One source of company information that amateur stock pickers use is Value Line, which you can find in your public library. One row of data is the income tax rate as a percentage of profit.
For most companies that I have seen, the rate is 35-45%. There are exceptions, and one that I've seen are the pharmaceuticals with income tax rates of 10-15%.
On the whole, though, corporations pay a stiffer rate than I do.
I know that there is a general perception that corporations don't pay taxes thanks to loopholes, but so far, I have not seen the evidence for that.
-- I've been able to string more words into fewer ideas than anybody I know, and I'm continuing to do that.
- Alan Greenspan to the Senate Budget Committee, Sept 23, 1998