Their central estimate is that the taxable income elasticity for this group is 0.46, which implies a revenue-maximizing tax rate on earned income of 56%.29 This in turn (accounting for NICs and indirect taxes) corresponds to an incometax rate of 40%.
Those returns between the bottom 50 percent and the top 25 percent pay an average effective tax rate of only 5.6 percent, accounting for only 11.8 percent of all federal incometax revenue.