The Big Four accounting firms refer to the four famous accounting firms in the world:

1. PricewaterhouseCoopers (PwC): Price water house Coopers

2. Deloitte (DTT): Deloitte-Touche

3. KPMG (KPMG): KPMG International

4. Ernst & Young (EY): Ernst & Young.

Extended information:

(1) The original PricewaterhouseCoopers International Accounting Company and Coopers International Accounting Company were merged on July 1, 1998, and are headquartered in London, England. Major international customers: IBM, Nippon Telegraph and Telephone Company, Johnson & Johnson, American Telegraph and Telephone Company, British Telecom, Dell Computer, Ford Motor Company, Chevrolet, Compaq Computer and Nokia, etc.

(2) Deloitte is headquartered in New York, USA. Its main international clients are: Microsoft, Procter & Gamble, General Motors, Vodafone, and Chrysler. (Chrysler) et al.

(3) KPMG is headquartered in Amsterdam, the Netherlands. Major international customers: General Electric, Apple, Shell, Pfizer, Nestle, Mercedes-Benz, PepsiCo, Citibank, Industrial and Commercial Bank of China, China Unicom, PetroChina, etc.

(4) Ernst & Young is headquartered in London, UK. Major international customers: Intel, Coca-Cola, Walmart, BP, Time Warner, Bank of America, McDonald's, Bank of China, China Life, etc.