Mortgage rates haven't really been able to catch a break recently. This week is shaping up to be one of the worst since March. Since then, only 2 other weeks have been worse and they both occurred in the past month. In and of itself, today's jump in rates wouldn't be too troubling, but when added to the existing momentum, the losses are adding up. A conventional 30yr fixed scenario that had carried rates in the 2.75-2.875 neighborhood a month ago is now closer 3.125-3.25%.
Making matters more frustrating is the fact that there really isn't any great, short-term explanation for the incremental damage. Negative momentum is simply embedded, and it has been since the Fed signaled its intent to taper its bond purchases on September 22nd. Around the same time, covid case counts began turning a corner in a convincing way.
These general motivations sparked a migration in the bond market whereby traders are steadily adjusting for higher rates in the future. It would take significantly negative developments for the economy or the covid outlook for things to change. Help could also come from lower inflation (another key source of concern for bonds/rates at the moment), but that sort of help would take months to materialize and there are no great signs that such a process has even begun.