In what at first might seem a laudable effort to put the public interest ahead of his own financial gain, Mr. Trump called for abolishing the loophole. “We will eliminate the carried interest deduction and other special interest loopholes that have been so good for Wall Street investors, and people like me, but unfair to American workers,” Mr. Trump said in Detroit on Aug. 7.

But his fellow real estate investors and the Wall Street interests he lambastes needn’t worry. He’s offering them an even better tax break that renders carried interest irrelevant.

Mr. Trump has proposed a new rate — 15 percent on all corporate and business income — that is lower than the current capital gains rate of 20 percent on profits from the sale of assets, which is already well below the top tax rate on ordinary income of around 40 percent. The new lower rate would apply to “pass-through entities,” according to Mr. Trump’s plan, “Tax Reform That Will Make America Great Again.”

Pass-through entities pay no tax at the business level; as the name suggests, income is taxed at individual rates when it is distributed to the owners. Such entities include limited liability companies, or L.L.C.s, and sole proprietorships, S Corporations, and many partnerships. The conservative-leaning Tax Foundation estimates that they account for 60 percent of all business income in the United States.

While they can be found in all sectors of the economy (including private equity and hedge funds), they are especially prevalent in real estate. Mr. Trump identified 564 separate business entities in his financial disclosure forms, most of them L.L.C.s and partnerships.

That amounts to a huge tax cut even for people who had been paying taxes on carried interest at the preferential rate, “since most carried interest is generated by a business entity,” said Alan Cole, an economist at the Tax Foundation’s Center for Federal Tax Policy. The center warned last year, before Mr. Trump’s latest revisions, that his overall plan could cost over $10 trillion in reduced tax revenues over 10 years, depending on how it is calculated.