Periodically, the global economy experiences great commodity booms and busts, characterized by a broad and sharp comovement of commodity prices. There have been two such episodes since the Korean War. The first event peaked in 1974 and the second in 2008, 34 years apart. Both created major...

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...