Stock markets’ bubbles burst and volatility spillovers in agricultural commodity markets

Our paper focuses on commodity financialization and the gradual integration between commodity and financial markets, investigating to what extent shocks in stock markets impact commodity price volatility, and the persistency of the phenomenon. To this end, we estimate Volatility Impulse Response Function from stock markets to agricultural commodity markets over a symmetric window before and after two of the most important bubble bursts since the new millennium, the 2000 dot.com bubble and the 2008 financial crises. Results highlight that volatility spillover increased significantly after the 2008 financial crises, signalling a rising interconnection between financial and agricultural commodity markets.     

The Relationship Between Energy Commodity Prices and Electricity and Market Index Performances: Evidence from an Emerging Market

We investigate the effect of energy commodity price movements on market and electricity index returns in Turkey for the periods before, during, and after the year 2008. Although the Turkish economy is highly reliant on oil, we find that oil price does not lead either electricity or market indexes. This might be attributable to sluggish integration of financial markets in Turkey compared to developed markets. Natural gas price leads electricity index in the pre-2008 period. Its significance is reduced following the decline in natural gas usage in electricity production. This suggests that commodity dependence may be driving the link between commodity and asset prices in related sectors.     

中国大宗商品期货市场定价机制研究

大宗商品期货市场是我国资本市场的重要组成部分,其定价有效性关系到投资者套期保值和价格发现等功能的实现。本文对国际前沿研究中常用的定价因子进行全面系统梳理,并对这些因子对我国商品期货合约收益率的解释和预测能力进行检验。在此基础上,本文构建了适用于我国大宗商品期货市场的包含市场、基差以及基差动量的三因子定价模型。进一步研究表明,基于大宗商品存储理论和现货存货数据构建的投资组合收益率可以被本文三因子模型有效解释,验证了经典的存储理论在我国的适用性。此外,本文对基差与基差动量两个重要因子的经济学意义进行了阐释。本文研究为进一步厘清大宗商品期货市场定价机制提供了一定参考。     

Systemic risk of commodity markets: A dynamic factor copula approach

This study aims to measure the systemic risk of commodity markets and investigate its causal relationship with the macroeconomy. First, we propose a novel measure called the joint probability of abnormal changes (JPAC) to measure the systemic risk of commodity markets. Second, we introduce two new measures, the expected proportion of commodities in abnormal price change (EPAPC) and the contribution to systemic risk (CSR), to identify the systemic importance of each commodity. Third, we examine the relationship between JPAC and some key macroeconomic variables using mixed-frequency Granger causality tests. We conduct an empirical study using 24 commodity indices from 2015 to 2021. Our results reveal that: (1) JPAC can well capture the risk events in the real world; (2) the systemic risk of commodity markets has increased significantly since the start of the US-China trade war; (3) EPAPC and CSR indicate that energy commodities have higher systemic importance than others and are most likely to cause market fluctuations; and (4) some causal relationships between the systemic risk of commodity markets and the macroeconomy are identified. Overall, this study improves our understanding of systemic risk in commodity markets and provides important implications for policymakers in China and the US.     

WHY DO STOCK PRICES DECLINE IN RESPONSE TO EMPLOYEE LAYOFFS? UK EVIDENCE FROM THE 2008 GLOBAL FINANCIAL CRISIS

Employee layoff decisions made during adverse economic conditions are expected to signal poor investment opportunities, but layoffs undertaken during prosperous markets should be efficiency enhancing. We examine layoffs during the global financial crisis of 2008 and compare this with an earlier period of economic prosperity. We find a positive market reaction to layoffs during rising financial markets but stock price declines following employee layoffs during the 2008 financial crisis. These price effects occur irrespective of the stated reason for the layoff and the industry of the announcing firm, and are mirrored in our robustness test of an earlier period.     

