Bonds have been sliding into weaker territory after the 3pm CME close with 10yr yields up 3.8bps at 4.12 and MBS down 6 ticks (.19) on the day. 

Any lender that priced before 10:15am is seeing at least an eighth of a point of weakness in 5.0 coupons.  This is enough for some of the jumpier lenders to consider negative reprices.