Movements in countries’ exchange rates can substantially change the prices of goods faced by producers and consumers and thereby affect incentives to produce, consume, and trade goods. Exchange rate changes, however, might not be completely transmitted (passed through) to domestic prices....

In 2008, wheat futures prices spiked and then crashed along with prices for other agricultural and nonagricultural commodities. Market observers offered several theories to explain this common movement, or comovement, in prices, and have proposed policies to address the perceived problem of...