▁from ▁higher ▁prices . ▁ ▁More ▁supply ▁becomes ▁available ▁from ▁alternative ▁sources ▁previously ▁considered ▁une conom ic . ▁ ▁In ▁oil ▁mark ets , ▁qu ota ▁systems ▁that ▁attempt ▁to ▁control ▁supply ▁come ▁under ▁stra in ▁as ▁the ▁re wards ▁for ▁che ating ▁rise . ▁ ▁As ▁prices ▁rise , ▁the ▁demand ▁for ▁the ▁comm od ity ▁will ▁begin ▁to ▁fall ▁as ▁it ▁faces ▁competition ▁from ▁che aper ▁sources . ▁The ▁net ▁effect ▁is ▁to ▁keep ▁comm od ity ▁prices ▁bound ▁around ▁their ▁long ▁run ▁average ▁price . ▁ ▁In ▁ess ence ▁the ▁DB L CI - MR ▁is ▁a ▁strategy ▁to ▁buy ▁low ▁and ▁sell ▁high . ▁It ▁therefore ▁tends ▁to ▁take ▁prof its ▁gradually ▁in ▁a ▁b ull ▁run ▁and ▁re - in vest ▁those ▁proceed s ▁into ▁che aper ▁comm od ities . ▁One ▁benefit ▁of ▁this ▁approach ▁is ▁that ▁the ▁DB L CI - MR ▁tends ▁to ▁extract ▁vol at ility ▁from ▁the ▁index ▁since ▁as ▁comm od ity ▁prices ▁r ally ▁so ▁to ▁does ▁vol at ility . ▁evidence ▁suggests ▁that ▁port fol ios ▁compr ising ▁past ▁los ers ▁tend ▁to ▁out perform ▁past ▁w inners ▁and ▁vice ▁vers a ▁over ▁time , ▁see ▁H ers h ▁She fr in , ▁Bey ond ▁Gre ed ▁and ▁F ear , ▁Harvard ▁Business ▁School , ▁ 2 0 0 0 . ▁In ▁fact ▁this ▁has ▁been ▁a ▁rec urr ing ▁theme ▁of ▁comm od ity ▁mark ets ▁over ▁the ▁past ▁few ▁years . ▁We ▁find ▁that ▁it ▁has ▁been ▁common