What are the Big Four? 

The ‘Big Four’ refers to the biggest professional service networks in the world. The members of the Big Four include Deloitte, Ernst & Young (EY), PricewaterhouseCoopers (PwC) and Klynveld Peat Marwick Goerdeler (KPMG). 

The members of the Big Four mainly focus on auditing and accounting services, but also offer tax, strategy and management consulting. Other services include market research, assurance and legal advisory. 

As of 2021, the Big Four companies employed just over 1.1 million people worldwide. According to a survey by Statista, Deloitte had the largest workforce with close to 350,000 employees. Deloitte also generated the largest revenue in 2021, earning $50bn, with PwC and EY respectively bringing in approximately $5m and $10m less respectively.

Who are the Big Four accounting firms?

Until the late 20th century, the professional services sector was originally dominated by eight networks collectively known as the ‘Big Eight’. 

These were Arthur Andersen, Arthur Young, Coopers and Lybrand, Deloitte Haskins and Sells, Ernst & Whinney, Peat Marwick Mitchell, Price Waterhouse and Touche Ross – all US or UK companies.

Mergers between these firms, as well as the 2002 insolvency of Arthur Andersen due to its proven involvement in the Enron scandal, led to the formation of the present-day Big Four accounting firms at the turn of the 21st century. 

Why are the Big Four called the Big Four?

The nickname speaks for itself – the Big Four means that the four firms in question are the global leaders in their primary areas of business, namely auditing and accounting. Deloitte, EY, PwC and KPMG collectively audit the majority of publicly traded companies around the world, as well as many audits of private companies.

These companies also owe their Big Four definition to a number of other factors aside from revenue volume and employee numbers. They are all viewed as equally able to provide a wide range of professional services to their clients. 

The Big Four companies largely engage with firms listed in the S&P 500 (US500) and FTSE 100 (UK100) indices, which makes them attractive employes for those looking to enter the industry.