" Proponents of lowering the U.S. corporate income tax rate commonly point to evidence that the U.S. statutory corporate tax rate of 35 percent, as well as its average effective tax rate, which equals the amount of income tax corporations pay divided by their pretax income, are high relative to other countries. However, GAO's 2008 report on corporate tax liabilities (GAO-08-957) found that nearly 55 percent of all large U.S.-controlled corporations reported no federal tax liability in at least one year between 1998 and 2005. Given the difficult budget choices Congress faces and its need to know corporations' share of the overall tax burden, GAO was asked to assess the extent to which corporations are paying U.S. corporate income tax. In this report, among other things, GAO (1) defines average corporate ETR and describes the common methods and data used to estimate this rate and (2) estimates average ETRs based on financial statement reporting and tax reporting. To conduct this work, GAO reviewed economic and accounting literature, analyzed income and expense data that large corporations report on the Schedules M-3 that they file with Internal Revenue Service (IRS), and interviewed IRS officials. "