Futures prices increase and decrease largely because of the myriad factors that influence buyers’ and sellers’ judgments about what a particular commodity will be worth at a given time in the future (anywhere from less than a month to more than two years).
As new supply and demand developments occur and as new and more current information becomes available, these judgments are reassessed and the price of a particular futures contract may be bid upward or downward. The process of reassessment—of price discovery—is continuous.
Thus, in January, the price of a July futures contract would reflect the consensus of buyers’ and sellers’ opinions at that time as to what the value of a commodity or item will be when the contract expires in July. On any given day, with the arrival of new or more accurate information, the price of the July futures contract might increase or decrease in response to changing expectations.
Competitive price discovery is a major economic function—and, indeed, a major economic benefit—of futures trading. The trading floor of a futures exchange is where available information about the future value of a commodity or item is translated into the language of price. In summary, futures prices are an ever changing barometer of supply and demand and, in a dynamic market, the only certainty is that prices will change.