In day-over-day terms, the 1-2bps gain in 10yr yields and the 3-5 ticks improvement in MBS prices don't seem overly impressive.  But if we consider that each of the past 3 days has seen 10yr yields close at the best levels of the month, it's a bit more interesting.  Bonds haven't ended a month with yields this low since April.

This wasn't necessarily a given from the outset today.  While stocks and bonds don't necessarily HAVE TO follow each other, they've been sticking pretty close during the month.  So there was some pressure from that "risk-on" trading stance (buy stocks, sell bonds) overnight.  Treasury yields rose consistently through both the Asian and European sessions, getting little help from a slightly weaker reading on Eurozone inflation. 

It wasn't until 8:20am that we saw buyers surface.  This is usually a dead giveaway, because nothing hugely important is ever scheduled at 8:20am apart from the CME open for Treasury derivatives.  When 8:20 results in a big move, it's a clear sign that trading positions are driving the movement (as opposed to markets reacting to fundamental data/events).  Today is one of the few days of the month where it's not quite so cut and dry because ADP Employment is released at 8:15am. 

In other words, there theoretically COULD have been some sort of delayed reaction to the ADP data, but if so, other markets really didn't seem to care much.  The bigger deal for bonds was the Chicago PMI data, which came in much weaker than expected.  It might have had more of an impact if not for the Employment component being strong--a fact that only matters because it's NFP week.