From Ed, my MA friend. clo
The reason mortgage rates dropped to near 4% is that the 10 year Treasury yield fell to 2.25%.
Enclosed is the chart I mentioned, of 10 year bond yields, comparing the U.S. (from 2007) to Japan (from 1990).
If Japan is a good guide, 10 year Treasury yields have a lot further down to run
DO SOMETHING!