auditing

Deloitte & Touche is one of the Big Four accounting firms. It is made up of a series of national partnerships owned by the partners in each country. The local firms are affiliated through a global network that administers the sharing of a common brand name, standards and procedures. Deloitte Touche Tohmatsu, a Swiss verein, or membership organization, oversees Deloitte's international organization. Deloitte Touche Tomatsu doesn't perform any audits or other services for outside clients.

KPMG is one of the Big Four accounting firms. KPMG LLP, is the U.S. limited liability partnership and a member firm of the KPMG network of independent member firms affiliated with KPMG International, a Swiss cooperative.

Through its member firms, KPMG provides audit, tax and other advisory services.

PricewaterhouseCoopers (PwC) is the largest of the Big Four accounting firms, with 770 offices in 150 countries. The firm provides audit and assurance, tax advisory and consulting services to large corporations and other clients.

According to the firm's website the firm is "structured as a network of member firms, connected through membership in PricewaterhouseCoopers International Limited." PwC was formed by the merger of Price Waterhouse with Coopers & Lybrand in 1998.