COVID-19 and tail risk contagion across commodity futures markets

This paper examines the impact of COVID-19 on tail risk contagion across commodity futures markets using a copula-based network method. We document a significant increase in the lower and upper tail contagiousness of commodities following the COVID-19 outbreak. Contagion shows an obvious clustering characteristic, that is, there is higher tail risk connectedness between commodities in the same category. Agricultural commodities are significantly less contagious than metals and energy commodities; soft commodities in particular can offer investors significant diversification benefits. There are several hub commodities in the contagion network, chief among them copper, which are good transmitters of shocks and should be treated with caution by investors and regulators. Although tail risk and contagiousness of individual commodities increase together during the pandemic, we find a negative cross-sectional relationship between tail risk and contagiousness, that is, commodities with high tail risk are not necessarily highly contagious and may even be less so.     

On commodity price limits

This paper examines the behavior of futures prices and trader positions around the occurrence of price limits in commodity futures markets. We ask whether limit events are the result of shocks to fundamental volatility or the result of temporary volatility induced by the trading of noncommercial market participants (speculators). We find little evidence that limits events are the result of speculative activity, but instead associated with shocks to fundamentals that lead to persistent price changes. When futures trading halts price discovery migrates to options markets, but option prices provide a biased estimate of subsequent future prices when trading resumes.     

Global commodity and equity markets spillovers to Africa during the COVID-19 pandemic

This paper examines the connectedness among 12 African equity markets and the global commodity, developed equity markets, paying particular attention to their evolution during the COVID-19 pandemic's peak period. We find that whilst African equity markets connect weakly to these markets, the levels of connectedness among these markets improved significantly during the pandemic. In addition, the energy market dominates the transmission of shocks in the system with commodity markets. Regarding the system with equity markets, the French and South African equity markets transmit the highest spillover in the full sample and during the pandemic's peak period, respectively.     

Commodity momentum decomposition

This study decomposes the momentum factor (MOM) in the commodity futures market. A high-to-price (HTP) factor generates a higher Sharpe ratio than a price-to-high (PTH) factor. We uncover that the profitability mechanisms across three momentum factors are different. The positive returns on MOM and PTH are associated with overconfidence and strong self-attribution. In contrast, HTP is linked to investors' underreaction and the information diffusion process. Moreover, we find that positive demand shocks raise the return on HTP.     

The market quality of commodity futures markets

To study the market quality of commodity futures markets, we construct a commodity futures market quality index from the perspective of liquidity, efficiency, and volatility. Based on the market quality index, the Chinese commodity futures market operates steadily. The metal futures market is more efficient and stable than the market for agricultural futures. The Chinese commodity futures market is less liquid and more volatile than the U.S. market. We examine the determinants of market quality and find that macroeconomic variables and futures market contracts are significantly related to the market quality of Chinese commodity futures.     

The response of volume and returns to the information shocks in China's commodity futures markets

This study investigates the response of returns and volume to different information shocks in China's commodity futures markets using bivariate moving average representation (BMAR) and bivariate vector autoregression (BVAR) methodologies. Consistent with the conclusions from stock market studies that have used these methodologies, it is found that the informational/permanent components are the dominant components for returns movements, and the noninformational/transitory components are the dominant components for trading volume. It is also found that the market response of copper futures improved during the sample period, and the market responses of actively traded futures (copper and soybeans) are better than those of the less actively traded futures (aluminum and wheat). © 2005 Wiley Periodicals, Inc. Jrl Fut Mark 25:893–916, 2005     

投资主体对我国农产品期货效率的影响

为了促进我国农产品期货市场的完善与发展,提高我国农产品期货市场的效率,对影响我国农产品期货市场效率的投资主体因素进行了具体分析。指出我国农产品期货市场投机者过多、套期保值者少、战略机构投资主体缺失等投资主体结构对期货市场效率的影响。提出引导农民合作组织进入期货市场、引导农业订单公司进入农产品期货市场、逐步放宽对国有企业参与期货市场的限制、积极发展我国的期货投资基金等具体政策建议。     

A cointegrated commodity pricing model

We propose a commodity pricing model that extends the Gibson–Schwartz two‐factor model to incorporate the effect of linear relations among commodity spot prices, and provide a condition under which such linear relations represent cointegration. We derive futures and call option prices for the proposed model, and indicate that, unlike in Duan and Pliska (2004), the linear relations among commodity prices should affect commodity derivative prices, even when the volatilities of commodity returns are constant. Using crude oil and heating oil market data, we estimate the model and apply the results to the hedging of long‐term futures using short‐term ones.     

