Immovable object, meet irresistible force. Greek, eurozone and International Monetary Fund officials insist a Greek debt restructuring isn't an option; some European Central Bank figures even warn it poses a Lehman-style systemic threat. They argue they have a plan to repair Greek finances.

Markets don't believe them. Greek credit-default-swap prices imply a 46% probability of a restructuring over the next two years, according to Deutsche Bank. Yields on Greek bonds maturing in 2013 have skyrocketed to well over 20%.