Question

Us federal income tax is progressive by law, but which best explains why is it sometimes regressive in practice?

Answer 1

"High-income earners use tax laws to their advantage to reduce their tax rates" is what best explains why the US federal income tax is progressive by law, but it is sometimes regressive in practice. I hope that this is the answer that you were looking for and the answer has actually come to your great help.

Answer 2

I believe the answer is: High-income earners use tax laws to their advantage to reduce their tax rates

High income earners tend to possess financial knowledge or ability to allow experts who understand the full scope of taxation laws and how to recorded the transactions in a way that make it eligible for tax deduction. This makes a lot of high income earners manage to avoid paying taxes even if they manage to obtain a lot of profit.