Tax policy expert: The 35% corporate rate is a myth, so cutting it won't bring overseas money back

Corporate tax rate looks high on paper: Pro
Corporate tax rate looks high on paper: Pro

Don't expect big companies to bring profits back from overseas in response to a U.S. corporate tax cut, said Matthew Gardner of the Institute on Taxation and Economic Policy.

The lead author of a new report titled "The 35 Percent Corporate Tax Myth" told CNBC on Friday that scores of profitable Fortune 500 companies had, at least at one point during the past eight years, not paid any taxes. The U.S. will always have companies offshoring their earnings, and a tax cut promised by President Donald Trump and Republican leaders on Capitol Hill won't change that, he added.

"Zero percent, which is what [companies] are paying in the Caymans, is always going to look good compared to 35, 15, 20 percent," Gardner told "Squawk on the Street." "Whatever tax rate you name, as long as zero percent is available, these companies are always going to find a way to shift their profits into tax havens."

In addition to offshoring profits, companies use a variety of loopholes to scoot around paying taxes, and all of them are completely legal, he said. These tax breaks, he argued, have been expanded by Congress in recent years, making a true 35 percent federal corporate tax a myth.

"You add up all of these tax breaks and what you see is that there are entire industries that are finding ways to almost zero out their taxes with astonishing regularity," Gardner says.

Current plans for tax reform, Gardner said, have not focused on closing these loopholes and eliminating breaks.