中国碳排放权交易市场收益率波动性特征研究

以北京、上海、广东、湖北和重庆碳排放权交易市场为研究对象,运用GARCH族模型研究中国碳排放权交易市场收益率波动性特征。结果表明,5个碳排放权交易市场收益率的波动聚集性、持续性表现不完全一致;北京、上海和重庆存在负向的杠杆效应,广东和湖北不存在杠杆效应;从波动溢出效应关系看,5个碳排放权交易市场间的整体联动性不强;运用方差比率检验法得出,5个碳排放权交易市场均未达到弱势有效市场。这些特征反映出中国碳排放权交易市场的运行机制仍然存在缺陷,建议加强顶层设计,完善碳排放权交易体系。     

The Role of Index Trading in Price Formation in the Grains and Oilseeds Markets

We use both Granger‐causality and instrumental variables (IV) methods to examine the impact of index fund positions on price returns for the main US grains and oilseed futures markets. Our analysis supports earlier conclusions that Granger‐causal impacts are generally not discernible. However, market microstructure theory suggests trading impacts should be instantaneous. IV‐based tests for contemporaneous causality provide stronger evidence of price impact. We find even stronger evidence that changes in index positions can help predict future changes in aggregate commodity price indices. This result suggests that changes in index investment are in part driven by information which predicts commodity price changes over the coming months.     

Market interdependence and volatility transmission among major crops

This article provides a comprehensive analysis of the dynamics of volatility across major agricultural commodities in the United States. Volatility interactions across markets may lower the effectiveness of diversification strategies to mitigate price risks and should be taken into account when analyzing the pricing behavior of different agricultural commodities. We follow a multivariate GARCH approach to evaluate the time evolution of conditional correlations and volatility transmission across corn, wheat, and soybeans price returns on a daily, weekly, and monthly basis. The period of analysis is from 1998 to 2012. The estimation results indicate a lack of lead‐lag relationships between corn, wheat, and soybeans price returns at the mean level. We find, however, important volatility spillovers across commodities, particularly at the weekly and monthly level. Wheat and corn seem to play a major role in terms of volatility transmission. Despite the supposed higher financial market integration of agricultural commodities, we do not observe that agricultural markets have become more interdependent in recent years.     

What Does Granger Causality Prove? A Critical Examination of the Interpretation of Granger Causality Results on Price Effects of Index Trading in Agricultural Commodity Markets

The influence of index trading on price levels, returns, spreads or volatility in agricultural commodity markets is frequently investigated with bivariate Granger Causality (GC) tests. A joint review of existing empirical studies reveals scant and inconsistent evidence of GC from index activity to prices. Some findings of reverse GC from prices to index activity are reported. The literature offers three different interpretations of GC test results: (i) as prima facie causal evidence; (ii) as a test for informational efficiency of the markets; or (iii) as a test for the ability of one variable to improve the forecast of another variable. A critical examination of these interpretations against an extended theoretical background reveals that none allows direct inferences about the existence or absence of an influence from index trading activity on the price mechanism in the market. This severely limits the usefulness of a stand‐alone application of GC tests.     

Comovement of dairy product futures and firm value: returns and volatility

This study investigates the exposure of dairy firm stock prices to the prices of dairy product futures, in terms of returns and volatility, from May 2013 to April 2018. Stock price returns are regressed against an index of the futures price returns to four dairy products – milk, cheese, butter and dry whey – to isolate the effects of the dairy futures price returns. Dairy product futures price returns are found to be significant in the regression in the first three years of the sample period, with a mean coefficient of ?0.024. Using the Diebold‐Yilmaz volatility spillover method of forecast error variance decomposition, we show that the volatility of the four dairy product futures accounted for an average of 5.49 per cent of the volatility of dairy stock prices. These results suggest that the prices of dairy firms have minimal exposure to dairy product futures prices. This has implications for dairy firms and investors, who seek to understand volatility and returns in the dairy products and the stocks they trade in, and for policymakers, who seek to control or mitigate undesirable dairy product price volatility.     

Asymmetric price volatility transmission between food and energy markets: The case of Spain

The proportion of agricultural production that is being transformed into biofuels has been growing worldwide over the last decade. This has spurred the food versus fuel debate. This article aims at shedding light on this issue by studying price volatility relationships between food and biofuel prices in Spain. We use an asymmetric MGARCH model to evaluate volatility spillovers between the Spanish biodiesel blend and refined sunflower oil prices. Empirical results confirm that there are bidirectional and asymmetric volatility spillovers between these two prices.     

