These charts show the extreme volatility in the yield on 30-yr Treasuries in the past several years (below) and days (top). Since Oct. 4th, long-term T-bond yields have risen from 2.7% to 3.1%, a rather extraordinary move that has slashed the price of the long bond by almost 8% from last week's high. (How's that for a risk-free investment?) It's looking a lot like we have seen a major reversal of the panic that last week drove yields down to levels that implied the onset of a global recession/depression. Yields are still very, very low, however, and still priced to very dire assumptions about the U.S. economy's ability to grow. But T-bonds are far from being safe investments, even with the approach of Operation Twist. In the end, it's all about Europe and whether Europe goes down the drain and drags everyone with it. If Europe just manages to survive, long-term bond yields have plenty of room to rise, and prices to fall.
Source: Beware The Safety Of Treasuries