Global stock market and sovereign default.

Sovereign defaults present serious risk for the stock market. Overall, stocks in
affected countries decline considerably, and the desease infects the rest of the
Globe. Here is a recent example, the currency crash in Iceland. While US is
much bigger, the problems in the US, the UK, and Southern Europe are all similar.
2008 proved that TBTF (too big to fail) do fail!

Be careful and prepared