Deloitte is a multinational professional services network that provides audit, consulting, financial advisory, risk management, tax, and related services to clients in various industries. The company is headquartered in London, United Kingdom, and has operations in more than 150 countries. Deloitte's clients range from small and medium-sized enterprises to large multinational corporations and government agencies. The company's services include audit and assurance, consulting, financial advisory, risk advisory, tax, and legal services. Deloitte is one of the "Big Four" accounting firms, along with PwC, EY, and KPMG, and is consistently ranked as one of the largest professional services firms in the world.