Big Four

Big Four is the largest four accounting firms in the world: Deloitte, EY, KPMG, and PriceWaterhouseCoopers.

Definitions

According to Managerial Accounting by Braun, Tietz (5th edition),

Big Four. The largest four accounting firms in the world: Deloitte, EY, KPMG, and PriceWaterhouseCoopers.