Financial activity in agricultural futures markets: evidence from quantile regressions

This study analyses the relationship between financial activity and price returns in 12 US agricultural futures markets. It contributes to the existing research by exploring the forecasting power of trading activity for returns from the perspective of conditional quantiles. Quantile regressions detect Granger‐causal effects from positions of speculators and index traders to price returns in a wide range of commodity markets such as cocoa, coffee, corn, sugar and SRW wheat.     

Price Dynamics in a Vertical Sector: The Case of Butter

We develop a reduced-form model of price transmission in a vertical sector, allowing for refined asymmetric, contemporaneous and lagged, own and cross-price effects under time-varying volatility. The model is used to investigate the wholesale-retail price dynamics in the U.S. butter market. The analysis documents the nature of nonlinear price dynamics in a vertical sector. It finds strong evidence of asymmetric retail price responses, both in the short term and the longer term, but only weak evidence of asymmetric wholesale price responses. Asymmetric retail responses play a major role in generating a skewed distribution of butter prices. The empirical results indicate the presence of imperfect competition at the retail level.     

When China strikes: Quantifying Australian companies' stock price responses to China's trade restrictions

In early 2020, China, Australia's top export market, unilaterally imposed trade restrictions on Australian barley, beef, coal, cotton, timber, copper and wine. However, convincing evidence regarding the effects of such trade restrictions on firms is scarce. Leveraging data on daily stock returns from 20 listed Australian and 32 listed Chinese firms that produce the restricted commodities, we provide the first systematic analysis of the firm-level economic impacts of China's trade restrictions on Australian and Chinese firms. We find significant adverse effects on Australian firms' stock returns, leading to almost 20% loss within 10 trading days; however, most firms' stock returns immediately rebounded. In contrast, Chinese firms usually saw significant positive stock returns, leading to almost 30% gains, and the positive abnormal returns continuously increased within 10 trading days. Media coverage and trade dependence substantially impact Australian and Chinese firms' stock returns—industries with stronger trade dependence on China saw greater losses in Australian firms' stock returns. Our results suggest that trade reallocation and deflection are two effective mitigation mechanisms for Australian exporters facing China's trade restrictions.     

Ride the trend: Is there spread momentum profit in the US commodity markets?

Some previous researchers have argued that trading strategies based on calendar spread time series momentum (STSM) can deliver significant returns (Szymanowska et al. 2014; Boons and Prado 2019), which, if true, is at odds with the efficient market hypothesis. These arguments however, do not exclude the unrealisable futures contract roll yield and are also affected by other empirical and statistical issues that may lead to misleading results. With more than 30 years of data, we investigate STSM in 22 US commodity futures markets. First, we assess whether past spread returns can predict future returns, a necessary condition for the existence of momentum. We find predictability to be very weak after correcting for the issues affecting prior research. Second, we implement STSM-based investment strategies. We compare STSM profits for individual markets and portfolios to profits generated by a simple long-only benchmark strategy that does not require any predictability. STSM does not generate returns statistically different from the benchmark trading strategy, with both strategies generating very low or negative returns. For the momentum to outperform the benchmark strategy, predictability should be three times larger than observed from real data, but would entail substantial downside risk. In sum, the empirical evidence indicates that returns from STSM-type strategies are illusive for the commodities and period studied. Our results strongly suggest that inclusion of unrealisable roll yield generates the illusion of profitable STSM trading strategies in previous research.     

Do nonrenewable-energy prices affect renewable-energy volatility? The case of wood pellets

Over the past decade, the U.S. Southeast has experienced a rapid expansion of wood-pellet biomass production for European export. This renewable wood-pellet supply requires nonrenewable-energy inputs in its manufacturing and logistics, which suggests possible price-volatility spillovers between renewable and nonrenewable markets. A BEKK-MGARCH model is employed for investigating these possible price-volatility spillovers. Overall, results suggest a limited negative effect of past volatile nonrenewable-energy prices influencing current wood-pellet price volatility. Specifically, high volatilities in nonrenewable-energy prices do not affect the volatility of wood-pellet prices. Thus, any stability concerns in terms of nonrenewable-input prices affecting the wood-pellet market are not warranted.     

Food–oil volatility spillovers and the impact of distinct biofuel policies on price uncertainties on feedstock markets

Over recent decades, the link between crude oil and agricultural markets has been reinforced following the introduction of biofuels. We use timely measures of (co)variation spillovers to analyze the role of crude oil in shaping price uncertainties of agricultural commodities, which are largely used as biofuel feedstocks. Our sectoral- and market-specific measures distinguish tranquil (1995–2005) and crisis episodes (2006–2015), as well as periods during which either consumption mandates or tax credits were enacted to spur biofuels. During the crisis period, crude oil volatility transmissions account for 16% (20%) of price uncertainties in ethanol (biodiesel) feedstock markets on average. Moreover, we find evidence of enhanced volatility transmissions under tax credit regimes compared with consumption mandates. The results from pooled regressions confirm stronger volatility transmissions by about 12% under the enactment of tax credits.     

