top brass
noun/ˌtɒp ˈbrɑːs/
/ˌtɑːp ˈbræs/
(informal) (also brass)
[uncountable + singular or plural verb] (especially North American English)- the people who are in the most important positions in a company, an organization, etc.
（公司、机构等的）最高负责人，要员，头目