hedging were presented. An empirical analysis determined that the Winnipeg rapeseed, barley and flaxseed futures contracts are very useful in terms of allowing a producer the opportunity to reduce exposure to price risk.