I had to look this up, from Forbes
http://www.forbes.com/sites/timwors...eral-income-tax-true-but-horribly-misleading/
Yes, it is true that nearly two-thirds of US corporations do not pay the federal corporate income tax. This is because nearly two-thirds of US corporations end up paying the personal income tax on profits, not the corporate one.
An S corporation, for United States federal income tax purposes, is a corporation that makes a valid election to be taxed under Subchapter S of Chapter 1 of the Internal Revenue Code.
In general, S corporations do not pay any federal income taxes. Instead, the corporations income or losses are divided among and passed through to its shareholders. The shareholders must then report the income or loss on their own individual income tax returns. This concept is called single taxation; if the corporation is taxed as a C corporation, it will face double taxation, meaning both the corporations profits, and the shareholders dividends, will be taxed.