In and of themselves, prices of front-month MBS (“front-month” meaning the most current delivery month, in this case, the December coupons that are currently in their settlement process for Fannie and Freddie 30yr’s) are doing amazingly well. But by the time prices seemingly drop to reflect January coupons (after the close tomorrow), we’d currently be looking at 102-05 on a Fannie 3.5 instead of the current 102-14.
Beyond that, buyers across the fixed-income world are lopsidedly outnumbering sellers, especially in MBS. Lenders aren’t in a big hurry to get any new locks in the door given the past several days of rallying and the fact that they’ve already originated quite a lot today of new MBS today given the gains. Not much incentive to lower rates when buyers are already lined up for MBS.
That said, some lenders might reprice, just don’t expect to see as many rate sheet improvements as you would outside of the MBS settlement cycle. The broader lopsided demand for fixed-income today merely compounds the issue.