— Investors holding more than 90 percent of the debt sign up: The offer and the bailout go ahead as planned. Greece now faces the challenge of implementing all the conditions attached to the rescue loans and slowly returning its battered economy back to growth.
Lewis of Monument Securities said a participation rate of more than 75 percent but less than 90 percent was most likely.
"Then it may get a bit messy," he said, since that would kick off another round of negotiations between Athens and the other eurozone countries.
AP Business Writer David McHugh in Frankfurt, Germany, contributed to this story.