The four countries that have high levels of debt relative to GDP (more than the 60% allowed by the Maastricht Treaty clause) are Portugal, Ireland, Greece, and Spain (hence, the nickname PIGS). As...

The four countries that have high levels of debt relative to GDP (more than the 60% allowed by the Maastricht Treaty clause) are Portugal, Ireland, Greece, and Spain (hence, the nickname PIGS). As deficits continued to be very high in these countries over the last decade or so, investors lost confidence in these countries and credit markets suddenly realized that their debt levels (and trends) were unsustainable.