MBS and Treasuries are at slightly stronger levels compared to this morning. European markets are still pushing the pace to a large extent with stocks sliding on on Ukraine headlines and Bunds (10yr German debt) improving. Shifting momentum for the S&P at 9:50am coincided with a similar shift for Treasuries (from higher to lower yields).
All that having been said, the market sectors providing the guidance for domestic bond markets are moving much more than bond markets themselves. For the 10pt slide seen in S&P, Treasury yields only dropped 2bps (currently down only 1.1bps on the day at 2.781).
Fannie 4.0s are up 3 ticks on the day but only 2 of them since the earliest rate sheets. That means positive reprice risk is not on the radar except for those less common cases where lenders are simply looking for a certain amount of stability after having priced relatively conservatively right out of the gate.