I believe the answer is: progressive tax system
In a progressive tax system, we impose different tax rates to the people whose earning reach a certain income bracket. With the purpose of ensuring proper amount of wealth allocation.
In united states, the separation for each bracket would look like this:
Taxable Income Tax Rate
$0 - $9,525 10% of taxable income
$9,526 - $38,700 $952.50 plus 12% of the amount over $9,525
$38,701 - $82,500 $4,453.50 plus 22% of the amount over $38,700
$82,501 - $157,500 $14,089.50 plus 24% of the amount over $82,500
$157,501 - $200,000 $32,089.50 plus 32% of the amount over $157,500
$200,001 - $500,000 $45,689.50 plus 35% of the amount over $200,000
$500,001 or more $150,689.50 plus 37% of the amount over$500,000
