400 of America's largest corporations paid an average federal tax rate of about 11 percent on their profits last year, roughly half the official rate established under President Trump's 2017 tax law. The 2017 tax law lowered the U.S. corporate tax rate from 35 percent to 21 percent, but in practice large companies often pay far less than that because of deductions, tax breaks and other loopholes. In the first year of the law, the amount corporations paid in federal taxes on their incomes - their effective rate" - was 11.3 percent on average ... according to a report by the Institute on Taxation and Economic Policy. From 2008 to 2015, under the previous tax code, the corporations' effective rate was about 21 percent. The report also found that 91 corporations in the Fortune 500, many worth billions of dollars, paid no federal taxes last year. The findings come amid an explosion in the federal deficit, which this year rose to almost $1 trillion. Corporate tax revenue fell markedly during the first year of the tax law, from about $300 billion in 2017 to $204 billion in 2018. "When drafting the tax law, lawmakers could have eliminated special breaks and loopholes in the corporate tax to offset the cost of reducing the statutory rate," the report says. "Instead, the new law introduced many new breaks and loopholes, though it eliminated some old ones." The 91 profitable Fortune 500 corporations that paid no federal tax in 2018 earned a combined $101 billion last year. As a group, their effective federal tax rate was -5.9 percent.