Advantage 3: Deducting Wear and Tear

As soon as one of his properties opens, Mr. Trump can deduct a set percentage of its value each year in a process called depreciation.

In the case of a billion-dollar casino, that could be more than $25 million per year in deductions, until the entire purchase value has been recovered around 40 years later, according to Bradley T. Borden, a professor at Brooklyn Law School who specializes in real estate taxation.

Mr. Trump can also use cost segregation to separate the value of the building’s components — such as the gilded bathroom fixtures and marbled interiors — from the value of the building, and depreciate them on an even more aggressive timetable.

Mr. Trump is allowed to take full advantage of these deductions to offset any of his personal income because he qualifies as a real estate professional, someone who spends at least 750 hours a year and more than 50 percent of his time working in real estate.

Most homeowners are not allowed to deduct the depreciation of their home.