The Working Curve and Commodity Storage under Backwardation

There remains controversy over whether the empirical curve relating intertemporal commodity price spreads and stocks, originally drawn by Holbrook Working in 1933 (i.e., the Working curve), is a valid stylized fact in commodity markets. The core of the controversy is the portion of the curve representing commodity stocks under backwardation. In this article we analyze the original data used by Working, plus more disaggregated numbers. We find that the Working curve is indeed valid. The diversity of stockholders and different stockholding motives most likely explain the empirical Working curve relationship.     

High food commodity prices: will they stay? who will pay?

Much of the public discussion of the food price crisis has focused on the sharply increased use of food commodities for biofuel production, framing debate in simple food versus fuel terms. Reality is more complex. Multiple forces drove food prices to high levels and, according to findings we report in this article, these forces will sustain high prices over the medium term. We also find that the distinction between high world prices for food commodities and the consumer costs of food is an important one to make. Food consumers do not buy raw food commodities at international prices. The degree to which the price of traded food commodities and the price of food are related depends on a long list of factors, most of which operate to dampen price transmission. In the search for appropriate policy response, it is essential to measure consumer effects correctly and to apportion properly the causes of current high prices.     

The integration of energy and agricultural markets

This article addresses the evolving links between energy and agricultural markets. Prior to 2005, there was little correlation between energy and agricultural commodity prices. In 2006–2008, with the ethanol boom in the United States, there emerged a strong link between crude oil, gasoline, and corn prices. There was little link between ethanol and corn. However, in late 2008 and 2009, the markets changed as ethanol production came under severe economic pressure and 2 billion out of 12 billion gallons of capacity shut down. During this period ethanol became priced more on corn, as the breakeven corn price helped drive the ethanol market. This article explores the drivers in these markets as well as other major issues facing the corn ethanol industry in the United States such as the blend wall. The article concludes with a review of prospects of a future cellulosic biofuels industry.     

Monetary Impacts and Overshooting of Agricultural Prices in an Open Economy

This article's focus is on the time adjustment paths of the exchange rate and prices in response to unanticipated monetary shocks. First, we expand the theoretical specification of the overshooting hypothesis by generalizing Dornbusch's model to include a third sector (i.e., agricultural prices). Second, we employ Johansen's cointegration test along with a vector error correction model to investigate whether agricultural prices overshoot in an open economy. The empirical results indicate that agricultural prices adjust faster than industrial prices to innovations in the money supply, affecting relative prices in the short run, but strict long-run money neutrality does not hold.     

What Explains Agricultural Price Movements?

After 2005, commodity prices experienced their longest and broadest boom since World War II. Agricultural prices have now come down considerably since their 2011 peak, but are still 40% higher in real terms than their 2000 lows. This paper briefly addresses the main arguments on the causes of the agricultural price cycle. It broadens the scope of analysis by focusing on six agricultural commodities, and identifies the relative weights of key quantifiable drivers of their prices. It concludes that increases in real income negatively affect real agricultural prices, consistent with the Prebisch–Singer hypothesis and its predecessor, Engel's Law. Energy prices matter most (not surprisingly, given the energy‐intensive nature of agriculture), followed by stock‐to‐use ratios and, to a lesser extent, ex‐change rate movements. The cost of capital affects prices only marginally, probably because it not only influences demand, but also evokes a supply response. The added value of these results lies in that, when examined in tandem and against market fundamentals, they challenge the conclusions from uni‐dimensional approaches that often put disproportionate weight on an individual factor.     

Do Futures Benefit Farmers?

Simulations are used to analyze welfare and market- and farm-level effects of making futures available to producers of a storable commodity. Key features of the model are the explicit consideration of dynamic impacts due to inventories, and of aggregate market effects associated with futures adoption by some producers. Application to the natural rubber market shows that futures availability can lead to sizable market- and farm-level effects. Futures availability enhances consumer welfare, reduces nonadopter welfare, and yields important welfare gains for adopters when their market share is small and welfare losses when they account for a sufficiently large market share.     

On the Comovement of Commodity Prices

We present strong evidence against the excess-comovement hypothesis—that the prices of commodities move together beyond what can be explained by fundamentals. Prior studies employ broad macroeconomic indicators to explain common price movements, and potentially correlated fundamentals are not controlled for. We use inventory and harvest data to fit a partial equilibrium model that more effectively captures the variation in individual prices. The model explains the majority of the comovements among commodities with high price correlation, and all of the comovements among those with marginal price correlation. Common movements in supply factors appear to play an important role in the observed comovements in commodity prices.     

Consumer and Market Responses to Mad Cow Disease

We examine how consumers and financial markets in the United States reacted to two health warnings about mad cow disease: the first discovery of an infected cow in December 2003 and an Oprah Winfrey show that aired seven years earlier on the potentially harmful effects of mad cow disease. We find a pronounced and significant reduction in beef sales following the first discovery of an infected cow in a product-level scanner data set of a national grocery chain. Cattle futures show a pattern of abnormal price drops comparable to the scanner data. Contracts with longer maturity show smaller drops, suggesting that the market anticipated the impact to be transitory. Cattle futures show abnormal price drops after the Oprah Winfrey show that are more than 50% of the drop following the 2003 discovery of an infected cow.     

Commodity Prices and Unit Root Tests

Price theory suggests that commodity prices should be stationary series. Yet, tests for unit roots rather frequently imply that these prices are not stationary. This seeming inconsistency is investigated by applying alternative specifications of unit root tests to prices of corn, soybeans, barrows and gilts, and milk. The preponderance of evidence suggests that nominal prices do not have unit roots, but the results are sensitive to the specification of the test equation. Accounting for a structural change that shifts the mean appears to be an important issue in unit root tests.