Deloitte Touche Tohmatsu (also branded as Deloitte) is one of the largest professional services organizations in the world and one of the Big Four auditors, along with PricewaterhouseCoopers, Ernst & Young, and KPMG.
According to the organization's website as of 2008, Deloitte has approximately 165,000 staff at work in 140 countries, delivering audit, tax, consulting and financial advisory services through its member firms.
Its global headquarters are located in Paramount Plaza, Midtown Manhattan, New York City, New York. The European headquarters is located in London.
This company is "deloitted" to make your acquaintance, particularly if you're a big business in need of accounting services. Units include Deloitte & Touche (the US accounting arm) and Deloitte Consulting. Consulting and tax each account for about a quarter of Deloitte's revenues.