compares the year-over-year change in U.S. Federal government debt and home mortage debt for each year since the heyday of the housing bubble.

"Over the past 6 years, an around $1 1/8 trillion downsizing in per annum net home mortgage financing has accompanied an around $7/8 trillion upswing in federal borrowing per annum," said Harris. In other words, the size of the mortgage bond market has shrunk by much more than the Treasury bond market has grown.

Back when the U.S. housing market was booming, the mortgage bonds it generated was an enormous source of fixed-income securities for investors.