Reply #7: If there is fear of a default or if one occurs, the price of existing Treasury bonds will be bid...

[A HERETIC I AM]

down. Since yield and the price of a bond move inversely, yields will rise as prices fall. The way to profit from this is to sell short Treasury bonds, basically selling what you currently do not own, only to buy them later at a lower price and pocketing the difference.

There are Exchange Traded Funds that do this for you, though they are extremely risky, as they tend to be geared to produce results on the daily changes, as opposed to the long term trend.