Deloitte & Touche (also referred to as Deloitte Touche Tohmatsu, and branded as Deloitte.) is one of the largest professional services firms in the world and one of the Big Four auditors, along with PricewaterhouseCoopers, Ernst & Young, and KPMG.According to the firm's website as of 2007, Deloitte has approximately 150,000 professionals at work in 142 countries, delivering audit, tax, consulting, and financial advisory services.