During most of 2005-10, the price of expiring U.S. corn, soybeans, and wheat futures contracts settled much higher than corresponding delivery market cash prices. Because futures contracts at expiration are commonly thought to be equivalent to cash grain, this commodity price non-convergence...

In a well-functioning futures market, the futures price at expiration equals the price of the underlying asset. This condition failed to hold in grain markets for most of 2005-10. During this period, futures contracts expired up to 35% above the cash grain price. We develop a rational...