Streetwise Professor

Tom Fowler of the Houston Chronicle quotes me in a blog post spurred by US Asst. Attorney Belinda Beek’s mentioning during jury selection in the manipulation trial of several former El Paso traders that onions were not covered by the Commodity Exchange Act. As I noted to Tom, onion futures were banned due to intense political pressure from onion farmers after several episodes in which the price of onion futures plummeted, at times falling below the price of the sacks in which they were shipped.

Interestingly, in 1972 similar events in the potato market led to the proposal of a bill to ban potato futures. This bill failed, however, in part because a USDA study of what happened in onions after futures trading was banned; the USDA study did not find any evidence that the ban had affected pricing patterns. In a 1963 article in the Journal of Farm Economics Roger Gray found that if anything, the ban increased volatility of onion prices.

The potato contract died a somewhat unnatural death a few years later due to several spectacular manipulation attempts, but this time Congress did not commit the murder. In one of these manipulations, in 1976, both a big long and a big short were trying to manipulate the contract simultaneously, with the short trying to ship huge quantities of potatoes from Idaho to Maine (the delivery point) and the long tied up most of the railroad cars on the Bangor & Aroostook Railroad (in which delivery had to be made). There was a large default against the futures contract. The default severely damaged NYMEX’s reputation. Here is a court case that provides some of the lurid details.

Ironically, the demises of the onion and potato contracts were perhaps the best things that happened to the CME and NYMEX, respectively. The loss of these contracts forced each exchange to innovate to find replacements. CME developed meat futures (including the legendary pork belly contract, which is now fading away but was once the hottest thing in town) to replace onions. NYMEX, under the leadership of Michael Marks, developed energy futures. (Which, funnily enough, a commenter on the Fowler post says should be banned. La plus ca change.) Necessity as the mother of invention, futures exchange edition.

The common feature of potatoes and onions is perishability. Perishability makes prices inherently volatile, and also can make some manipulative strategies possible. Indeed, short manipulations are likely to be more profitable for things like onions and potatoes than other products because dumping additional supplies on the market can depress prices sharply because the perishable good must be consumed almost immediately. This allows someone short futures to profit substantially.