Despite the stock rally and slightly higher treasury yields, MBS had advanced in a steady range into the afternoon.  As of about 2 minutes ago, we encountered a few ticks of selling.  This occurs just after the book close of the bond market which often leads to volatility in MBS as liquidity and participation start to dry up, especially on Friday afternoons.  As such, I'd read less into this bit of selling than normal.  But prices are prices and some lenders may react.