Mortgage rates fell modestly today despite some weakness in underlying bond markets.  Typically, when bond yields (which move inversely with bond prices) are rising, mortgage rates tend to be higher as well.  That wasn't the case today for a few reasons.  The most obvious reason is that bond markets didn't move that much.  

Slightly more subtle is the fact that most of today's trading activity took place within yesterday's range, and yesterday ended on a low note for yields.  In other words, bonds yields were only "higher" when compared to yesterday afternoon's levels, but roughly in line with everything else.  

Finally, mortgage rates simply have not and will not keep perfect pace with the movement in broader bond markets.  As we've discussed frequently this past week, both the bonds that underlie mortgages and the lenders that depend on them will need to see the overall bond market commit to holding the new levels achieved after last week's Brexit news.  Only then will rates begin moving back within their normal distance from broader benchmarks like US Treasury yields.

Everyone with a potential loan in process wants to know if rates will drop further or if they should lock to avoid the risk of rates snapping back.  I will say that rates CAN go lower, but even before last week's Brexit news, we were already looking at diminishing returns with each new move lower.  That said, with today's rates being the lowest in more than three years, it's perfectly reasonable to wait for at least one small move higher for a signal to lock.