Soft commodities and the global financial crisis: Implications for the economy,resources and institutions

Over the past decade, soft commodities have been subjected to increasing speculative price fluctuations. Following the 2008 financial crisis, most studies have highlighted causal relationships between price volatility, derivative and future markets for underlying financial assets as well as agricultural and mineral commodities. This article investigates the multifaceted effects of unrestrained financialization of the resources and goods markets and its implications for agricultural markets and soft commodities for purposes other than direct human consumption. We place a particular emphasis on the process of commodification of food and non-food crops and their use as green source of liquid fuels (i.e. soy, sugar cane, palm oil, jatropha, and canola). It is argued that speculation in financial markets has led to spillover effects across commodity and resource markets. More importantly, speculation and price volatility in the commodity markets has had a direct bearing on the resource markets and organization and appropriation of common-pool resources. The article sheds further light on the causal relationship between derivative markets, hedging techniques, financial yields and price volatility and spillover effects in the market for food and soft commodities.     

Evidences for a structural change in the oil market before a financial crisis: The flat horizon effect

There are growing evidences that the commodity bubble in the 2000s had a major impact in the 2007–08 financial crisis. A salient feature of this commodity bubble was the dramatic increasing in the correlation of indexed commodities with oil price following the financialisation of the oil market. In this paper we suggest that, besides the growing demand from emerging economies and the following inflow of money from speculative traders, the introduction of the electronic platform could have had an important and underestimated effect on the oil market. Our analysis of the spot and futures oil prices at the NYMEX based on the Generalized Hurst Exponent confirms that the period 2004–2007 is pivotal in the oil market and corroborates the hypothesis that a structural change occurred in both markets. The evident decrease in multifractality suggests a flattening of the time horizon in financial oil markets and the coexistence of long-termism and short-termism. This structural change could partially explain the observed increase of correlations between commodities and oil price.     

Seasonality and the valuation of commodity options

Price movements in many commodity markets exhibit significant seasonal patterns. However, given an observed futures price, a deterministic seasonal component at the price level is not relevant for the pricing of commodity options. In contrast, this is not true for the seasonal pattern observed in the volatility of the commodity price. Analyzing an extensive sample of soybean, corn, heating oil and natural gas options, we find that seasonality in volatility is an important aspect to consider when valuing these contracts. The inclusion of an appropriate seasonality adjustment significantly reduces pricing errors in these markets and yields more improvement in valuation accuracy than increasing the number of stochastic factors.     

Investor structure and the informational efficiency of commodity futures prices

This article investigates the impact of the trading positions of hedgers (i.e., producers, merchants, processors, or users of a commodity), speculators (i.e., commodity pool operators, trading advisors, or hedge funds), and swap dealers on the price formation process in the agricultural, metal, and energy futures markets. The hedgers' relative positions exert negative impacts on price efficiency in commodity futures markets. Hedgers are less likely to be information motivated, so their trading delays the price formation process. However, speculators' positions have positive impacts on price efficiency because speculators correct pricing errors. This study also offers evidence that the role of swap dealers, similar to speculators in futures markets, is to provide liquidity and cross-market arbitrage. These findings highlight the role of producers, hedge funds, and swap dealers in price formation processes in commodity futures—information that is beneficial to academics, practitioners, and regulators.     

Quantification of the high level of endogeneity and of structural regime shifts in commodity markets

We propose a “reflexivity” index that quantifies the relative importance of short-term endogeneity for several commodity futures markets (corn, oil, soybean, sugar, and wheat) and a benchmark equity futures market (E-mini S&P 500), from mid-2000s to October 2012. Our reflexivity index is defined as the average ratio of the number of price moves that are due to endogenous interactions to the total number of all price changes, which also include exogenous events. It is obtained by calibrating the Hawkes self-excited conditional Poisson model on time series of price changes. The Hawkes model accounts simultaneously for the co-existence and interplay between the exogenous impact of news and the endogenous mechanism by which past price changes may influence future price changes. Our robustness tests show that our index provides a ‘pure’ measure of endogeneity that is independent of the rate of activity, order size, volume or volatility. We find an overall increase of the reflexivity index since the mid-2000s to October 2012, which implies that at least 60–70 percent of commodity price changes are now due to self-generated activities rather than novel information, compared to 20–30 percent earlier. While our reflexivity index is defined on short-time windows (10–30 min) and thus does not capture long-term memory, we discover striking coincidence between its dynamics and that of the price hikes and abrupt falls that developed since 2006 and culminated in early 2009.     

