This paper evaluates how different types of speculation affect the volatility of commodities' futures prices. We adopt four indexes of speculation: Working's T, the market share of non-commercial traders, the percentage of net long speculators over total open interest in future markets, which...

We show that, since the inception of energy futures markets, prices have on average exhibited backwardation. Normal backwardation has also been the norm, but, because of the low power of the standard tests, most researchers have concluded that the unbiased expectations model cannot be rejected....