10 Most Profitable U.S. Corporations Paid Average Tax Rate Of Just 9 Percent Last Year: Report

While some of America's biggest corporations may complain that they pay too much in taxes , a recent analysis shows that many are actually getting off pretty easy.

According to the financial site NerdWallet, the 10 most profitable U.S. companies paid an average federal tax rate of just 9 percent last year . The group includes heavyweights Exxon Mobil, Apple, Microsoft, JPMorgan Chase and General Electric. (Hat tip: Barry Ritholtz .)

Some of these companies paid more than 9 percent -- JPMorgan earned $26.7 billion in 2011, for example, and paid $3.7 billion of it, or 14 percent, to the federal government -- and some paid less, like Exxon Mobil, which only sent 2 percent of its $73.3 billion earnings to the IRS.

But the 10 companies all paid much less than the nominal corporate tax rate of 35 percent -- a number that investor and tax-the-rich advocate Warren Buffett has dismissed as "a myth ," but one that presidential front-runners Barack Obama and Mitt Romney have both proposed to lower .

The effective corporate tax rate has been on its way down for decades, recently hitting a 40-year low even as corporate profits have reached an all-time high . Many of the companies that have seen their tax rates fall in recent years -- including Exxon Mobil, Verizon, General Electric and AT&T -- are among the biggest spenders when it comes to lobbying, according to a recent analysis by the Sunlight Foundation.