The Great Pyramid of Korea

This is the equivalent of using one credit card to pay off another credit card. Although remaining solvent, the BoK descends further into debt.
Such a scheme is also called a Ponzi scheme. Ponzi schemes eventually collapse leaving the last investors with huge losses. This is why Ponzi schemes are illegal. If any individual in Korea were to set up a similar scheme, they would be risking a prison sentence.

Source: Looming Disaster for the Bank of Korea - OhmyNews International