Income Property Mortgage

A mortgage. On an income property. Duh.

But why does this matter? Well, profits from rents on a commercial building are taxed at the very high ordinary income rates. So having a load of debt piled onto a commercial building is often highly tax efficient; the interest on that mortgage or debt is fully tax deductible, as if it were (and is) an operating cost of the building. Hence, most commercial properties have loads of debt, and the operating income from those building(s) then gets taxed little, if at all.

There's a reason so many billionaires got that way via commercial real estate ownership.