These companies could lose the most from Trump’s tax plan

President Donald Trump's tax plan may cut the federal business income tax rate from 35 percent to 15 percent, but dozens of companies are already enjoying rates below the new maximum.

The plan would be a windfall for retailers like Best Buy and CVS and for financial services companies like Visa and JPMorgan Chase, which tend to pay close to the 35 percent. On the other hand, companies that have access to substantial tax deductions and are already below 15 percent could suffer if the cut comes at the expense of closing tax loopholes.

The average effective federal tax rate for profitable Fortune 500 companies was a little under 20 percent from 2008 to 2012, according to a 2014 study by the progressive tax reform organization Citizens for Tax Justice. About 35 percent of those companies were already under Trump's proposed 15 percent rate. CTJ is in the process of updating those calculations, and most companies' tax rates have been fairly consistent over the long term.

It's hard to know exactly how Trump's tax plan would affect individual companies, partly because the administration hasn't released the details of its proposal yet. Two weeks ago, Trump said he would make a "phenomenal" tax announcement in two or three weeks. On Wednesday he said tax reform was "very well finalized" but that it wouldn't come until after health-care reforms. Treasury Secretary Steven Mnuchin told CNBC on Thursday morning that he wants to see the reforms passed before Congress goes on its August recess.

According to Trump's published tax plan, "no business of any size, from a Fortune 500 to a mom and pop shop to a freelancer living job to job, will pay more than 15 percent of their business income in taxes." Mnuchin said the administration is looking at a combined plan with Republicans in Congress, who have been pushing a 20 percent business tax and a controversial border adjustment tax.

Amazon's 11 percent tax rate

The final mix of reforms could very well benefit companies that are currently paying more than 15 or 20 percent, while driving up taxes for companies that already have low rates thanks to loopholes. Trump's strategy for keeping the tax cuts revenue-neutral depends in part on eliminating some "special interest loopholes."

"You can make the basic observation that companies like Exxon Mobil that are routinely able to reduce their tax bill will likely benefit much less than companies in the retail sector, which traditionally pay a lot closer to 35 percent," said Matthew Gardner, senior fellow at CTJ. "Congress has enacted special tax breaks for a number of different industries, but retailers are generally unaffected and there aren't a lot of breaks designed for them."

Take a company like Amazon, which has paid 11 percent in taxes on its domestic income over the last eight years. According to the company's annual report, that rate was reached using a number of special deductions, including stock-based compensation deductions, accelerated depreciation deductions, research and development credits, and the domestic production activities deduction. Companies like Boeing (-1 percent from 2008 to 2012) and Honeywell (8 percent) use similar deductions and credits.

"The companies that tend to do the best tend to be companies that make a lot of capital investments, like utilities or manufacturers because the accelerated depreciation rules have been so generous over the last couple of decades," said Gardner. "They give big rewards to anyone investing in factories or machinery."

Generally, the biggest deductions are more useful for companies in utilities, telecommunications, oil and gas, manufacturing and some pharmaceutical companies, while retailers, financial services, food companies and health-care companies tend to pay closer to the statutory rate. Take a look at all the profitable Fortune 500 companies below:

The final impact of Trump's tax plan depends a lot on the revenue trade-offs that are included to pay for the cuts.

A border tax, for example, would be a hit on retailers, but dropping the business tax rate would also disproportionately help retailers. Big companies may lose some deductions, but the plan also calls for a one-time repatriation of the $2.5 trillion in corporate cash sitting offshore at a 10 percent rate, which would save companies like Apple, Microsoft and Citigroup billions of dollars.

As the plan stands now, it would increase the federal debt by $7.2 trillion over the first decade, according to the Tax Policy Center. An analysis by the Tax Foundation estimated revenues would be decreased by at least $4.4 trillion over the next decade, depending on the specific policy changes.

Lawmakers could reduce some of those revenue shortfalls by removing any number of other tax loopholes, but Gardner isn't optimistic that those changes will be implemented. It's often much easier to propose steep tax cuts than it is to work out a way to pay for them.

"It's certainly true that an even-handed revenue-neutral reform would leave some companies substantially worse off, especially those that have relied most heavily on the tax breaks being taken away," said Gardner. "But in the real world, Congress might answer the easy question of how far to cut the tax rate and avoid the hard question of how to pay for it."

Watch: Amazon's border adjustment tax loophole