Much of the tumble has been attributed to a glut in supply, fueled largely by the boom in shale production in the US.
However, Deutsche Bank's Gaël Gunubu notes that an oversupply of oil doesn't sufficiently explain the fact that numerous other commodities have been tumbling.
Here's more from Gunubu:
"Traders were too busy selling to ask questions after the OPEC meeting yesterday. But the obvious one to ask is why are oil prices falling? If a shale driven supply glut is to blame then other commodities should be unaffected. However, oil's four-year low is mirrored by iron ore, cotton, gold and copper's monthly average price. Lower demand from weak economies could explain this pervasive slump across different commodities..."
Indeed, deteriorating demand can't be ignored. Back in October, the International Energy Agency said that in 2015, global oil demand growth will be weaker than previously forecast.
"Crude oil production has increased by only about 1 million barrels/day from 2012/10 level to today," tweeted Westwood Capital's Dan Alpert regarding US production. "The increased quantities presently at issue are not material enough to crash oil if global demand was healthy."
Below are charts for oil, iron ore, cotton, gold and copper.
And here are multi-year charts for the major commodities Gunubu mentions.
Iron ore, which is usually in huge demand from China, has tanked because of a slowdown in Chinese production.
And here's the multi-year chart for cotton:
And gold:
And copper:
