City officials say they are prepared to take charge of the Subte if the government pays 10% of its debt to Metrovias and lets the city raise the rest from the Inter-American Development Bank and the World Bank.

ECONOMIST: Mayor v president v commuters

As for Japan, KMV's model says that 3 of Japan's 19 largest banks -- it won't name names -- have at least a 2% chance of defaulting on their debt over the next year if the government lets market forces take their course.

FORBES: Default-risk bookies

Most of that is sold by bigger players, those that have the large amounts of bonds outstanding needed for the trading activity that lets investors assess the "fair value" of the debt.

WSJ: European Banks��Large and Small��Rely on ECB