With the number of exchange-traded funds growing like corn in July, it shouldn't be surprising that ETFs have been created that invest in... well... corn.

Actually, if you run into one of those extremely rare people with few complaints about the current upward spiral in food prices, it might very well be an owner of an agricultural ETF.

These six funds, for accuracy's sake, are technically exchange traded notes -- "ETNs" -- a subspecies of ETFs whose portfolio underpinnings are secured notes rather than portfolios of individual securities. And there's not a bad performance to be found among them.

With the total-return S&P 500 down by a double-digit percentage at midyear, investors might be delighted to end the year with a gain of more than 10% for 2008 -- while owners of the six agricultural ETFs all enjoyed advances of more than 10% in the month of June alone.

Each of the six agricultural commodity funds on the list was ahead by at least 11% for the year to date, with the iPath DJ AIG Grains Total Return ETN ( JJG) enriching its holders by 25.24% for the first half of the year.

Joining JJG with returns exceeding 17% for the month of June is another ag fund specializing in grains, the ELEMENTS MLCX Grains Index Total Return ETN ( GRU), up 17.10% for the month. It's linked to an index of futures contracts on corn, soybeans, soy meals and wheat. The third 17-percenter for June in the table, the Opta LB Commodity Index Pure Beta ETN ( EOH) focuses on grains and "soft sector" commodities, which normally include cocoa, sugar and coffee. EOH appreciated 17.12% in June.

The list includes three broad-based agricultural commodity funds that achieved gains in the 10%-15% range during June. The ELEMENTS RIC Index Agriculture Total Return Trust ( RJA) tracks a gauge representing a basket of futures contracts on 20 agricultural commodities. It gained 10.46% during the month.

The iPath DJ AIG Agriculture Total Return Sub-Index ETN ( JJA), which is linked to futures contracts of seven agricultural commodities, climbed 14.96% in June. And the PowerShares DB Agriculture Fund ( DBA), which is indexed to corn, wheat, soybeans and sugar, advanced 15.08% during the month.

Initially offered on Jan. 5, 2007, DBA is the senior fund on the list. RJA, JJA and JJG were all born in October of last year, while GRU and EOH debuted this past February.

A commodities fund, such as any member of the adjoining list, has an advantage of normally not being correlated with the stock or bond markets. Therefore -- as been happening this year -- they offer an investor who combines them with equity and fixed income holdings the possibility of some investments advancing during periods when others decline, thus "smoothing out" movements in the diversified portfolio.

Commodity investments also hold the promise of hedging against inflation.

But global commodity prices are notoriously volatile. The direction of prices can experience sudden and dramatic reversals. So while agricultural commodity funds look attractive during the current period of rising worldwide food prices, they could just as easily experience painfully long stretches as drags on overall portfolio returns.
ELEMENTS MLCX Grains Idx Tot Return (GRU) U 17.10 11.61 N/A 0.75 MLCX Grains Index
ELEMENTS RIC Index Agri Total Ret (RJA) U 10.46 9.42 11.16 0.75 Rogers International Commodity Index Agriculture Total Return
iPath DJ AIG Agri Tot Ret Sub (JJA) U 14.96 15.78 18.84 0.75 Dow Jones AIG Agriculture Total Return Sub Index
iPath DJ AIG Grains Tot Ret (JJG) U 17.09 20.19 25.44 0.75 Dow Jones AIG Grains Total Return Sub Index
Opta LB Cmdty Indx Pure Beta Agri (EOH) U 17.12 25.24 N/A 0.85 Lehman Brothers Commodity Pure Beta Agriculture Total Return Index
PowerShares DB Agriculture Fund (DBA) A+ 15.08 11.61 23.31 0.75 Deutsche Bank Liquid Commodity Index Optimum Yield Agriculture Excess Return
S&P 500 Total Return Index -8.35 -2.53 -11.60
Data as of 6/30/2008.
Source: TheStreet.com Ratings & Bloomberg

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Richard Widows is a senior financial analyst for TheStreet.com Ratings. Prior to joining TheStreet.com, Widows was senior product manager for quantitative analytics at Thomson Financial. After receiving an M.B.A. from Santa Clara University in California, his career included development of investment information systems at data firms, including the Lipper division of Reuters. His international experience includes assignments in the U.K. and East Asia.