Rational Speculative Bubbles and Commodities Markets : Application of Duration Dependence Test

The presence of rational speculative bubbles in 28 commodities is investigated using the duration dependence test on the stochastic interest-adjusted basis. 11 of 28 commodities experienced some episodes of rational speculative bubble. These commodities are WTI crude oil, coffee, corn, soybean No. 2, soybean meal and oil, wheat No. 2 soft red and hard winter wheat, lean hogs, gold and platinum. Additionally, natural gas, propane, live cattle, and pork bellies exhibit mean-reversion in the interest-adjusted basis