The US just passed its debt limit. If that limit isn't raised, the global economy could go into free-fall.

John Kunkel believes the likelihood of default is low but not not negligible. 

"I think in some quarters that the nature of the, the new Republican Congress has a particular tilt toward brinkmanship this time and add to that the fragility of the global economy. So I don't think you can be entirely relaxed about the situation at all."