Download full data on Exxon Mobil’s effective tax rate from 2008 to 2010 (.xls)

Exxon Mobil Corp.’s robust balance sheets have become a poster child for what The New York Times dubs the “paradox of the United States tax code.”

The company’s large 2010 profits allowed them to lead Fortune 500’s annual ranking of the nations’ most profitable firms for the eighth time in a row. But the oil giant’s average effective tax rates are roughly half the 35 percent tax rate that currently stands as the high-water mark for American corporations. Meanwhile, Exxon Mobil and other big oil companies continue to exploit tax loopholes for nearly $4 billion in subsidies each year. These subsidies include write-offs for drilling costs and a deduction for domestic production that was intended for manufacturers, not big oil producers.

Exxon Mobil registered an average 17.6 percent federal effective corporate tax rate on its annual earnings in the three years spanning 2008 to 2010. Its average domestic profits exceeded $6.8 billion. And as a 2011 Citizens for Tax Justice report points out:

Over the past two years, ExxonMobil reported $9,910 million in pretax U.S. profits. But it enjoyed so many tax subsidies that its federal income tax bill was only $39 million—a tax rate of only 0.4 percent.

Even when Exxon Mobil had a record profit of $40 billion in 2008 due to record oil prices it had only a 31 percent effective tax rate. That’s 13 percent lower than the maximum 35 percent despite being Exxon Mobil’s fifth year as the top corporate earner in Fortune 500’s annual listing. The company paid no taxes at all to the U.S. federal government in 2009 on its domestic profits of nearly $2.6 billion. It appears that they avoided the tax man that year by legally funneling their profits through wholly owned subsidiaries in countries like the Cayman Islands, and reinvesting their earnings overseas.

More striking still is the discrepancy between Exxon Mobil’s rates and those of most American breadwinners. The company’s effective rate of 17.6 percent is nearly 16 percent below the average individual federal tax rate, which according to the Congressional Budget Office was 20.4 percent as of 2007.

Individuals in the highest quintile pay an average tax rate just over 25 percent in the United States. Exxon Mobil, meanwhile, paid approximately the same effective tax rate as Americans in the fourth income quintile—which includes Americans earning from $62,000 to $100,000 a year.

Exxon Mobil’s accounting methods mask its relatively low effective tax rate. According to CNN Money the $3.1 billion in taxes the company claims to have paid since January 2011 includes both federal and state gasoline taxes—that are really paid by drivers—as well as employee payroll taxes.

Think Progress’s Pat Garofalo rightly observes that “Exxon is counting as part of its tax burden [taxes] that it simply does not pay,” making the exorbitant subsidies the company receives even more unnecessary.

These strategic maneuverings have not been lost on congressional Democrats. Rep. Tim Bishop (D-NY) introduced a bill to repeal at least one of these tax loopholes for large oil companies including Exxon. The legislation would result in $12 billion in revenue over 10 years by removing the Section 199 domestic manufacturing tax deduction.

House Republicans successfully blocked Democratic attempts to force a vote erasing this unnecessary oil subsidy on May 5 by passing a motion, 241-171, on two drilling bills.

But this promises to be only a temporary respite for Big Oil tax breaks. And a short one at that. The Senate is expected to vote next week on the Close Big Oil Tax Loopholes Act, legislation introduced by Robert Menendez (D-NJ) and other senators to address oil prices and subsidies for the five biggest oil companies.

Seth Hanlon, Director of Fiscal Reform at the Center for American Progress, explains that the glaring contrast between:

Today’s high gas prices and inflated profits have undermined the industry’s argument that their tax breaks benefit consumers.

Meanwhile, federal budget deficits have sharpened Congress’s focus on eliminating wasteful government spending—of which oil subsidies are one of the worst examples.

Right on cue, Rep. Max Baucus (D-MT), on the morning of May 6, called on executives from Exxon Mobil and its Big Five compatriots—BP, Chevron, ConocoPhillips, and Shell—to stand before the Senate Finance Committee for a May 12 hearing on "Oil and Gas Tax Incentives and Rising Energy Prices." As of this writing, top-level representatives from each company have confirmed attendance, including ExxonMobil Chairman and CEO Rex Tillerson. He now finds himself with the difficult task of publicly rationalizing Exxon’s share of billions in subsidies, despite the company reaping enormous profits and paying relatively little in the way of taxes.

Download full data on Exxon Mobil’s effective tax rate from 2008 to 2010 (.xls)

Thanks to Seth Hanlon, Director of Fiscal Reform, Daniel J. Weiss, Senior Fellow and Director of Climate Strategy, and Tony Carrk, Policy Analyst at American Progress.