As AQ pointed out this morning, today's slightly downward trend in MBS price began in the final hours of Friday's trading.  Both MBS and Treasuries put in their best marks of the day just before 2pm, and have moved steadily downward ever since.

You may notice, however, that both markets appear to be losing that negative steam near current levels.  For Treasuries, that looks to be around 3.60 and for MBS, around 101-08.  At the moment, the Fannie 4.5 is a tick higher than that at 101-09, but is still 5 ticks lower from Friday's closing prices.

All that being said, the more important trends to watch pertain to the generally supportive range for MBS that emerged even before Friday's boomy rally. 

AQ pointed this out as well, and it remains pertinent at the moment.  You can see on Thursday, after breaking the 101-06 level, prices returned for a test and were met with support.  Then on Friday, factoring out the immediate volatility from NFP, that same 101-06 level is the first real pivot point of the morning, in the sense that it was the first potential resistance from the oversold volatility early, and acted as support immediately thereafter.  Since we're so close to the mark right now, and since it suggests itself as one of the more important levels of late, I couldn't think of a better price to watch as a good barometer of potential lender rate sheet changes.

In other words, if we go much lower, we'll be letting you know that potential reprices are on the way.  Stay tuned.