Why homeowners aren't selling

Nine out of ten mortgages in America carry an interest rate of less than 5%, which is the official level at which most new 30-year fixed-rate mortgages are now being written.

Why it matters: Houses are affordable — if you already own one. According to Fannie Mae's most recent national housing survey, 92% of homeowners say that their current home is affordable. More impressively 91% of lower-income homeowners say the same thing, up from just 79% at the end of 2017.

Were those homeowners to move, however, they would need to pay substantially more...