Not All Commodity ETFs Are Created Equal [View article]
"Either oil is overpriced or natural gas is undervalued." This assumes a somewhat fixed offering and demand of oil to gas. Could be that all of a sudden more gas (or expectation thereof) is available (and gas got cheaper by more supply and same demand) and you now move from a 8.6 to 18.1 ratio.
Not All Commodity ETFs Are Created Equal [View article]