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.     

Offsetting legal deficits of native vegetation among Brazilian landholders: Effects on nature protection and socioeconomic development

The Brazilian native vegetation supports essential ecosystem services and biodiversity for the global society, while land use competition may intensify around the increasing needs for food, fibre and bioenergy. The Brazilian Forest Act of 2012 amplified a market-based mechanism for offsetting native vegetation deficits in private farmlands. This mechanism enables a large-scale trading system allowing landholders to offset their own deficits of native vegetation by purchasing certificates associated with a surplus of native vegetation from other landholders. This mechanism is an alternative for the more expensive restoration of native vegetation on own land. The launching of the mechanism now depends on specific regulations at state level, which may include geographical restrictions for offsetting deficits. The aim of this study is to evaluate the effects in nature protection and socio-economic development of different offsetting implementation alternatives. Our findings suggest that in a business-as-usual scenario the offsetting mechanism may have little or no additional effects on protection of native vegetation, because most of the offsetting is likely to take place where native vegetation is already protected by prevailing legislations. We concluded that it is possible to maximise environmental and socio-economic returns from the offsetting mechanism without undermining productive land. This would be possible if regulations ensure additionality in nature protection while enabling a self-sustaining mechanism for income generation for small-scale family farmers in the poorest region of Brazil, protecting biodiversity and counteracting major trade-offs between ecosystem services.     

Group heterogeneity and the economic effect of farmer organisation participation: Empirical evidence from Taiwan

We explore the effects of different farmer organisations on smallholder farmers' economic performance. The average treatment effect of switching between different farmer organisations is examined. In addition, based on the premise that a higher level of social capital is accumulated through participation in multiple farmer organisations, we also investigate how the economic consequences of farmer organisation membership vary with the intensity of participation. Our conceptual model explicitly includes social capital to provide a micro-foundation and a theoretical justification for the linkage between farmer organisation participation and the economic outcome. This indicates that participating in different types of farmer organisations is beneficial for farm households only when the returns from social capital investment outweigh the time cost of participation. Our empirical results suggest that membership of farmer organisations that are more homogeneous in terms of member specialty and similarity in production and marketing activities results in a significant increase in farm sales revenue and net returns. This result supports the view that technological proximity accentuates knowledge spillovers within the farmer organisations, and thus leads to better economic outcomes. In line with the prediction of the theoretical model, the average treatment effect of participation is found to increase with the number of organisations that farmers belong to. Moreover, results from the quantile regression provide empirical evidence supporting increasing returns to social capital accumulated through participation in several farmer organisations.     

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.     

The Term Structure of Implied Forward Volatility: Recovery and Informational Content in the Corn Options Market

Using a flexible method, we develop the term structure of volatility implied by corn futures options with differing maturities, and evaluate its ability to predict subsequent realized price volatility. The implied forward volatilities anticipate realized volatility well. For the nearby interval, the implied forward volatilities provide unbiased forecasts, and are superior to forecasts based on historical volatilities. For more distant intervals, early-year options predict the direction and magnitude of future volatility changes about as well as a three-year moving average and better than a naïve forecast. However, later-year options display less forecast power in part due to reduced trading activity.     

Farmland cash rents and the dollar

We explore whether the U.S. exchange rate could have an influence on cash rental rates for farmland in five U.S. cornbelt states. We find that farmland cash rents have a fairly strong, positive correlation with the U.S. dollar, in terms of its real value relative to major agricultural trading partners. One explanation for the correlation is that a strong dollar lowers the price of key inputs and thus has purchasing power effects. A strong dollar may therefore be associated with higher net returns, and the payment of higher cash rents by farmers. We find support for this hypothesis through a series of econometric models.     

Do Farmers Internalise Environmental Spillovers of Pesticides in Production?

Pesticides are used in agriculture to protect crops from pests and diseases, with indiscriminate pesticide use having several adverse effects on the environment and human health. An important question is whether the environmental spillovers of pesticides also affect the farmers’ production environment. We use a model of optimal pesticide use that explicitly incorporates the symmetric and asymmetric effect of pesticides’ environmental spillovers on crop production. The application focuses on panel data from Dutch cash crop producers. We show that pesticides have a positive direct impact on output and a negative indirect impact through their effects on the production environment.     

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.