Please stop citing that disingenuous, misinformative fact.
The US has the highest statutory tax rates on corporate investment in the OECD. The effective tax rates on corporate income are vastly lower than that, and often actually zero — especially for those large and powerful enough to have sway over the government.
The GAO study you're citing is infamously incorrect.
1. Corporations (and humans) can carry losses forward: if they lose money in 2008 but make money in 2009, they get to even out the two years. This is only fair. Thus they can appear to pay zero tax in a year in which they made money.
2. The "effective rate" counts the aforementioned foreign retained profits as being taxed at zero. Which they're not.
3. An independent analysis found that effective corporate tax rates are "in the mid to upper 20's", and that corporations which operate solely in the US pay 35% corporate income tax:
The US has the highest statutory tax rates on corporate investment in the OECD. The effective tax rates on corporate income are vastly lower than that, and often actually zero — especially for those large and powerful enough to have sway over the government.