MBS are now down 3 ticks on the day (.09) and nearly a quarter point from the AM highs.  Lenders are at risk of negative reprices.  

10yr yields are up 4.3bps at 4.577.  

The sell-off is not extending for now.  The catalyst is a verbiage change in the Fed announcement (minor, first paragraph).  The press conference is still the big potential market mover and this is just a bit of noise in advance.