Today is good one to speak about MBS and Treasuries separately, as they made fairly dissimilar moves.  On the Treasury front (which speaks more to the broader trends in interest rates), the day was a flat extension of Friday afternoon's flatness.  At the official 3pm close for Treasuries, they were almost perfectly unchanged.

MBS, on the other hand, have been in positive territory most of the day and are at their best levels heading into the 5pm close.  Fannie 4.0s gained the most--8/32nds (.25)--and 3.5s added 6/32nds.

Some of this outperformance could be due to a technical push back against underperformance in January.  While MBS have been generally strong against historical norms, Treasuries benefited more from the flight-to-safety rally that helped bond markets through the first week in February.  Now that stocks have stabilized and emerging markets aren't the drama du jour, some of that 'flight-to-safety' phenomenon is reversing.  

By the time we consider relatively light supply of MBS ahead of monthly settlement this week, we have plenty of justification for the home team to be winning this game.   Keep in mind that prices for Fannie and Freddie 30yr Fixed MBS will be dropping 8-12 ticks tomorrow due to "the roll."