But despite popular belief, subprime mortgages with exotic features had little to do with the housing bubble and the current debt overload weighing down U.S. households.

Meanwhile, collateralised-debt obligations (CDOs), made up of clumps of those securities and laced with leverage, have become almost impossible to trade.

Theoretically, SND has more significant market discipline effect than other financial instruments due to its characteristics of unsecured position, juniority and longer maturity.