After an initial euphoric response to QE4, bonds are pulling back a bit. 

"A bit" in this context is half of the move and that was a pretty big move.  2.5 UMBS are still up about a quarter point on the day, but they're nearly a point lower from the afternoon highs.  This is one of the few times you'll ever see MBS fall a point and potentially NOT see a negative reprice.

That said, negative reprices can't be ruled out from a few of the more reactive lenders.  Counterpoint: some lenders may still be repricing for the better and just a bit late to the party.

10yr yields are reapproaching their highs of the day, but still down 8bps at .798%