Sovereign credit-default swaps have been used as a type of insurance against sovereign governments not paying back the money they owe. As with any insurance product, the more expensive it is, the more likely the event you're insuring against will happen soon.
http://uk.businessinsider.com/the-riskiest-sovereign-bonds-ranked-2015-8#ixzz3ioEzW7jm
http://uk.businessinsider.com/the-riskiest-sovereign-bonds-ranked-2015-8#ixzz3ioEzW7jm