Oil just made a huge move, and nobody noticed

The markets have been preoccupied with a flurry of political headlines over the past few months such as the Brexit and the US presidential election.
But in the background of all this, there has been a stealth slump in crude-oil prices.
Both front-month West Texas Intermediate crude and Brent crude prices have fallen by over 20% since their respective early-June peaks of $51.23 a barrel and $52.51 a barrel.
A drop of over 20% is considered to be a bear market.
A few months ago, analysts attribute