I believe the reported/actual corporate rate is about half the legal rate due to exemptions, etc. We are far from the biggest corporate taxer using actual taxes due. Many companies pay nothing, like GE. Last year, GE paid nothing ... that's $zero.
...this is because you don't pay taxes on prior earnings that were losses. That's a carry-forward for losses. You already paid taxes on those dollars in prior years and are allowed to recover them tax free.
If every time you won at blackjack you had to pay taxes on it, and every time you lost at blackjack you didn't pay taxes, it would not work. If the bet were $10 per hand you would still be at zero.
But if companies had to pay money on everything they earned regardless of their losses, you'd play 100 winning and 100 losing hands for $10 each, and then have to pay taxes on $1,000 that you earned (hey you owe $350!) rather than pay taxeson what you are actually ahead.