Who Are the Big Four of Financial Auditing and What Is Their Role?

The four largest audit firms, known as the “Big Four”, provide audit, assurance, tax, advisory and consulting services to the world's largest companies. Their dominant position in the audit sector, together with their considerable influence over financial reporting, has consolidated their status as the most powerful players in the world of audit and consulting. But who exactly are they, and what precisely is their role?

The Big Four in Audit: Definition and Composition

In the worlds of finance and accounting, the term “Big Four” refers to the four largest audit and consulting firms in the world. These international giants play an essential role in certifying company accounts, managing risk and providing strategic advice. Their influence goes well beyond the narrow scope of financial audit: today they support the largest organisations in their economic, legal and technological decisions.

The Big Four are Deloitte, PwC (PricewaterhouseCoopers), EY (Ernst & Young) and KPMG. These four groups have dominated the global audit market since the 1990s, following a series of mergers and failures that reduced the former “Big Eight” to this quartet of leaders. Together, they account for more than 70% of the global audit market for large listed companies, and employ several hundred thousand people across hundreds of countries.

Their strength rests on a shared model: a strong international presence, standardised working methods, and the ability to mobilise experts in every area of corporate performance, from finance to cybersecurity and sustainability.

The Big 4 in Audit: Which Firms Make Up the Group?

The Big Four are not simply audit firms: they are genuine consulting multinationals, each with its own culture, specialisms and history. While they share a common core business, namely the certification of accounts and advice to companies, their expertise and approaches differ slightly.

Deloitte, founded in London in 1845, is today the largest of the four in terms of revenue and headcount. Present in more than 150 countries, it offers audit services as well as consulting in strategy, finance, risk and technology. Deloitte is known for its innovative approach, particularly in digital transformation and the application of data analytics to audit.

PwC (PricewaterhouseCoopers), created in 1998 by the merger of Price Waterhouse and Coopers & Lybrand, is one of the oldest players in the sector. With a strong footprint in Europe and the United States, PwC supports multinationals and SMEs alike on audit, tax, sustainability and human resources issues. Its credo: building trust between companies and their stakeholders.

EY (Ernst & Young) has established itself as a major player in consulting and performance. Present in more than 150 countries, it focuses on innovation, sustainable finance and regulatory compliance. EY is also strongly committed to ethics and governance, which are essential dimensions of modern auditing.

Finally, KPMG was created from the merger of several European and American firms. The company stands out for its expertise in management consulting and risk management. Its mission: to help companies grow responsibly and to strengthen the transparency of their financial practices.

The Big Four in Consulting: What Are Their Activities?

Although the Big Four are first and foremost known for their audit engagements, their scope of action goes well beyond verifying accounts. Over the years, these groups have become global consulting players, able to work in almost every area of corporate performance.

Their primary mission remains the certification of financial statements, a key role in guaranteeing the reliability and transparency of accounting information. But alongside this regulated activity, the Big Four have developed a comprehensive range of strategic, financial, legal, tax and technology consulting services.

They support companies through transformation: digitalisation, process optimisation, risk management, regulatory compliance, the ecological transition and cybersecurity. Their strength lies in their ability to combine sector expertise, analytical power and international experience.

The Big Four in Accounting: Their Role in Accountancy

Beyond their audit and consulting engagements, the Big Four play a central role in accounting. They help companies to keep, consolidate and analyse their accounts, ensuring compliance with national and international standards.

Their mission is to guarantee the reliability and consistency of the financial information provided to investors, shareholders and supervisory authorities. Thanks to their specialist teams, they are involved in everything from preparing balance sheets to putting robust accounting procedures in place or managing complex reporting projects.

The Big Four also contribute to the evolution of accounting practice. Through their research, their participation in professional bodies and their technological innovations, they directly influence the way accounting is practised worldwide.

Finally, these firms train thousands of chartered accountants and young auditors every year. They are thus a genuine school of rigour, ethics and technical skill, which makes the Big Four essential players in the quality and transparency of financial reporting in the global economy.

The History of the Big 4: From the Big 8 to the Big 4

Before becoming the Big Four, the world of audit was once made up of eight major firms, nicknamed the Big Eight. These firms already dominated the international audit market in the 1980s. But over time, a series of mergers and consolidations reduced their number.

Between 1989 and 1998, several major tie-ups took place: Ernst & Whinney merged with Arthur Young to form EY, while Price Waterhouse joined forces with Coopers & Lybrand to create PwC. At the same time, the collapse of Arthur Andersen in 2002, following the Enron scandal, marked the definitive end of the Big Five and gave way to today's quartet: Deloitte, PwC, EY and KPMG.

Why Join a Big Four?

Working for a Big Four firm is a unique opportunity for young graduates in finance, accounting, audit or management. These firms offer a demanding and formative environment, recognised for the quality of its learning and the richness of its experience.

Joining a Big Four means, first and foremost, benefiting from continuous training alongside the best experts in the field. Young recruits take part in a wide variety of engagements, working with clients from very different sectors, from banking to energy, tech and luxury. This diversity helps them to develop a global view of business and a solid economic grounding.

It is also a fantastic springboard for an international career. Thanks to their worldwide networks, the Big Four offer numerous opportunities to work abroad, as well as professional recognition that employers around the world value.

Training to Join a Big Four in Audit or Consulting

Joining a Big Four cannot be improvised: these firms look for candidates who are both technically strong and equipped with excellent analytical skills. Specialist training in audit, finance or management control is therefore essential to acquire the skills and rigour that these demanding careers require.

Future recruits must master international accounting principles, understand the issues behind financial performance and know how to analyse an organisation's risks. But beyond theoretical knowledge, the Big Four also value human qualities: curiosity, agility, a sense of service and a taste for teamwork.

To prepare for these high-responsibility careers, it is essential to follow a recognised programme that combines academic teaching, professional experience and an international outlook.

The Master in Audit & Control at EDC Paris Business School trains experts capable of assessing company performance and guaranteeing the reliability of their financial information. The programme combines accounting rigour, mastery of control tools and a strategic understanding of the organisation. Students develop a dual technical and managerial skill set that is highly sought after by the major audit and consulting firms.

EDC Paris Business School also offers other complementary pathways: the MSc Corporate Finance, to specialise in financial management, company valuation and investment strategies. The Master in Management, a comprehensive, career-oriented course that provides a global view of management and finance professions. The Bachelor in Finance, ideal for starting a career in accounting, management control or audit, with solid foundations and a practical approach to finance.

The Big Four are renowned for their excellence, and working for one of them will always be good for your career in finance. But the selection process is rigorous, and the work is very demanding: you will spend long hours in the office and you will feel the pressure of meeting deadlines and producing reports, especially during audit and tax filing periods. It is for you to weigh up the pros and cons but, if you are still interested, do not hesitate to go for it!