Commodity market in Sumer between 4500 BC and 4000 BC. Sumerians first used clay tokens sealed in a clay vessel, then clay writing tablets to represent the amount—for example, the number of goats, to be delivered. These promises of time and date of delivery resemble futures contract. Early civilizations variously used pigs, rare seashells, or other items as commodity money. Since that time traders have sought ways to simplify and standardize trade contracts. Gold and silver markets evolved in classical civilizations. At first the precious metals were valued for their beauty and intrinsic worth and were associated with royalty. In time, they
Commodity price index can be traded on an exchange in much the same way as stock index futures. Investors can choose to obtain a passive exposure to these commodity price indices through a total return swap or a commodity index fund. The advantages of a passive commodity index exposure include negative correlation with other asset classes such as equities and bonds, as well as protection against inflation. The disadvantages include a negative roll yield due to contango in certain commodities, although this can be reduced by active management techniques, such as reducing the weights of certain constituents (e.g. precious and base metals) in