Because Brent Crude is trapped in a triangle and volatility has compressed to a point from where it can only expand.
Here's Brent Crude Weekly Chart
In 2012, Brent Crude was trading in a big trading range b/w 90 and 125 but since then Brent Crude has witnessed compression in trading range. Now the range has become so tight - that a breakout (big move) is coming and the expectation is that move may be down. But one should wait for confirmation.
If Brent Crude breaks down, then it may head towards $90. Let us see what happens. It is a chart one should keep an eye on
The blogpost is purely for educational purpose.