Fungibility Fungibility In economics, fungibility is the property of a good or a commodity whose individual units are essentially interchangeable. For example, since one kilogram of pure gold is equivalent to any other kilogram of pure gold, whether in the form of coins, ingots, or in other states, gold is fungible. Other fungible commodities include sweet crude oil, company shares, bonds, other precious metals, and currencies. Fungibility refers only to the equivalence of each unit of a commodity with other units of the same commodity and not to the exchange of one commodity for another, which is barter. The word "fungibility"
Commodity index fund Commodity index fund A commodity index fund is a fund whose assets are invested in financial instruments based on or linked to a commodity price index. In just about every case the index is in fact a commodity futures index. You cannot invest in an index, but you can invest in a fund. A Commodity Index Fund is a fund which either buys and sells futures to replicate the performance of the index, or sometimes enters into swaps with investment banks who themselves then trade the futures. The biggest and best known such fund is the Pimco Real Return Strategy