I roto i te 1898, Robert H. Montgomery, William M. Lybrand, Arama A. Ross Jr. me tona teina T. Edward Ross hanga Lybrand, Ross Brothers ko Montgomery i roto i te United States. I roto i te 1957 Cooper Brothers; Lybrand, Bros Ross & Montgomery me te Canadian kamupene McDonald, Currie ko Co whakaae ki te tango i te ingoa Coopers & Lybrand i roto i te mahi ao. I roto i te 1973 te toru mema kamupene i roto i te UK, US ko Canada huri ratou ingoa ki Coopers & Lybrand. Na i roto i 1980 Coopers & Lybrand whakawhānui ona tohungatanga i roto i te kore utu tino mā te whiwhi Cork Gully, he kamupene ārahi i roto i taua mara i roto i te UK i 1990. I roto i te tahi mau whenua, tae atu ki te UK, Coopers & Lybrand i whakakotahi ki Deloitte Haskins & Sells ki Lyopers & Lyopers Co.
Ko Coopers & Lybrand Deloitte