The "yes" vote by the International Swaps and Derivatives Association triggers roughly $3.2 billion in CDS, which are insurance policies that pay out if a bond issuer defaults. That amount is actually much smaller than many had feared.

The decision was widely expected, and stocks were slightly downafter the announcement.

Greece pushed through a bond swap dealon Friday, forcing bond holders to take a significant "haircut" on the return of their money. The swap was approved by about 84 percent of the holders, and Greece is moving to activate a rule forcing the rest of the bondholders to go along with the deal.

The triggering of that rule, known as the Collective Action Clause, is what prompted the ISDA to decide that Greece has created a "credit event."