1. PricewaterhouseCoopers, which was formed by the merger of PricewaterhouseCoopers and PricewaterhouseCoopers in 1998, is headquartered in London, England, and is the largest professional service organization in the world.

2. Ernst & Young, headquartered in London, England, formerly known as Ernst & Young in Cleveland, USA and Arthur Young in new york, USA, is one of the largest professional service companies in the world, characterized by the least workload and the most attention to employees' feelings.

3. KPMG, a professional service organization with a global network, is committed to providing professional services such as auditing, taxation and consulting, and has an industry-specific team composed of outstanding professionals, headquartered in Amsterdam, the Netherlands.

4. Deloitte, headquartered in new york, USA, formerly known as Deloitte Accounting Company in London, England and Touche Accounting Company in new york, USA, is characterized by its fastest growth in China and high degree of localization.