A crisis of unaffordability has held the housing market hostage. That situation is not likely to change anytime soon, according to Fannie Mae’s chief economist — and there’s one culprit.

The strong economic data we've seen in the past several weeks underscore why the 10-year yield and mortgage rates rose last week.

When investors buy more Treasury bonds, their yields typically fall. Lenders often use these Treasury rates as a benchmark for setting mortgage rates. Mortgage rates tend to follow suit when Treasury rates drop due to global events — potentially making borrowing more affordable.

The Federal Reserve cut interest rates, then standard 30-year mortgage rates went up. It’s a warning that lower rates from here are not a foregone conclusion.