When a series of big U.S. companies last year moved to reincorporate abroad in inversion deals, some Republican lawmakers and tax policy critics blamed the high U.S. corporate tax rate. The average effective tax rate for the six companies was 20.3 percent for 2011-2013, Reuters found, using an estimation method reviewed by tax experts that was based on public data for U.S. profits and U.S. taxes. The Reuters analysis suggests that the surge in inversion transactions may not have had much to do with the statutory corporate income tax.