Investors buy and sell commodities through either futures contracts on an exchange, or forward contracts over-the-counter. This effectively means that prices are agreed upon months in advance, and these exchanges standardise the quantity and minimum quality of the commodity. For example, the London Commodity Exchange might stipulate that 5,000 bushels comprise one wheat contract. It would also state which grades of wheat could be used to satisfy the contract. All wheat that meets that grade and criteria will be sold for the same price, regardless of where it was grown, and any slight variations in quality.
In the physical commodities market, there will be an actual exchange of goods. A breakfast cereal producer might also buy a futures contract for corn with a delivery date months in the future. This way, buying under a futures contract will protect the buyer if the future market price of corn is higher than the agreed price. The certainty that the transaction will take place allows both parties to plan and budget confidently.
Most commodity traders, however, do not take physical ownership of the goods. Commodity speculators or traders take a financial position (long or short) on a commodity. Commodities can as contracts for difference (CFDs) can be done using an online trading platform.
Learn how to trade commodities.