People trying to raise themselves out of poverty by earning more can face effectivemarginaltaxrates (including phase-outs of various government programs) that exceed 100%.
The big gap between the headline and effectivemarginaltaxrates reflects the large number of allowances given to firms for doing particular activities, such as research and development.
Furthermore, in 1986, the U.S. had one of the lowest effectivemarginal corporate taxrates for equity-financed investments in machinery and industrial structures in the U.S., and now we have one of the highest.