Spot and Futures Prices and the Law of One Price

The law of one price (LOP) is tested for narrowly defined commodities traded in futures markets in different countries during the period 1973–80. Although the LOP holds as an average tendency for most of the commodities, there are instances of large riskless arbitrage returns (before transactions costs). Deviations from the LOP tend to be commodity specific rather than due to a common external factor and they tend to be smaller the longer the maturity of the futures contract.     

International shocks and growth in emerging markets

The paper provides evidence on the extent and channels of transmission of international shocks on the economic growth of emerging markets. Using a block dynamic factor model, the shocks are decomposed into four components; a general global component, an activity based component, a financial component and a commodity price component. Using a sample of 75 emerging markets over the period 1992–2009, the paper finds that the average effect of international shocks on emerging markets' growth over the entire sample period is negligible, which supports the classic view of isolated, de-coupled emerging markets. However, there is considerable variation both over time, over cross-section and across factors. When we split our sample by time period, we find greater effect of the international factors on the emerging markets' growth during 2002–2009 period. There is evidence which suggests that sensitivity to international shocks has increased over time and at the country level these sensitivities are more pronounced. Although the drivers of integration vary as does the sensitivity to alternative sources of shocks, we find that certain emerging markets have become considerably more integrated with the global economy than others. Overall, there is evidence of a significant impact on the economic growth of some emerging markets of the international shock caused by the global financial crisis.     

GAMBLING, SPECULATION, AND INSURANCE: WHY THEY CONTINUE TO BE CONFUSED AND CONDEMNED

Governments and the media have often attacked financiers for “speculating” in their countries' currencies, thereby forcing them to make drastic and sometimes painful changes in monetary and fiscal policies. This article argues that such accusations have no basis in economic theory, and that “such rhetoric should be seen for what it is: an attempt by politicians and policy-makers to divert attention and blame from their own mismanagement.” More generally, the author argues that the failure of the general public to understand the social benefits of financial activies such as trading in government bonds, commodity futures, and, more recently, financial derivatives has led throughout history to “prejudice, bad laws, and bad regulations.” Much as the charging of interest and certain forms of insurance were proscribed by the medieval Church, agricultural commodity futures were attacked in the 19th century (and in much of the 20th as well) in the U.S. and elsewhere as thinly disguised forms of gambling. Moreover, the same restrictions that were imposed on gambling and futures markets during the 19th and early 20th centuries are now imposed in many Third-World countries. Instead of encouraging the use of forward markets by small producers and traders, and promoting the development of organized commodity markets and banks in local centers, most less-developed countries today support national and international “stabilization” measures such as buffer stocks and regulations like price floors, price ceilings, and crop quotas. Meanwhile, in Western nations, governments continue to accuse financial markets of “destabilizing speculation” and of a myopic obsession with short-term profitability—even as the U.S. IPO market continues to assign record values to companies that have yet to show profits. Viewed in this light, the media and regulatory assaults on the junk bond markets in the late 1980s and on derivatives in the early 1990s are only the latest in a long line of misguided attacks on financial innovation.     

Do commodity markets catch a cold from stock markets? Modelling uncertainty spillovers using Google search trends and wavelet coherence

We investigate stock market uncertainty spillovers to commodity markets using wavelet coherence and a general stock market-related Google search trends (GST)-based index to proxy for uncertainty. GST reflect stock market uncertainty over short-, medium- and long-term horizons. Periods of association between GST and the VIX, a widely used proxy for stock market uncertainty, coincide with economic, financial, and geopolitical events. The association between the VIX and GST has grown over time. In line with economic psychology, this implies that during times of heightened uncertainty investors increasingly search for stock market-related information. Our analysis further reveals that some commodities are more susceptible to uncertainty spillovers from stock markets, notably energy commodities. We demonstrate how GST may be used to isolate the impact of specific events and show that COVID-19 had a disproportionate impact on commodity price volatility. We also find that energy, livestock and precious metals are increasingly integrated with stock markets. Spillover analysis repeated using the VIX produces similar results and reflects information that is also reflected in GST, confirming an uncertainty narrative. The use of wavelet analysis and GST to proxy for general and event specific uncertainty offers an alternative perspective to traditional econometric approaches and may be of interest to econometricians, analysts, investors and researchers.     

