Both Tsy's and MBS have fallen to the lows of the day, with MBS performing significantly better.
Things have gotten a bit ugly as evidenced by this not so friendly chart, showing 4.0's at 99-27.
Reprices for the worse are a distinct possibility depending on how hedged lenders were with their morning rate sheets.
Update 1: 11:45 AM
About 20 minutes after the sell off, we're rallying in a meaningful way. Less "telling," more "showing." Here ya go: