Ernst & Young (known as EY) is a multinational professional services firm headquartered in London, United Kingdom. It is one of the "Big Four" audit firms and is the third largest professional services firm in the world by aggregated revenue in 2014. The organization operates as a network of member firms which are separate legal entities in individual countries. It has 190,000 employees and more than 700 offices in over 150 countries. It provides assurance (including financial audit), tax, consulting and advisory services to companies