Fannie 3.0 MBS are now down an eighth of a point from the morning's highs, and currently at the weakest levels of the day.  As such, some of the jumpiest lenders may consider a negative reprice. 

10yr yields are up 4bps on the day at 1.794%.  

The most recent weakness seen in the past half hour is NOT lining up with European markets in any striking way.  If anything, bond yields are tracking better with stocks.  

In the bigger picture, however, overnight weakness can definitely be traced to the weekend's Brexit-related developments.