Revenue of the Big Four accounting/audit firms worldwide by function 2024

In 2024, Deloitte roughly 21 billion U.S. dollars in revenue from its assurance segment, making it the leader in the assurance market among the Big Four.

The Big Four worldwide

The Big Four consist of PricewaterhouseCoopers (PwC), Deloitte, Ernst & Young (EY), and KPMG. These companies are the four largest accounting and audit firms worldwide. In 2024, they brought in more than 212 billion U.S. dollars in global combined revenue. Out of the four, Deloitte had the highest number of employees. Second in the list was Ernst & Young, followed by PwC, and KPMG. The majority of revenue generated by Deloitte came from the Americas region, as was the case with PwC and EY.

The Big Four in the U.S.

These four companies have the most influence in the accounting and audit sector in the United States, auditing over 80 percent of U.S. public companies. Out of the Big Four, Deloitte brought in the highest gross revenue in the United States. Following Deloitte was PwC, bringing in 22.75 billion U.S. dollars, then Ernst & Young, that brought in 21.46 billion U.S. dollars. KPMG brought in the least, generating 12.2 billion U.S. dollars the same year.