Commodities are marketable items produced to satisfy wants or needs. Economic commodities comprise goods and services.
The Commission was established as an independent agency in 1974, assuming responsibilities that had previously belonged to the Department of Agriculture since the 1920s. The Commission historically has been charged by the CEA with regulatory authority over the commodity futures markets. These markets have existed since the 1860s, beginning with agricultural commodities such as wheat, corn, and cotton.
Over time, these commodity futures markets, known as designated contract markets (DCMs) regulated by the Commission, have grown to include those for energy and metals commodities such as crude oil, heating oil, gasoline, copper, gold, and silver. The agency now also oversees DCMs for financial products such as interest rates, stock indexes, and foreign currency.
Role in a portfolio
Commodity spot prices, as an asset class, do not generate a real return. Commodity mutual funds and ETF's invest in futures contracts that derive excess returns over the risk free rate of return from two sources:
- Changes in futures prices
- The roll yield—which can be either positive or negative—that results from replacing an expiring contract with a further out contract in order to avoid physical delivery yet maintain positions in the futures markets. 
Table 1. Commodity Index Returns 
(View Google Spreadsheet in browser, then File --> Download as to download the file.)
Open-ended mutual funds
- PIMCO CommodityRealReturn Strategy Fund Institutional (PCRIX) is an open-ended mutual fund which tracks Bloomberg Commodity Total Return Index[note 2] with collateral in inflation-indexed bonds. Expense Ratio 0.79%. Available at Vanguard Brokerage Service for $25,000 initial investment and a transaction fee.
- PowerShares DB Commodity Index Tracking Fund (DBC) is an Exchange Traded Fund which tracks the Deutsche Bank Liquid Commodity Index - Optimum Yield Excess Return. The Index is a rules-based index composed of futures contracts on six of the most heavily-traded and important physical commodities in the world - crude oil, heating oil, gold, aluminum, corn and wheat. Expense Ratio 0.83%.
- iShares S&P GSCI Commodity-Indexed Trust (GSG) is an Exchange Traded Fund which tracks the S&P GSCI Total Return Index. Expense Ratio 0.75%.
- iPath Dow Jones–UBS Commodity Total Return Index ETN (DJP) is an Exchange Traded Note which tracks Dow Jones–UBS Commodity Total Return Index. The note is issued by Barclays Bank PLC. Expense Ratio 0.75%.
- ELEMENTS RICI-Total Return (RJI) is an Exchange Traded Note which tracks the Rogers International Commodity Index - Total Return. The index is composed of futures contracts of 36 different commodities and is weighted based on global commodity consumption. The note is issued by the Swedish Export Credit Corporation. Expense Ratio 0.75%.
- A commodity is defined as:
See: CFTC Glossary
(1) A commodity, as defined in the Commodity Exchange Act, includes the agricultural commodities enumerated in Section 1a(9) of the Commodity Exchange Act, 7 USC 1a(9), and all other goods and articles, except onions as provided in Public Law 85-839 (7 USC 13-1), a 1958 law that banned futures trading in onions, and all services, rights, and interests in which contracts for future delivery are presently or in the future dealt in; (2) A physical commodity such as an agricultural product or a natural resource as opposed to a financial instrument such as a currency or interest rate.
- Bloomberg took over the maintenance of the Dow Jones-UBS Commodity Index on July 1, 2014. See Bloomberg Indexes to Oversee Leading Global Commodity Indexes.
- Commodity, on Wikipedia.
- Learning Resources - CFTC
- Putting Momentum into Commodities, by Paul D. Kaplan, Morningstar, 10/14/2011
- Data sources
Commodities Periodic Returns Table 2006-2010[dead link], Bloomberg Commodity Index (BCOM) 2014 and later.
Dow Jones Commodity Index factsheets
iShares S&P GSCI(R)Commodities Index ETF
- On Stuff by William J. Bernstein, 09/2006
- Siegel, Jeremy (May 19, 2006). "Commodities: Boom or Bust?". Yahoo Finance. http://www.jeremysiegel.com/index.cfm/fuseaction/Resources.ViewResource/type/article/resourceID/6601.cfm.
- Robert Greer Discusses the Benefits of Commodity Investing by Robert J. Greer, 03/01/2004
- What the Price of Gold Is Telling Us by Congressman Ron Paul, 04/25/2006
- Going Long on Commodities: Six ways to invest in commodities by Will Acworth, 05/15/2005
- A Rediscovered Asset Class: Commodity Futures by raddr, 02/04/2006
- Commodities As An Asset Class by Frank Armstrong, CFP, AIF, 07/15/2004
- Not All Commodity Indexes Are Created Equal (Part One of a Two Part Series) by Richard Feldman, CFP, MBA, AIF, 06/02/2006
- Are Commodities Futures Too Risky for Your Portfolio? Hogwash! by Knowledge@Wharton, 04/05/2006
- Contango, backwardation, and all that good stuff by Prof. James Hamilton, 06/12/2005
- CRB Indexes by CRB