Who are the big 4 strategy consultants?

Global professional services firms EY, PwC, Deloitte and KPMG make up “the big four”. These firms offer consulting services in four main areas, including strategy. The four largest management consulting firms in the world are PwC, KPMG, Deloitte, and EY. Boston Consulting Group was initially founded in 1963 as the consulting arm of The Boston Safe Deposit and Trust Company in order to provide strategic advice to the bank's clients.