marginal rate

noun [C] (also marginal tax rate, marginal rate of tax)

Definition

› ACCOUNTING, TAX the rate of tax paid on the last part of a person's or organization's income in a particular period: The law would have lowered the top marginal rate on income earned in the city. The higher marginal tax rate applies to individuals with more than $120,000 of net income. For most people, their marginal rate of tax will be higher when investing and lower when retired.

(Definition of marginal rate noun from the Cambridge Business English Dictionary © Cambridge University Press)