Dylan Thomas would have been shaking his head had he seen the bond market's inability to "rage against the dying of the light" today.

The 4.0 did get quite a nice bounce off the long term floor, but has since cut power to engines as it slowly descends back to those levels.  Graphically now:

Whereas this late day "leak-out" could perhaps pass for gentle, the utter submission and subsequent demolishing of treasuries was anything but.  Even though the late day price action in treasuries was also gentle, comparing the two days--MBS and Tsy's--The latter was more or less crushed by comparison, with spreads cinching tighter by anywhere from 4-8 basis points depending on your benchmark of choice.

The 10 yr yield has now backed up to an eye-watering 3.35%!  Yikes.  MBS still over the floor!  Looks to stay that way in the last hour.