THE EFFECT OF TRADING FUTURES ON SHORT SALE CONSTRAINTS

It is commonly believed that the trading of futures on a commodity enables the market to overcome short selling constraints on the spot commodity itself. This belief is embedded in the notion that trading strategies involving futures contracts enable traders to replicate the payoffs as if they were short the spot commodity. The purpose of this paper is to investigate this common belief in a general arbitrage‐free semimartingale financial model with trading in futures and a short selling prohibition on the spot commodity. We show via various examples that, in general, this common belief is incorrect. Furthermore, we provide a set of sufficient conditions, albeit very restrictive, under which the common belief is true.     

Dependence of stock and commodity futures markets in China: Implications for portfolio investment

We examine the recent trends in dependence structure between the fast-growing commodity markets and the stock markets in China. We address this issue by using copula functions that allow for measuring both average and tail dependence. Our results provide evidence of low and positive correlations between these markets, suggesting that commodity futures are a desirable asset class for portfolio diversification. By comparing the market risks of alternative portfolio strategies, we show that Chinese investors can take advantage of commodity futures during different times to realize risk diversification and downside risk reduction benefits.     

Efficient use of commodity futures in diversified portfolios

We provide evidence on the role of commodity futures in portfolios comprised of stocks, bonds, T‐bills, and real estate. Over the period investigated (1973–1997), Markowitz optimization over a range of risk levels gives substantial weight to commodity futures, thereby enhancing the portfolios’ returns. We find dramatically different results when we use a simple ex ante measure of monetary stringency to dichotomize the sample into expansive‐versus‐restrictive monetary‐policy periods. In periods characterized by restrictive monetary policy, commodity futures are shown to have substantial weight in the efficient portfolios, with significant return enhancement at all levels of risk. In periods characterized by expansive monetary policy, commodity futures are shown to have little or no weight in the efficient portfolios, with no return enhancement at all levels of risk. © 2000 John Wiley & Sons, Inc. Jrl Fut Mark 20:489–506, 2000     

Managed futures,positive feedback trading,and futures price volatility

A major issue in recent years is the role that large, managed futures funds and pools play in futures markets. Many market participants argue that managed futures trading increases price volatility due to the size of managed futures trading and reliance on positive feedback trading systems. The purpose of this study is to provide new evidence on the impact of managed futures trading on futures price volatility. A unique data set on managed futures trading is analyzed for the period 1 December 1988 through 31 March 1989. The data set includes the daily trading volume of large commodity pools for 36 different futures markets. Regression results are unequivocal with respect to the impact of commodity pool trading on futures price volatility. For the 72 estimated regressions (two for each market), the coefficient on commodity pool trading volume is significantly different from zero in only four cases. These results constitute strong evidence that, at least for this sample period, commodity pool trading is not associated with increases in futures price volatility. © 1999 John Wiley & Sons, Inc. Jrl Fut Mark 19: 759–776, 1999     

How about selling commodity futures losers?

This paper explores the benefits of extending the investment universe to commodity futures, from the perspective of momentum traders. We find that the growth-optimal portfolio includes negative (positive) weights on commodity futures losers (stock winners). Motivated by this finding, we construct a joint momentum strategy, buying stock winners and selling commodity futures losers, and show that it generates an average monthly return of up to 1.91% and provides much lower skewness (0.04) and kurtosis (1.27) than a traditional stock momentum strategy. It also greatly improves profitability, especially in unfavorable market states, and thus effectively manages tail risk.     

影响我国农产品期货效率的国际化因素与对策

为了进一步促进我国农产品期货市场的完善和发展,推动我国农产品期货市场国际化,并在国际农产品期货市场中具有世界影响力,对影响我国农产品期货市场效率的国际化因素进行了具体分析,指出当前我国农产品期货市场在国际化、开展跨境业务等方面存在的一些问题。提出逐步允许更多的国内公司直接参与国际期货交易．逐步拓展国内期货公司代理国外期货交易以及探索国外投资者参与国内期货交易的途径等具体政策建议。     

Speculative pressure

The paper investigates the information content of speculative pressure across futures classes. Long-short portfolios of futures contracts sorted by speculative pressure capture a significant premium in commodity, currency, and equity markets but not in fixed income markets. Exposure to commodity, currency, and equity index futures’ speculative pressure is priced in the broad cross-section after controlling for momentum, carry, global liquidity, and volatility risks. The findings are confirmed by robustness tests using alternative speculative pressure signals, portfolio construction techniques, and subperiods interalia. We argue that there is an efficient hedgers-speculators risk transfer in commodity, currency, and equity index futures markets.     

Samuelson hypothesis,arbitrage activity,and futures term premiums

The Samuelson hypothesis asserts that futures volatility increases as maturity decreases. On the basis of 10 US commodity futures and by capturing the dynamics of the futures volatility terms structure with three factors, we show that in most markets the slope factor is strongly negative in certain periods and at best only weakly negative in other periods. High inventory levels are found to correspond to flatter volatility term structures in seven futures. This finding is consistent with the linkage between carry arbitrage and the Samuelson hypothesis. We also find that a flatter volatility term structure corresponds to lower absolute futures term premiums.     

TIME‐CHANGED ORNSTEIN–UHLENBECK PROCESSES AND THEIR APPLICATIONS IN COMMODITY DERIVATIVE MODELS

This paper studies subordinate Ornstein–Uhlenbeck (OU) processes, i.e., OU diffusions time changed by Lévy subordinators. We construct their sample path decomposition, show that they possess mean‐reverting jumps, study their equivalent measure transformations, and the spectral representation of their transition semigroups in terms of Hermite expansions. As an application, we propose a new class of commodity models with mean‐reverting jumps based on subordinate OU processes. Further time changing by the integral of a Cox–Ingersoll–Ross process plus a deterministic function of time, we induce stochastic volatility and time inhomogeneity, such as seasonality, in the models. We obtain analytical solutions for commodity futures options in terms of Hermite expansions. The models are consistent with the initial futures curve, exhibit Samuelson's maturity effect, and are flexible enough to capture a variety of implied volatility smile patterns observed in commodities futures options.     

基于商品期货条件下的批发组织结构调整

本文从商品期货在市场经济中发挥的作用与功能出发,阐述了国内传统的流通批发组织随着商品期货交易的成熟将普遍面临生存危机,并结合国外商品期货发达国家的流通批发组织运行情况,提出了国内流通批发组织的结构调整方案。     

Modeling seasonality in agricultural commodity futures

The stochastic behavior of agricultural commodity prices is investigated using observations of the term structures of futures prices over time. The continuous time dynamics of (log‐) commodity prices are modeled as a sum of a deterministic seasonal component, a non‐stationary state‐variable, and a stationary state‐variable. Futures prices are established by standard no‐arbitrage arguments and the Kalman filter methodology is used to estimate the model parameters for corn futures, soybean futures, and wheat futures based on weekly data from the Chicago Board of Trade for the period 1972–1997. Furthermore, in a discussion of the estimated seasonal patterns in agricultural commodity prices, the paper provides empirical evidence on the theory of storage that predicts a negative relationship between stocks of inventory and convenience yields; in particular, convenience yields used in this analysis are extracted using the Kalman filter. © 2002 Wiley Periodicals, Inc. Jrl Fut Mark 22:393–426, 2002     

Commodity tail risks

In this study, we investigate the cross-section of option-implied tail risks in commodity markets. In contrast to findings from equity markets, left and right tail risks implied by option markets are both large. Commodity-specific variables exert the largest influence on tail risk, while there is no evidence of systematic commodity factors that are linked to tail risk. Additionally, we find strong links to the equity markets, but also comovements to macroeconomic factors. Left or right tail risks are largely independent of variance risk premiums. Finally, both left and right tail risks are priced in the cross-section of commodity futures returns.