The “Ownership” mirage

"If a homeowner has a mortgage on his house, does he really “own” the house? Well, sort of. What he “owns” is the equity in the home over and above what he owes on the mortgage. If the home is “worth” $500,000 on the market, and the homeowner still owes $400,000 on the mortgage, then he owns the incremental $100,000 of equity."