Oil.

The Saudis are the monopoly provider of oil.  Every once in awhile we all need to be reminded of this simple fact.  And while coordination is possible with the Saudis and the U.S. with respect to the Russian problem, it is more likley that the Saudis have finally decided to demonstrate to shale producers and other would be competitors who is boss.  They lured out their competitors and are crushing them once they went all-in.

The junk world is shuddering with the prospect of $60 oil.