top rate
noun [ S ] uk/ˌtɒp ˈreɪt/ us/ˌtɑːp ˈreɪt/
（尤指税率）最高一级
the highest level of a payment, especially of tax
It is unlikely that they will raise the top rate of income tax before the election. 他们不太可能在大选前提高所得税的最高税率。
She pays tax at the top rate. 她按最高税率纳税。