The Incredible Shrinking Corporate Tax Rate Continues to Hit New Lows for These Business Giants

It's part of a long pattern of companies paying decreasing portions of their profits in taxes.

Remember how the Tax Cuts and Jobs Act of 2017 lowered the corporate tax rate from 35% to 21% but was going to eliminate loopholes and workarounds to avoid being one giant giveaway to large companies?

Well, about that—a funny thing happened on the way to the U.S. Treasury. The biggest corporations enjoyed an average effective tax rate of 11.3%—the taxes a company ends up actually paying—according to a new study from the Institute on Taxation & Economic Policy (ITEP). The low rate is one of the reasons deficit spending soared from $666 billion in the federal government’s 2017 fiscal year to $779 billion in 2018 and $984 billion in 2019.

And the really crazy news? A good number of the Fortune 500 paid no federal income taxes at all last year. The average effective tax rate across all corporations was even lower than 11.3%.

The report identified 379 companies that were profitable and provided enough information to allow for a calculation of their effective tax rates. More than half of those 379 companies paid less than half of the 21% rate. Fifty-six paid an average effective rate of 2.2% while 91 companies paid no federal income taxes at all, or got money back.

Fortune requested a statement from the five companies listed but did not receive answers before publication.

Effective tax rates is the percent of company profits that firms send to the tax collector after they’ve accounted for deductions, tax credits from previous losses, other tax credits created by lawmakers, stock-based compensation, and legal tax avoidance schemes to cut the amount owed. The difference between effective tax rates and rates like the 21% set by statute in 2017 can cause “a debate about how to measure a firm’s profitability,” says Erica York, an economist with the Tax Foundation.

A company might show a hefty profit but have losses from previous years that wipe it out. Or in the years after purchasing a large piece of equipment, a company might take an annual paper loss on part of the equipment’s initial value—known as depreciation. It’s a standard accounting treatment that lowers the apparent profit and, thus, the amount of taxes to be paid.

Taking the long view

Data analysis over time shows that as top corporate statutory tax rates have had their ups and downs, the overall effective rate across all corporations has continued to plunge. The graph below shows both the changing statutory and effective tax rates.

Measured by the percentage of profit companies pay in taxes, corporate tax rates have drastically and steadily fallen for 65 years. That corporations pay far less in taxes than book rates is nothing new.

According to the Government Accountability Office found in a 2016 study, “at least two-thirds of all active corporations had no federal income tax liability” in each of the years from 2006 to 2012. Among the largest corporations—those with at least $10 million in assets—42.3% paid no federal income tax in 2012. Between 2008 and 2012, profitable large U.S. corporations paid about 14% of their profits in federal income tax.

IRS data for 2013 allowed a calculation of effective tax rates—verified with Ryan Dudley, a partner at accounting and advisory firm Friedman—by size of corporate assets, shown in the graph below.

The very largest corporations had the second lowest effective tax rate of any group. That multinational corporations have an advantage shouldn’t be a surprise. “As a policy matter, it is very easy to tax things that are hard to move,” Dudley says. Governments find it easier to tax labor “as opposed to businesses who can move operations, move IP, move assets overseas very easily and high net worth individuals who can move to nearby locations and pay substantially less taxes.”

Effective tax rates have spiraled down since 2013, at least among the largest corporations the study targeted. The lowest rates in 2018 were concentrated in certain industries.

Some experts have said that trying to follow the ITEP analysis was difficult. “It was hard to tie their numbers to the financial statements I looked at,” says Mary Vernon, a PhD candidate and tax researcher at University of Wisconsin-Madison’s Wisconsin School of Business who is part of a research team currently looking at effective tax rates.

But the continued downward shift of taxes after the 2017 bill does make general sense. “If you look at the worldwide effective tax rates, it does follow logic what we’re seeing,” says Eric Hananel, a principal at UHY Advisors. “Most of the very low effective tax rate companies are multinational companies. That’s where you see these very low effective tax rates, through tax planning, use of subsidiaries in low tax regions, and deferral of income offshore. I do think our corporate tax rate at 34% was too high. I’m not sure we needed to go to a 21% rate. Perhaps we could have gone to a 25%, 27% rate.”

And that might have helped moderate the explosion of the deficit and national debt.

More must-read stories from Fortune:

—2020 Crystal Ball: Predictions for the economy, politics, technology, etc.
—In scooter startups, landlords see a competitive edge and the city of the future
—Big tech companies avoided over $100 billion in taxes. What that means
—How blockchain will shake up the financial world
—What went wrong at Chime? How rapid growth became its own challenge
—Don’t miss the daily Term Sheet, Fortune’s newsletter on deals and dealmakers.