A futures contract is a type of derivative instrument, or financial contract, in which two parties agree to transact a set of financial instruments or physical commodities for future delivery at a particular price. If you buy a futures contract, you are basically agreeing to buy something that a seller has not yet produced for a set price. But participating in the futures market does not necessarily mean that you will be responsible for receiving or delivering large inventories of physical commodities - remember, buyers and sellers in the futures market primarily enter into futures contracts to hedge risk or speculate rather than to exchange physical goods (which is the primary activity of the cash/spot market). That is why futures are used as financial instruments by not only producers and consumers but also speculators.
The players in the futures market fall into two categories: hedgers and speculators.
Farmers, manufacturers, importers and exporters can all be hedgers. A hedger buys or sells in the futures market to secure the future price of a commodity intended to be sold at a later date in the cash market. This helps protect against price risks.
The holders of the long position in futures contracts (the buyers of the commodity), are trying to secure as low a price as possible. The short holders of the contract (the sellers of the commodity) will want to secure as high a price as possible. The futures contract, however, provides a definite price certainty for both parties, which reduces the risks associated with price volatility. Hedging by means of futures contracts can also be used as a means to lock in an acceptable price margin between the cost of the raw material and the retail cost of the final product sold.
Other market participants, however, do not aim to minimize risk but rather to benefit from the inherently risky nature of the futures market. These are the speculators, and they aim to profit from the very price change that hedgers are protecting themselves against. Hedgers want to minimize their risk no matter what they're investing in, while speculators want to increase their risk and therefore maximize their profits.
In the futures market, a speculator buying a contract low in order to sell high in the future would most likely be buying that contract from a hedger selling a contract low in anticipation of declining prices in the future.
Unlike the hedger, the speculator does not actually seek to own the commodity in question. Rather, he or she will enter the market seeking profits by offsetting rising and declining prices through the buying and selling of contracts.