How commodity indices broke the wheat futures market
Back in March 2008, Diana Henriques noted something very odd: a large number of futures contracts traded in Chicago were expiring at levels much higher than the spot cash price. She said at the time that “economists who have been studying this phenomenon say they are at a loss to explain it”.
This very odd phenomenon — which caused farmers a lot of harm — has now been explained in a 247-page report from the Senate investigations subcommittee, entitled Excessive Speculation in the Wheat Market. The main PDF is here; there are exhibits and addenda here. The culprit, it turns out, is index traders.
The rise in the basis between the futures price and the cash price is a function of the rise of commodity indices, and investors buying a basket of commodities. This affected the wheat market particularly badly, as explained in footnote 213 of the report, partly because of the ease of storing wheat:
Aside from wheat, the other commodity markets in which index traders hold a substantial share of the long open interest are the futures markets for two livestock commodities, lean hogs and live cattle. Lean hog futures contracts are financially settled, meaning that the price of the expiring futures contract is set at the price of the commodity in the cash market at contract expiration. By definition, therefore, lean hog futures and cash prices will be equal at settlement, so there is no problem with convergence. Live cattle, unlike grain, cannot be placed in storage from one contract expiration to another. That constraint means there is always an active cash market for live cattle at contract expiration that helps to force convergence.
The Senate subcommittee recommends that the futures exchanges should curb speculation in the futures market in order to bring the basis between futures and cash back down to a reasonable level. It’s coming down already, but it’s still extremely high, at over a dollar a bushel:
This whole thing reminds me slightly of the way in which the USO oil ETF helped to exacerbate contango in the oil market. And in general, it seems that attempts by investors and banks to construct financial instruments which give simple exposure to commodities have not worked very well. Chalk up another failed financial innovation.