With crude oil prices down more than 50% since June its worth looking at what commodities are likely to be most affected by the slump and what's happened so far.
The relationship is complex though and it may be too early to draw any firm conclusions. Given that energy accounts for up to 50% of the production cost of many commodities, a drop in the oil price reduces the price floor. In the longer term though all commodities could see higher demand (and prices) if the drop in the oil price eventually stimulates an increase in economic growth
In terms of agricultural commodities corn is most directly affected by lower oil prices as lower energy costs reduce the cost of production, increase margins and encouraging more planting. Corn is also used in bio-ethanol and so lower corn prices could see higher demand.
However, Cotton has the largest per-acre energy costs of all agricultural commodities so it is likely to see the steepest falls. According to a recent report from Societe Generale the historical correlation between cotton and crude is the highest across all commodities at 0.45:1.
The impact on metals is more complex. According to Macquarie Aluminum production has the highest energy-related costs at around 40%, copper the lowest at 18% with gold coming in second last with 22% of production costs related to energy prices.
While electricity accounts for 40% of the production costs of aluminum, the most energy intensive of the base metals, thermal coal is the predominant power-source rather than crude. However, during periods when crude prices are driven to extreme highs or lows the relationship between crude and thermal coal become much closer potentially leading to a higher correlation between crude and aluminium prices.
Gold also has a complex relationship with crude. Lower oil prices, if reflected in a decline in fuel prices could increase consumer spending on gold jewelry, particularly in countries like India who stand to benefit greatly from lower crude prices. However investment demand for gold could decline if lower oil prices lead to lower inflation.
Macquarie note in recent year Platinum, Silver and aluminum have had the highest correlation with oil prices but over the longer term platinum, copper and tin had the highest correlation with oil prices with palladium the weakest correction.
Finally, the effect on natural gas prices is more direct, at least in the short term. With gas contracts linked to oil (particularly in Europe and Asia) a decline in the oil price will feed directly into gas prices. In the U.S. the decline in oil price could encourage shale drillers to use more gas rigs in preference over oil, increasing gas supplies and leading to a further drop in gas prices.
Of these commodities here’s what happened since crude began its plunge in mid-June – corn (down 12% ), cotton (21%), aluminium (unchanged), copper (down 7%), gold (down 8%) and US natural gas (down 37%). This would tend to support the previous analysis, particularly suggesting Natural Gas and cotton are the most vulnerable to the fall in crude prices. However, it will be sometime before the full effect is felt, particularly the timing and scale of any demand side impact.