These days, the Wall Street banks are more like those grain traders than you might think. They have equipped themselves to take delivery of raw materials when they choose to, so they can wait for the commodity price to rise without having to roll contracts, giving them another advantage over ETF investors. Goldman owns a global network of aluminum warehouses. Morgan Stanley chartered more tankers than Chevron last year, according to shipbroker Poten & Partners. And JPMorgan Chase hired a supertanker to store heating oil off Malta last year, likely earning returns of better than 50 percent in six months, says oil economist Philip Verleger.