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 commodity funds

The performance of managed commodity fund investments during the years l982 through 1996 is examined, both as stand-alone investments and as assets in diversified stock and bond portfolios. Nine stylized commodity fund investments are examined: randomly-selected, single-CTAs, pool, and fund portfolios; equally weighted market portfolios (EWMPs) of CTAs, pools, and funds; and value-weighted portfolios (VWMP) of CTAs, pools, and funds. Further, two subperiods are examined: 1982–1988 and 1989–1996. Based on an analysis using Sharpe ratios as the performance criterion, several types of managed commodity funds make both good stand-alone investments and good portfolio assets; an EWMP of CTAs and a VWMP of pools receive the highest ranking among the alternative commodity fund investments. It is also shown that commodity indexes are not a substitute for a managed commodity fund investment. A number of issues warrant further study: Can investors still earn consistently attractive risk-adjusted returns on managed commodity fund investments if they do not hold diversified portfolios of CTAs and pools? Also: How can such high speculative returns be earned in efficient commodity markets? And: Are CTA and pool returns high because commodity fund managers have superior trading skill? An important issue for future research is to determine whether in fact CTAs do possess such skill. © 1999 John Wiley & Sons, Inc. Jrl Fut Mark 19: 377–411, 1999     

Approximation for convenience yield in commodity futures pricing

The pricing of commodity futures contracts is important both for professionals and academics. It is often argued that futures prices include a convenience yield, and this article uses a simple trading strategy to approximate the impact of convenience yields. The approximation requires only three variables—underlying asset price volatility, futures contract price volatility, and the futures contract time to maturity. The approximation is tested using spot and futures prices from the London Metals Exchange contracts for copper, lead, and zinc with quarterly observations drawn from a 25‐year period from 1975 to 2000. Matching Euro‐Market interest rates are used to estimate the risk‐free rate. The convenience yield approximation is both statistically and economically important in explaining variation between the futures price and the spot price after adjustment for interest rates. © 2002 Wiley Periodicals, Inc. Jrl Fut Mark 22:1005–1017, 2002     

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     

Time-series momentum in China's commodity futures market

This study examines the time-series momentum in China's commodity futures market. We find that a time-series momentum strategy outperforms classical passive long and cross-sectional momentum strategies in terms of the Sharpe ratio, risk-adjusted excess returns, and cumulative returns. The time-series momentum strategy with a 1-month look-back period and a 1-month holding period exhibits the best performance. We observe clear time-series momentum patterns and find that the time-series momentum strategy is effective in the Chinese commodity futures market. However, the momentum lasts for less time in China than in the United States because China's futures market seems to have a greater number of speculative investors.     

Intermediary asset pricing in commodity futures returns

This paper assesses the extent to which intermediary capital (IC) risk contributes toward explaining commodity futures returns. We find that the IC effect is substantially positive and continues to grow as the financialization of commodities deepens. Positive and negative IC risks play asymmetric roles, with the effect of negative IC strengthening in recent subperiods. We further confirm the heterogeneous roles of IC across individual commodities by cross-section analyses. Overall, the effect of the positive IC risk factor varies significantly. Portfolios with low basis, low open interest, low momentum, and low liquidity earn significantly higher returns than counterparty portfolios.     

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 relative efficiency of commodity futures markets

The ability of futures markets to predict subsequent spot prices has been a controversial topic for a number of years. Empirical evidence to date is mixed; for any given market, some studies find evidence of efficiency, others of inefficiency. In part, these apparently conflicting findings reflect differences in the time periods analyzed and the methods chosen for testing. A limitation of existing tests is the classification of markets as either efficient or inefficient with no assessment of the degree to which efficiency is present. This article presents tests for unbiasedness and efficiency across a range of commodity and financial futures markets, using a cointegration methodology, and develops a measure of relative efficiency. In general, the findings suggest that spot and futures prices are cointegrated with a slope coefficient that is close to unity, so that the postulated long-run relationship is accepted. However, there is evidence that the long-run relationship does not hold in the short run; specifically, changes in the spot price are explained by lagged differences in spot and futures prices as well as by the basis. This suggests that market inefficiencies exist in the sense that past information can be used by agents to predict spot price movements. A measure of the relative degree of inefficiency (based on forecast error variances) is then used to compare the performance of different markets. © 1999 John Wiley & Sons, Inc. Jrl Fut Mark 19: 413–432, 1999     

Time series volatility of commodity futures prices

This article examines the pattern of volatility over time of a series of commodity futures prices, and focuses in particular on the futures price variability as the maturity date of the futures contract approaches. In a rational expectations model of asymmetric information, the article provides conditions under which the Samuelson hypothesis—that the variability of futures prices increases as maturity approaches—will be true. © 2000 John Wiley & Sons, Inc. Jrl Fut Mark 20: 127–144, 2000     

The untold story of commodity futures in China

We investigate the behavior of commodity futures risk premia in China. In the presence of retail-dominance and barriers-to-entry, the term structure and momentum premia remain persistent, whereas hedging pressure, skewness, volatility, and liquidity premia are distorted by time-varying margins and strict position limits. Furthermore, open interest, currency, and inflation premia are sensitive to institutional settings. The observed premia cannot be attributed to common risks, sentiment, transactions costs, or data-snooping, but are related to liquidity, anchoring, and regulation-induced limits-to-arbitrage. We highlight the distinctive features of Chinese futures markets and assess the challenges posed to theories of commodity risk premia.