Accounting may actually be the second-oldest profession, and Ernst & Young (E&Y) is one of the oldest practitioners. Ernst & Young is also one of the world's Big Four accounting firms (third in revenue behind PricewaterhouseCoopers and Deloitte Touche Tohmatsu, ahead of KPMG). It has some 700 offices providing auditing and accounting services in 150 countries. The firm also provides legal services and advisory services relating to emerging growth companies, human resources issues and corporate transactions (mergers and acquisitions, public offerings, and the like). E&Y has one of the world's largest tax practices, serving multinational clients that have to comply with multiple local tax laws.