http://seekingalpha.com/author/mark-anth...

..... believe that pure computer trading is the wrong way to invest in commodities. To invest in commodities you HAVE to get your hands dirty and lay your hands on the physical things. Let me explain using the example of the United States Natural Gas (UNG) fund.

Recent dismay performance of UNG gave me pause to think about how to invest in commodities. Natural gas spot price recovered from the low of about $1.84 to now nearly $5, almost a triple, but the share price of UNG still struggles around $10. Why is UNG not tracking the price of the natural gas itself? The simple answer is it's killed by contango. But there is a deeper reason.

UNG does not hold the physical natural gas. Instead they hold futures contracts. In theory, when natural gas price goes up, the asset value of these futures contract also go up. But in reality such methodology is flawed. You are holding future contracts that you never intend to take delivery. So near the expiration of the future contracts, you are forced to sell them, at any low price. Mean while you must buy the next month's future contracts, at whatever high price they are offered. As a result, in each round of the roll-over, UNG loses positions and loses money.

More over, the more investors are interested in UNG, the worse a situation UNG finds itself in. (Remember, the bigger crowd is always the loser!!!) During each roll-over, UNG could be purchasing more future contracts than producers have products available to write those contracts, hence it bids up price on the buying end. Then it turn around to sell the future contracts to industry consumers, it has more to sell than the industry consumers can buy, hence it pushes the price down on the selling end. How could you not lose money? It's like two mechants compete with each other. They bid the price up purchasing produces from the same farm, and then cut each other's throat to sell to customers at super low prices. Both lose.

Since UNG purchases future contracts that it never intend to take delivery, conceiveably on the other end of trade could be some one who write future contracts that he never intended to deliver, as he does not have the product to deliver. As no delivery is ever demanded, such paper future contracts can be created out of thing air in unlimited quantity to "meet" investment demand. Basically one side provides empty promises of supply, the other side provides false demand that never materializes. This is nothing but a zero sum game. One party's loss is exactly the other party's gain.

Therefore it is flawed to believe that trading future contracts is investing in cmmodities. It is NOT. Future contracts are derivatives with which the two sides gamble against each other. The commodity may be bullish, but you have a 50/50 chance to beat your counter party to win.

If you are interested in commodity investment, do NOT buy paper derivatives, whose supply is unlimited. Buy the physical thing, which is limited, and take delivery.