Time-variations in commodity price jumps

In this paper, we study jumps in commodity prices. Unlike assumed in existing models of commodity price dynamics, a simple analysis of the data reveals that the probability of tail events is not constant but depends on the time of the year, i.e. exhibits seasonality. We propose a stochastic volatility jump–diffusion model to capture this seasonal variation. Applying the Markov Chain Monte Carlo (MCMC) methodology, we estimate our model using 20 years of futures data from four different commodity markets. We find strong statistical evidence to suggest that our model with seasonal jump intensity outperforms models featuring a constant jump intensity. To demonstrate the practical relevance of our findings, we show that our model typically improves Value-at-Risk (VaR) forecasts.     

Option-implied expectations in commodity markets and monetary policy

In this paper we estimate the dynamic interactions between option-implied variance and skewness in agricultural commodity markets and monetary policy. Using a structural vector autoregressive (SVAR) framework, we find that an expansionary (contractionary) monetary policy upwardly (downwardly) revises commodity markets’ expectations about the price and volatility path of agricultural products. On the other hand, our empirical analysis reveals that monetary policy does not have a systematic and timely response to sudden changes in option implied expectations of commodity investors. In addition, we provide empirical evidence showing the robust forecasting power of agricultural option-implied information on monetary policy with R² values reaching almost 52%.     

Consequences of asset shortages in emerging markets

We assess econometrically the impact of asset shortages on economic growth, asset bubbles, the probability of a crisis, and the current account for a group of 41 emerging markets (EMs) for 1995–2008. The econometric estimations confirm that asset shortages pose a serious danger to EMs in terms of reducing economic growth, raising the probability of a crisis, and leading to asset price bubbles. Moreover, asset shortages can also explain the current account positions of EMs. The findings suggest that the consequences of asset shortages for macroeconomic stability are significant, and must be tackled urgently. We conclude with policy implications.     

Financialization and de-financialization of commodity futures: A quantile regression approach

This study employs a quantile regression approach to examine the financialization of commodity futures. We confirm a strong degree of dependence in energy commodities from 2004 to 2013, with moderate effects in metals and lesser magnitudes in agriculture. Our findings show a strengthening in the financialization of energy commodities during the 2008–2009 global financial crisis, while there were weaker effects in agriculture and a decoupling or de-financialization in metal markets. The findings reveal the de-financialization of metals and agricultural markets from 2014 to 2017, after the 2013 closure of commodity trading units on Wall Street. Overall, our findings cast doubt on the diversification benefits of energy-dominated commodity indices after 2013. We argue the impact of financialization on commodity futures markets is more permanent than previously thought.     

An analysis of time-varying commodity market price discovery

We propose a model of time-varying price discovery based on a rolling-window error correction framework. We show that price discovery in nine commodities is dominated by the spot market, while, in only six commodities, price discovery is dominated by the futures market. Our findings, therefore, challenge the well-established view in commodity markets that it is the futures market which dominates the price discovery process. We also show the economic significance of price discovery through a portfolio construction and hedging strategy.     

Informational Frictions and Commodity Markets

This paper develops a model with a tractable log‐linear equilibrium to analyze the effects of informational frictions in commodity markets. By aggregating dispersed information about the strength of the global economy among goods producers whose production has complementarity, commodity prices serve as price signals to guide producers' production decisions and commodity demand. Our model highlights important feedback effects of informational noise originating from supply shocks and futures market trading on commodity demand and spot prices. Our analysis illustrates the weakness common in empirical studies on commodity markets of assuming that different types of shocks are publicly observable to market participants.