I´ve never actually heard it called that, except the OP using it. I don´t think we will ever see anything near 50%. Probably the worst that can happen is like 2008, but even that was a perfect storm. It is hard for the world to crash at the same time because everything that hurts someone, helps someone else so it would be easy to shift assets around. The more globalized markets become, the more resistant they are to drastic changes.