Since at least the middle of 2017, the Consumer Price Index has been in the driver's seat as far as economic data that matters to bonds.  This likely has to do with the fact that inflation looked like it had finally achieved its 2% target in a sustainable way. 

In fact, from late 2015 through March of 2017, core year-over-year CPI was over 2% and hit 2.3% on several occasions.  Then in the spring of 2017, it began declining and reported at 1.5% several times before being revised up to a floor of 1.7%.

In a real way, it was this inexplicable drop in inflation that helped bonds have a much better 2017 than it looked like they would have coming into the year.  Yields remained lower than expected as long as inflation remained lower than expected.  That's not to say it's the only input.  Of course, there are serious supply considerations and regular old "economic growth" considerations (including "upside risks" associated with fiscal policies).  But to be sure, inflation is a key input.  To whatever extent it makes a noticeable move up and out of this stagnant 1.7-1.8 range, bond markets will not be happy.

The afternoon brings the last of the week's big Treasury auctions.  Whereas yesterday felt a bit sleepy (thanks daylight savings time!) for markets in general, things should be more actively-traded today, and we're more likely to see a reaction to the end of the bond market supply in the event that CPI hasn't dominated the day's trading tone.