The Republican candidate for president is fond of saying that the U.S. is the “one of the highest-taxed countries in the world,” and he uses the statutory corporate tax of 35% as evidence in that case.

On Monday during a speech on economic policy Trump said, “The United States has the highest business tax rate” among wealthy, industrialized nations. “It’s almost 40% when you add in taxes at the state level, and in many cases, in many places it’s higher.” And he promised under a Trump presidency that no company in America would pay more than 15% a year in taxes.

Trump is likely relying on analysis from places like the right-leaning Tax Foundation, which published a study in October that claimed that the U.S.—with an average combined federal and state corporate income tax of 39.5%—had the third highest business tax rate in the world exceeded by only Chad and the United Arab Emirates.

But the story changes when you take into account the numerous corporate tax breaks, or loopholes, embedded in the system which cause the “effective” tax rate to be lower than the headline. According to a paper published by the Congressional Research Service, by this measure the United States corporate tax—at just more than 27%—was slightly below average when compared to the wealthy nations that belong to the Organization of Economic Cooperation and Development (OECD).

This difference between the headline rate of 35% and a much lower effective rate is why President Obama was able to submit a plan to Congress that lowered the headline rate to 28%, but not lose any revenue because that move would be accompanied by revenue-increasing loophole closures. So Trump’s pledge to lower corporate taxes to 15% would be a big move, though not a 20 percentage point reduction as he said in his speech.

And just because Corporate America doesn’t pay more than their foreign counterparts on average doesn’t mean there isn’t reason for corporate tax reform. The fact that so many tax breaks are needed to lower the effective rate means that different corporations are playing by different rules, and potentially succeeding or failing based on their ability to curry favor with the writers of tax law.

Unfortunately, though Republicans and Democrats agree that this state of affairs isn’t ideal, they have been unable to forge a plan for reform, because Republicans want to use reform as an opportunity to lower the overall amount of taxes paid by corporations, while President Obama wants a plan that maintains current revenue levels.